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Space debris (also known as space junk, space pollution, space waste, space trash, or space garbage) are defunct human-made objects in space—principally in
Earth orbit Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi) in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes  days (1 sidereal year), during which time Eart ...
—which no longer serve a useful function. These include derelict spacecraft—nonfunctional spacecraft and abandoned launch vehicle stages—mission-related debris, and particularly numerous in Earth orbit, fragmentation debris from the breakup of derelict rocket bodies and spacecraft. In addition to derelict human-made objects left in orbit, other examples of space debris include fragments from their disintegration,
erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...
and
collision In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great fo ...
s or even paint flecks, solidified liquids expelled from spacecraft, and unburned particles from solid rocket motors. Space debris represents a risk to spacecraft. Space debris is typically a negative externality—it creates an external cost on others from the initial action to launch or use a spacecraft in near-Earth orbit—a cost that is typically not taken into account nor fully accounted for in the cost by the launcher or payload owner. Several spacecraft, both crewed and uncrewed, have been damaged or destroyed by space debris. The measurement, mitigation, and potential removal of debris are conducted by some participants in the
space industry Space industry refers to economic activities related to manufacturing components that go into Earth's orbit or beyond, delivering them to those regions, and related services. Owing to the prominence of the satellite-related activities, some sour ...
."Space debris by the numbers"
''ESA'', January 2019. Retrieved 5 March 2019
, the US Space Surveillance Network reported 21,901 artificial objects in orbit above the Earth, including 4,450 operational satellites. However, these are just the objects large enough to be tracked. , more than 128 million pieces of debris smaller than , about 900,000 pieces of debris 1–10 cm, and around 34,000 of pieces larger than were estimated to be in orbit around the Earth. When the smallest objects of artificial space debris (paint flecks, solid rocket exhaust particles, etc.) are grouped with micrometeoroids, they are together sometimes referred to by space agencies as MMOD (Micrometeoroid and Orbital Debris). Collisions with debris have become a hazard to spacecraft; the smallest objects cause damage akin to
sandblasting Sandblasting, sometimes known as abrasive blasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove s ...
, especially to solar panels and optics like telescopes or
star tracker A star tracker is an optical device that measures the positions of stars using photocells or a camera. As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may ...
s that cannot easily be protected by a
ballistic Ballistics may refer to: Science * Ballistics, the science that deals with the motion, behavior, and effects of projectiles ** Forensic ballistics, the science of analyzing firearm usage in crimes ** Internal ballistics, the study of the proc ...
shield. Below Earth- altitude, pieces of debris are denser than
meteoroid A meteoroid () is a small rocky or metallic body in outer space. Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than this are classified as mi ...
s; most are dust from solid rocket motors, surface erosion debris like paint flakes, and frozen coolant from Soviet nuclear-powered satellites.A. Rossi et al
"Effects of the RORSAT NaK Drops on the Long Term Evolution of the Space Debris Population"
University of Pisa, 1997.
For comparison, the
International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ( ...
orbits in the range, while the two most recent large debris events—the 2007 Chinese antisat weapon test and the
2009 satellite collision On February 10, 2009, two communications satellites—the active commercial Iridium 33 and the derelict Russian military Kosmos 2251—accidentally collided at a speed of and an altitude of above the Taymyr Peninsula in Siberia. It was the fi ...
—occurred at altitude. The ISS has Whipple shielding to resist damage from small MMOD; however, known debris with a collision chance over 1/10,000 are avoided by maneuvering the station.


History

Space debris began to accumulate in Earth orbit immediately with the first launch of an
artificial satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisoto ...
Sputnik 1 into orbit in October 1957. But even before that, beside natural ejecta from Earth, humans might have produced ejecta that became space debris, as in the August 1957 Pascal B test. After the launch of Sputnik, the
North American Aerospace Defense Command North American Aerospace Defense Command (NORAD ), known until March 1981 as the North American Air Defense Command, is a combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and protection ...
(NORAD) began compiling a database (the
Space Object Catalog The United States Space Surveillance Network (SSN) detects, tracks, catalogs and identifies artificial objects orbiting Earth, e.g. active/inactive satellites, spent rocket bodies, or fragmentation debris. The system is the responsibility of Uni ...
) of all known rocket launches and objects reaching orbit: satellites, protective shields and upper-stages of
launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and ...
s.
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
later published modified versions of the database in
two-line element set A two-line element set (TLE) is a data format encoding a list of orbital elements of an Earth-orbiting object for a given point in time, the ''epoch''. Using a suitable prediction formula, the state (position and velocity) at any point in the past ...
, and beginning in the early 1980s the CelesTrak bulletin board system re-published them. The trackers (NORAD) who fed the database were aware of other objects in orbit, many of which were the result of in-orbit explosions.Schefter, p. 48. Some were deliberately caused during the 1960s
anti-satellite weapon Anti-satellite weapons (ASAT) are space weapons designed to incapacitate or destroy satellites for strategic or tactical purposes. Several nations possess operational ASAT systems. Although no ASAT system has been utilised in warfare, a few ...
(ASAT) testing, and others were the result of rocket stages blowing up in orbit as leftover propellant expanded and ruptured their tanks. To improve tracking, NORAD employee John Gabbard kept a more detailed database of as many objects as he could identify. Studying the explosions, In March 1971, Gabbard developed a technique for predicting the orbital paths of their products, and Gabbard diagrams (or plots) are now widely used. These studies were used to improve the modeling of orbital evolution and decay. When the NORAD database became publicly available during the 1970s, techniques developed for the asteroid-belt were applied to the study to the database of known artificial satellite Earth objects. In addition to approaches to debris reduction where time and natural gravitational/atmospheric effects help to clear space debris, or a variety of technological approaches that have been proposed (with most not implemented) to reduce space debris, a number of scholars have observed that institutional factors—political, legal, economic and cultural "rules of the game"—are the greatest impediment to the cleanup of near-Earth space. By 2014, there was little commercial incentive to reduce space debris, since the cost of dealing with it is not assigned to the entity producing it, but rather falls on all users of the space environment, and rely on human society as a whole that benefits from space technologies and knowledge. A number of suggestions for improving institutions so as to increase the incentives to reduce space debris have been made. These include government mandates to create incentives, as well as companies coming to see economic benefit to reducing debris more aggressively than existing government standard practices. In 1979 NASA founded the Orbital Debris Program to research mitigation measures for space debris in Earth orbit.


Debris growth

During the 1980s, NASA and other U.S. groups attempted to limit the growth of debris. One trial solution was implemented by
McDonnell Douglas McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it pro ...
for the Delta launch vehicle, by having the booster move away from its payload and vent any propellant remaining in its tanks. This eliminated one source for pressure buildup in the tanks which had previously caused them to explode and create additional orbital debris.Schefter, p. 50. Other countries were slower to adopt this measure and, due especially to a number of launches by the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
, the problem grew throughout the decade.See charts, Hoffman p. 7. A new battery of studies followed as NASA, NORAD and others attempted to better understand the orbital environment, with each adjusting the number of pieces of debris in the critical-mass zone upward. Although in 1981 (when Schefter's article was published) the number of objects was estimated at 5,000, new detectors in the Ground-based Electro-Optical Deep Space Surveillance system found new objects. By the late 1990s, it was thought that most of the 28,000 launched objects had already decayed and about 8,500 remained in orbit. By 2005 this was adjusted upward to 13,000 objects, and a 2006 study increased the number to 19,000 as a result of an ASAT test and a satellite collision. In 2011, NASA said that 22,000 objects were being tracked. A 2006 NASA model suggested that if no new launches took place the environment would retain the then-known population until about 2055, when it would increase on its own.Stefan Lovgren
"Space Junk Cleanup Needed, NASA Experts Warn."
''National Geographic News'', 19 January 2006.
Richard Crowther of Britain's
Defence Evaluation and Research Agency The Defence Evaluation and Research Agency (DERA) was a part of the UK Ministry of Defence (MoD) between 1995 and 2 July 2001. At the time it was the United Kingdom's largest science and technology organisation. It was regarded by its official h ...
said in 2002 that he believed the cascade would begin about 2015. The National Academy of Sciences, summarizing the professional view, noted widespread agreement that two bands of LEO space—900 to and —were already past critical density. In the 2009 European Air and Space Conference, University of Southampton researcher Hugh Lewis predicted that the threat from space debris would rise 50 percent in the next decade and quadruple in the next 50 years. , more than 13,000 close calls were tracked weekly. A 2011 report by the U.S. National Research Council warned NASA that the amount of orbiting space debris was at a critical level. According to some computer models, the amount of space debris "has reached a tipping point, with enough currently in orbit to continually collide and create even more debris, raising the risk of spacecraft failures". The report called for international regulations limiting debris and research of disposal methods.


Debris history in particular years

*, 19,000 debris over were tracked by
United States Space Surveillance Network The United States Space Surveillance Network (SSN) detects, tracks, catalogs and identifies artificial objects orbiting Earth, e.g. active/inactive satellites, spent rocket bodies, or fragmentation debris. The system is the responsibility of Uni ...
. *, estimates of more than 170 million debris smaller than , about 670,000 debris 1–10 cm, and approximately 29,000 larger pieces of debris are in orbit."How many space debris objects are currently in orbit?"
''ESA'', July 2013. Retrieved 6 February 2016
*, nearly 18,000 artificial objects are orbiting above Earth, including 1,419 operational satellites. *, nearly 20,000 artificial objects in orbit above the Earth, including 2,218 operational satellites.


Characterization


Size

There are estimated to be over 128 million pieces of debris smaller than as of January 2019. There are approximately 900,000 pieces from 1 to 10 cm. The current count of large debris (defined as 10 cm across or larger) is 34,000. The technical measurement cutoff is c. .
''NASA'', March 2012. Retrieved 31 January 2016
As of 2020 there is 8,000 metric tons of debris in orbit with no signs of slowing down.


Low Earth orbit

In the orbits nearest to Earth—less than
orbital altitude A geocentric orbit or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,216 pieces of space debris ...
, referred to as low-Earth orbit (LEO)—there have traditionally been few "universal orbits" that keep a number of spacecraft in particular rings (in contrast to GEO, a single orbit that is widely used by over 500 satellites). This is beginning to change in 2019, and several companies have begun to deploy the early phases of
satellite internet constellation A satellite internet constellation is a constellation of artificial satellites providing satellite internet service. In particular, the term has come to refer to a new generation of very large constellations (sometimes referred to as a megaco ...
s, which will have many universal orbits in LEO with 30 to 50 satellites per orbital plane and altitude. Traditionally, the most populated LEO orbits have been a number of sun-synchronous satellites that keep a constant angle between the Sun and the
orbital plane The orbital plane of a revolving body is the geometric plane in which its orbit lies. Three non-collinear points in space suffice to determine an orbital plane. A common example would be the positions of the centers of a massive body (host) an ...
, making Earth observation easier with consistent sun angle and lighting. Sun-synchronous orbits are polar, meaning they cross over the polar regions. LEO satellites orbit in many planes, typically up to 15 times a day, causing frequent approaches between objects. The density of satellites—both active and derelict—is much higher in LEO.Matt Ford
"Orbiting space junk heightens risk of satellite catastrophes."
''Ars Technica'', 27 February 2009.
Orbits are affected by gravitational perturbations (which in LEO include unevenness of the Earth's gravitational field due to variations in the density of the planet), and collisions can occur from any direction. The average impact speed of collisions in Low Earth Orbit is 10 km/s with maximums reaching above 14 km/s due to orbital eccentricity. The
2009 satellite collision On February 10, 2009, two communications satellites—the active commercial Iridium 33 and the derelict Russian military Kosmos 2251—accidentally collided at a speed of and an altitude of above the Taymyr Peninsula in Siberia. It was the fi ...
occurred at a closing speed of ,"What are hypervelocity impacts?"
''ESA'', 19 February 2009.
creating over 2,000 large debris fragments. These debris cross many other orbits and increase debris collision risk. It is theorized that a sufficiently large collision of spacecraft could potentially lead to a cascade effect, or even make some particular
low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...
s effectively unusable for long term use by orbiting satellites, a phenomenon known as the
Kessler syndrome The Kessler syndrome (also called the Kessler effect, collisional cascading, or ablation cascade), proposed by NASA scientist Donald J. Kessler in 1978, is a scenario in which the density of objects in low Earth orbit (LEO) due to space pollutio ...
. The theoretical effect is projected to be a theoretical runaway
chain reaction A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events. Chain reactions are one way that sys ...
of collisions that could occur, exponentially increasing the number and density of space debris in low-Earth orbit, and has been hypothesized to ensue beyond some critical density.Lisa Grossman
"NASA Considers Shooting Space Junk with Lasers"
, ''wired'', 15 March 2011.
Crewed space missions are mostly at altitude and below, where air drag helps clear zones of fragments. The upper atmosphere is not a fixed density at any particular orbital altitude; it varies as a result of
atmospheric tide Atmospheric tides are global-scale periodic oscillations of the atmosphere. In many ways they are analogous to ocean tides. Atmospheric tides can be excited by: *The regular day–night cycle in the Sun's heating of the atmosphere (insolation) *T ...
s and expands or contracts over longer time periods as a result of
space weather Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the time varying conditions within the Solar System, including the solar wind, emphasizing the space surrounding the Earth, including conditions in the ...
. These longer-term effects can increase drag at lower altitudes; the 1990s expansion was a factor in reduced debris density.Kessler 1991, p. 65. Another factor was fewer launches by Russia; the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
made most of their launches in the 1970s and 1980s.


Higher altitudes

At higher altitudes, where air drag is less significant, orbital decay takes longer. Slight
atmospheric drag In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding flu ...
, lunar perturbations, Earth's gravity perturbations,
solar wind The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...
and solar
radiation pressure Radiation pressure is the mechanical pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field. This includes the momentum of light or electromagnetic radiation of any wavelength that is a ...
can gradually bring debris down to lower altitudes (where it decays), but at very high altitudes this may take millennia.Kessler 1991, p. 268. Although high-altitude orbits are less commonly used than LEO and the onset of the problem is slower, the numbers progress toward the critical threshold more quickly. Many communications satellites are in geostationary orbits (GEO), clustering over specific targets and sharing the same orbital path. Although velocities are low between GEO objects, when a satellite becomes derelict (such as Telstar 401) it assumes a geosynchronous orbit; its orbital inclination increases about .8° and its speed increases about per year. Impact velocity peaks at about . Orbital perturbations cause longitude drift of the inoperable spacecraft and
precession Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In oth ...
of the orbital plane. Close approaches (within 50 meters) are estimated at one per year. The collision debris pose less short-term risk than from an LEO collision, but the satellite would likely become inoperable. Large objects, such as solar-power satellites, are especially vulnerable to collisions. Although the ITU now requires proof a satellite can be moved out of its orbital slot at the end of its lifespan, studies suggest this is insufficient. Since GEO orbit is too distant to accurately measure objects under , the nature of the problem is not well known. Satellites could be moved to empty spots in GEO, requiring less maneuvering and making it easier to predict future motion. Satellites or boosters in other orbits, especially stranded in geostationary transfer orbit, are an additional concern due to their typically high crossing velocity. Despite efforts to reduce risk, spacecraft collisions have occurred. The European Space Agency telecom satellite Olympus-1 was struck by a
meteoroid A meteoroid () is a small rocky or metallic body in outer space. Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than this are classified as mi ...
on 11 August 1993 and eventually moved to a
graveyard orbit A graveyard orbit, also called a junk orbit or disposal orbit, is an orbit that lies away from common operational orbits. One significant graveyard orbit is a supersynchronous orbit well beyond geosynchronous orbit. Some satellites are moved into ...
."The Olympus failure"
''ESA press release'', 26 August 1993.
On 29 March 2006, the Russian Express-AM11 communications satellite was struck by an unknown object and rendered inoperable;"Notification for Express-AM11 satellite users in connection with the spacecraft failure"
''Russian Satellite Communications Company'', 19 April 2006.
its engineers had enough contact time with the satellite to send it into a graveyard orbit.


Sources


Dead spacecraft

In 1958, the United States launched
Vanguard I Vanguard 1 (Harvard designation: 1958-Beta 2, COSPAR ID: 1958-005B ) is an American satellite that was the fourth artificial Earth-orbiting satellite to be successfully launched, following Sputnik 1, Sputnik 2, and Explorer 1. It was launche ...
into a medium Earth orbit (MEO). , it, and the upper stage of its launch rocket, were the oldest surviving artificial space objects still in orbit.Julian Smith
"Space Junk"
''USA Weekend'', 26 August 2007.
In a catalog of known launches until July 2009, the Union of Concerned Scientists listed 902 operational satellites from a known population of 19,000 large objects and about 30,000 objects launched. An example of additional derelict satellite debris is the remains of the 1970s/80s Soviet
RORSAT Upravlyaemy Sputnik Aktivnyy (russian: Управляемый Спутник Активный for Controlled Active Satellite), or US-A, also known in the west as Radar Ocean Reconnaissance Satellite or RORSAT (GRAU index 17F16K), was a series of ...
naval surveillance satellite program. The satellites' BES-5 nuclear reactors were cooled with a coolant loop of sodium-potassium alloy, creating a potential problem when the satellite reached end of life. While many satellites were nominally boosted into medium-altitude graveyard orbits, not all were. Even satellites that had been properly moved to a higher orbit had an eight-percent probability of puncture and coolant release over a 50-year period. The coolant freezes into droplets of solid sodium-potassium alloy, forming additional debris.A. Rossi et al
"Effects of the RORSAT NaK Drops on the Long Term Evolution of the Space Debris Population"
University of Pisa, 1997.
In February 2015, the
USAF The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...
Defense Meteorological Satellite Program Flight 13 (DMSP-F13) exploded on orbit, creating at least 149 debris objects, which were expected to remain in orbit for decades. Orbiting satellites have been deliberately destroyed.
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
and USSR/
Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
have conducted over 30 and 27 ASAT tests, respectively, followed by 10 from China and one from
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. The most recent ASATs were Chinese interception of FY-1C, trials of Russian PL-19 Nudol, American interception of USA-193 and Indian interception of unstated live satellite.


Lost equipment

Space debris includes a glove lost by astronaut Ed White on the first American space-walk (EVA), a camera lost by Michael Collins near
Gemini 10 Gemini 10 (officially Gemini X) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1966 crewed spaceflight in NASA's Gemini program. It was the 8th crewed Gemini flight, the 16th crewed American flight, and t ...
, a thermal blanket lost during STS-88, garbage bags jettisoned by Soviet cosmonauts during
Mir ''Mir'' (russian: Мир, ; ) was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet Union and later by Russia. ''Mir'' was the first modular space station and was assembled in orbit from 1986 to&n ...
's 15-year life, a wrench, and a toothbrush.
Sunita Williams Sunita Lyn Williams (born September 19, 1965) is an American astronaut and United States Navy officer who formerly held the records for most spacewalks by a woman (seven) and most spacewalk time for a woman (50 hours, 40 minutes). Williams was ...
of
STS-116 STS-116 was a Space Shuttle mission to the International Space Station (ISS) flown by Space Shuttle '' Discovery''. ''Discovery'' lifted off on 9 December 2006 at 20:47:35 EST. A previous launch attempt on 7 December had been canceled due to cl ...
lost a camera during an EVA. During an
STS-120 STS-120 was a Space Shuttle mission to the International Space Station (ISS) that launched on 23 October 2007 from the Kennedy Space Center, Florida. The mission is also referred to as ISS-10A by the ISS program. STS-120 delivered the ''Harmony' ...
EVA to reinforce a torn solar panel, a pair of pliers was lost, and in an STS-126 EVA, Heidemarie Stefanyshyn-Piper lost a briefcase-sized tool bag.


Boosters

In characterizing the problem of space debris, it was learned that much debris was due to rocket upper stages (e.g. the Inertial Upper Stage) which end up in orbit, and break up due to decomposition of unvented unburned fuel. However, a major known impact event involved an (intact) Ariane booster. Although NASA and the
United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...
now require upper-stage passivation, other launchers do not. Lower stages, like the Space Shuttle's solid rocket boosters or Apollo program's Saturn IB launch vehicles, do not reach orbit. On 11 March 2000 a Chinese Long March 4 CBERS-1 upper stage exploded in orbit, creating a debris cloud."Debris from explosion of Chinese rocket detected by University of Chicago satellite instrument"
University of Chicago press release, 10 August 2000.
A Russian
Briz-M The Briz-K, Briz-KM and Briz-M (russian: Бриз-К, КM and M meaning ''Breeze-K, KM and M'') are Russian liquid-propellant rocket orbit insertion upper stages manufactured by Khrunichev State Research and Production Space Center and used ...
booster stage exploded in orbit over South Australia on 19 February 2007. Launched on 28 February 2006 carrying an Arabsat-4A
communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth ...
, it malfunctioned before it could use up its propellant. Although the explosion was captured on film by astronomers, due to the orbit path the debris cloud has been difficult to measure with radar. By 21 February 2007, over 1,000 fragments were identified. A 14 February 2007 breakup was recorded by Celestrak. Eight breakups occurred in 2006, the most since 1993. Another Briz-M broke up on 16 October 2012 after a failed 6 August
Proton-M The Proton-M, (Протон-М) GRAU index 8K82M or , is an expendable Russian heavy-lift launch vehicle derived from the Soviet-developed Proton. It is built by Khrunichev, and launched from sites 81 and 200 at the Baikonur Cosmodrome in Ka ...
launch. The amount and size of the debris was unknown. A
Long March 7 , stages = {{plainlist, * CZ-7: Two * CZ-7A: Three {{cite web, url=https://www.space.com/china-space-program-new-long-march-rockets.html, last=Jones, first=Andrew, title=China prepares to launch new rockets as part of push to boost spac ...
rocket booster created a fireball visible from portions of Utah, Nevada, Colorado, Idaho and California on the evening of 27 July 2016; its disintegration was widely reported on social media. In 2018–2019, three different
Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Mart ...
Centaur second stages have broken up. In December 2020, scientists confirmed that a previously detected near-Earth object, 2020 SO, was rocket booster space junk launched in 1966 orbiting Earth and the Sun.


Weapons

A past debris source was the testing of anti-satellite weapons (ASATs) by the U.S. and Soviet Union during the 1960s and 1970s.
North American Aerospace Defense Command North American Aerospace Defense Command (NORAD ), known until March 1981 as the North American Air Defense Command, is a combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and protection ...
(NORAD) files only contained data for Soviet tests, and debris from U.S. tests were only identified later.Note that the list Schefter was presented only identified USSR ASAT tests. By the time the debris problem was understood, widespread ASAT testing had ended; the U.S.
Program 437 Program 437 was the second anti-satellite weapons program of the U.S. military.Peebles, Curtis. "High Frontier: The United States Air Force and the Military Space Program", 1997 The US anti-satellite weapons program began development in the e ...
was shut down in 1975. The U.S. restarted their ASAT programs in the 1980s with the Vought
ASM-135 ASAT The ASM-135 ASAT is an air-launched anti-satellite multistage missile that was developed by Ling-Temco-Vought's LTV Aerospace division. The ASM-135 was carried exclusively by United States Air Force (USAF) F-15 Eagle fighter aircraft. Developm ...
. A 1985 test destroyed a satellite orbiting at , creating thousands of debris larger than . Due to the altitude, atmospheric drag decayed the orbit of most debris within a decade. A ''de facto'' moratorium followed the test.David Wright
"Debris in Brief: Space Debris from Anti-Satellite Weapons"
''Union of Concerned Scientists'', December 2007.
China's government was condemned for the military implications and the amount of debris from the 2007 anti-satellite missile test, the largest single space debris incident in history (creating over 2,300 pieces golf-ball size or larger, over 35,000 or larger, and one million pieces or larger). The target satellite orbited between and , the portion of near-Earth space most densely populated with satellites. Since atmospheric drag is low at that altitude, the debris is slow to return to Earth, and in June 2007 NASA's Terra environmental spacecraft maneuvered to avoid impact from the debris. Dr. Brian Weeden, U.S. Air Force officer and Secure World Foundation staff member, noted that the 2007 Chinese satellite explosion created an orbital debris of more than 3,000 separate objects that then required tracking. On 20 February 2008, the U.S. launched an SM-3 missile from the USS ''Lake Erie'' to destroy a defective U.S. spy satellite thought to be carrying of toxic hydrazine propellant. The event occurred at about , and the resulting debris has a perigee of or lower. The missile was aimed to minimize the amount of debris, which (according to Pentagon Strategic Command chief Kevin Chilton) had decayed by early 2009. On 27 March 2019, Indian Prime Minister
Narendra Modi Narendra Damodardas Modi (; born 17 September 1950) is an Indian politician serving as the 14th and current Prime Minister of India since 2014. Modi was the Chief Minister of Gujarat from 2001 to 2014 and is the Member of Parliament fro ...
announced that India shot down one of its own LEO satellites with a ground-based missile. He stated that the operation, part of ''Mission Shakti'', would defend the country's interests in space. Afterwards, US
Air Force Space Command The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...
announced they were tracking 270 new pieces of debris but expected the number to grow as data collection continues. On 15 November 2021 the Russian Defense Ministry destroyed Kosmos 1408 orbiting at around 450 km, creating "more than 1,500 pieces of trackable debris and hundreds of thousands of pieces of un-trackable debris" according to the US State Department. The vulnerability of satellites to debris and the possibility of attacking LEO satellites to create debris clouds has triggered speculation that it is possible for countries unable to make a precision attack. An attack on a satellite of or more would heavily damage the LEO environment.


Hazards


To spacecraft

Space junk can be a hazard to active satellites and spacecraft. It has been theorized that
Earth orbit Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi) in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes  days (1 sidereal year), during which time Eart ...
could even become impassable if the risk of collision grows too high. However, since the risk to spacecraft increases with the time of exposure to high debris densities, it is more accurate to say that LEO would be rendered ''unusable'' by orbiting craft. The threat to craft ''passing through'' LEO to reach higher orbit would be much lower owing to the very short time span of the crossing.


Uncrewed spacecraft

Although spacecraft are typically protected by Whipple shields, solar panels, which are exposed to the Sun, wear from low-mass impacts. Even small impacts can produce a cloud of plasma which is an electrical risk to the panels. Satellites are believed to have been destroyed by micrometeorites and (small) orbital debris (MMOD). The earliest suspected loss was of Kosmos 1275, which disappeared on 24 July 1981 (a month after launch). Kosmos contained no volatile propellant, therefore, there appeared to be nothing internal to the satellite which could have caused the destructive explosion which took place. However, the case has not been proven and another hypothesis forwarded is that the battery exploded. Tracking showed it broke up, into 300 new objects. Many impacts have been confirmed since. For example, on 24 July 1996, the French microsatellite Cerise was hit by fragments of an Ariane-1 H-10 upper-stage booster which exploded in November 1986. On 29 March 2006, the Russian Ekspress AM11 communications satellite was struck by an unknown object and rendered inoperable. On 13 October 2009,
Terra Terra may often refer to: * Terra (mythology), primeval Roman goddess * An alternate name for planet Earth, as well as the Latin name for the planet Terra may also refer to: Geography Astronomy * Terra (satellite), a multi-national NASA scienti ...
suffered a single battery cell failure anomaly and a battery heater control anomaly which were subsequently considered likely the result of an MMOD strike. On 12 March 2010, Aura lost power from one-half of one of its 11 solar panels and this was also attributed to an MMOD strike. On 22 May 2013,
GOES 13 Goes () is a city and municipality in the southwestern Netherlands on Zuid-Beveland, in the province of Zeeland. The city of Goes has approximately 27,000 residents. History Goes was founded in the 10th century on the edge of a creek: de Kort ...
was hit by an MMOD which caused it to lose track of the stars that it used to maintain an operational attitude. It took nearly a month for the spacecraft to return to operation. The first major satellite collision occurred on 10 February 2009. The derelict satellite Kosmos 2251 and the operational
Iridium 33 Iridium 33 was a communications satellite launched by Russia for Iridium Communications. It was launched into low Earth orbit from Site 81/23 at the Baikonur Cosmodrome at 01:36 UTC on 14 September 1997, by a Proton-K rocket with a Block DM2 up ...
collided, Becky Iannotta and Tariq Malik
"U.S. Satellite Destroyed in Space Collision"
, space.com, 11 February 2009
over northern Siberia. The relative speed of impact was about , or about . Both satellites were destroyed, creating thousands of pieces of new smaller debris, with legal and political liability issues unresolved even years later.Iridium 33 and Cosmos 2251, Three Years Later
, Michael Listner, Space Safety Magazine, 10 February 2012, accessed 14 December 2019.
Becky Iannotta

, space.com, 11 February 2009. Retrieved 11 February 2009.
On 22 January 2013,
BLITS BLITS (Ball Lens In The Space) is a Russian satellite launched on September 17, 2009, as a secondary payload on a Soyuz-2.1b/Fregat, from the Baikonur Cosmodrome in Kazakhstan. The satellite is totally passive and spherical, and is tracked usi ...
(a Russian laser-ranging satellite) was struck by debris suspected to be from the
2007 Chinese anti-satellite missile test On 11 January 2007, China conducted an anti-satellite missile test. A Chinese weather satellite—the FY-1C (COSPAR 1999-025A) polar orbit satellite of the Fengyun series, at an altitude of , with a mass of —was destroyed by a kinetic kill v ...
, changing both its orbit and rotation rate. Satellites sometimes perform Collision Avoidance Maneuvers and satellite operators may monitor space debris as part of maneuver planning. For example, in January 2017, the European Space Agency made the decision to alter orbit of one of its three
Swarm Swarm behaviour, or swarming, is a collective behaviour exhibited by entities, particularly animals, of similar size which aggregate together, perhaps milling about the same spot or perhaps moving ''en masse'' or migrating in some direction. ...
mission spacecraft, based on data from the US
Joint Space Operations Center The Combined Space Operations Center (CSpOC) is a U.S.–led multinational space operations center that provides command and control of space forces for United States Space Command's Combined Force Space Component Command. The CSpOC is located at ...
, to lower the risk of collision from Cosmos-375, a derelict Russian satellite.


Crewed spacecraft

Crewed flights are naturally particularly sensitive to the hazards that could be presented by space debris conjunctions in the orbital path of the spacecraft. Examples of occasional avoidance maneuvers, or longer-term space debris wear, have occurred in Space Shuttle missions, the MIR space station, and the International Space Station.


= Space Shuttle missions

= From the early Space Shuttle missions, NASA used NORAD space monitoring capabilities to assess the Shuttle's orbital path for debris. In the 1980s, this used a large proportion of NORAD capacity. The first collision-avoidance maneuver occurred during STS-48 in September 1991,Rob Matson
"Satellite Encounters"
''Visual Satellite Observer's Home Page''.
a seven-second thruster burn to avoid debris from the derelict satellite Kosmos 955. Similar maneuvers were initiated on missions 53, 72 and 82. One of the earliest events to publicize the debris problem occurred on 's second flight, STS-7. A fleck of paint struck its front window, creating a pit over wide. On
STS-59 STS-59 was a Space Shuttle program mission that took place in 1994. The launch was chronicled by the 1994 Discovery Channel special about the Space Shuttle program. Crew Mission highlights 9 April ''Endeavour'' began its sixth mission on t ...
in 1994, ''Endeavour'''s front window was pitted about half its depth. Minor debris impacts increased from 1998. Window chipping and minor damage to thermal protection system tiles (TPS) were already common by the 1990s. The Shuttle was later flown tail-first to take a greater proportion of the debris load on the engines and rear cargo bay, which are not used in orbit or during descent, and thus are less critical for post-launch operation. When flying attached to the
ISS The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA (J ...
, the two connected spacecraft were flipped around so the better-armored station shielded the orbiter. A NASA 2005 study concluded that debris accounted for approximately half of the overall risk to the Shuttle.Kelly, John
"Debris is Shuttle's Biggest Threat"
, space.com, 5 March 2005.
Executive-level decision to proceed was required if catastrophic impact was likelier than 1 in 200. On a normal (low-orbit) mission to the ISS the risk was approximately 1 in 300, but the Hubble telescope repair mission was flown at the higher orbital altitude of where the risk was initially calculated at a 1-in-185 (due in part to the 2009 satellite collision). A re-analysis with better debris numbers reduced the estimated risk to 1 in 221, and the mission went ahead. Debris incidents continued on later Shuttle missions. During
STS-115 STS-115 was a Space Shuttle mission to the International Space Station (ISS) flown by . It was the first assembly mission to the ISS after the ''Columbia'' disaster, following the two successful ''Return to Flight'' missions, STS-114 and STS-12 ...
in 2006 a fragment of
circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich struc ...
bored a small hole through the radiator panels in ''Atlantis''s cargo bay. On STS-118 in 2007 debris blew a bullet-like hole through ''Endeavour''s radiator panel.


= ''Mir''

= Impact wear was notable on ''Mir'', the Soviet space station, since it remained in space for long periods with its original solar module panels.


= International Space Station

= The ISS also uses Whipple shielding to protect its interior from minor debris. However, exterior portions (notably its solar panels) cannot be protected easily. In 1989, the ISS panels were predicted to degrade approximately 0.23% in four years due to the "sandblasting" effect of impacts with small orbital debris. An avoidance maneuver is typically performed for the ISS if "there is a greater than one-in-10,000 chance of a debris strike". , there have been sixteen maneuvers in the fifteen years the ISS had been in orbit. By 2019, over 1,400 meteoroid and orbital debris (MMOD) impacts had been recorded on the ISS. As another method to reduce the risk to humans on board, ISS operational management asked the crew to shelter in the
Soyuz Soyuz is a transliteration of the Cyrillic text Союз ( Russian and Ukrainian, 'Union'). It can refer to any union, such as a trade union (''profsoyuz'') or the Union of Soviet Socialist Republics (Сою́з Сове́тских Социалис ...
on three occasions due to late debris-proximity warnings. In addition to the sixteen thruster firings and three Soyuz-capsule shelter orders, one attempted maneuver was not completed due to not having the several days' warning necessary to upload the maneuver timeline to the station's computer. A March 2009 event involved debris believed to be a piece of the Kosmos 1275 satellite. In 2013, the ISS operations management did not make a maneuver to avoid any debris, after making a record four debris maneuvers the previous year.


Kessler syndrome

The Kessler syndrome, proposed by NASA scientist Donald J. Kessler in 1978, is a theoretical scenario in which the density of objects in
low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...
(LEO) is high enough that collisions between objects could cause a cascade effect where each collision generates space debris that increases the likelihood of further collisions. He further theorized that one implication if this were to occur is that the distribution of debris in orbit could render space activities and the use of
satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioi ...
s in specific orbital ranges economically impractical for many generations. The growth in the number of objects as a result of the late-1990s studies sparked debate in the space community on the nature of the problem and the earlier dire warnings. According to Kessler's 1991 derivation and 2001 updates, the LEO environment in the altitude range should be cascading. However, only one major satellite collision incident has occurred: the 2009 satellite collision between Iridium 33 and Cosmos 2251. The lack of obvious short-term cascading has led to speculation that the original estimates overstated the problem. According to Kessler in 2010 however, a cascade may not be obvious until it is well advanced, which might take years.Jan Stupl et al
"Debris-debris collision avoidance using medium power ground-based lasers"
2010 Beijing Orbital Debris Mitigation Workshop, 18–19 October 2010, see graph p. 4


On Earth

Although most debris burns up in the atmosphere, larger debris objects can reach the ground intact. According to NASA, an average of one cataloged piece of debris has fallen back to Earth each day for the past 50 years. Despite their size, there has been no significant property damage from the debris. Burning up in the atmosphere may also contribute to atmospheric pollution. Numerous small cylindrical tanks from space objects have been found, designed to hold fuel or gasses.


Tracking and measurement


Tracking from the ground

Radar and optical detectors such as lidar are the main tools for tracking space debris. Although objects under have reduced orbital stability, debris as small as 1 cm can be tracked, however determining orbits to allow re-acquisition is difficult. Most debris remain unobserved. The
NASA Orbital Debris Observatory NASA Orbital Debris Observatory (NODO) was an astronomical observatory located in the Lincoln National Forest near Cloudcroft, New Mexico approximately northeast of Alamogordo. From 1995 to 2002 it hosted two telescopes funded and operated by ...
tracked space debris with a liquid mirror transit telescope. FM Radio waves can detect debris, after reflecting off them onto a receiver. Optical tracking may be a useful early-warning system on spacecraft. The U.S. Strategic Command keeps a catalog of known orbital objects, using ground-based
radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...
and telescopes, and a space-based telescope (originally to distinguish from hostile missiles). The 2009 edition listed about 19,000 objects. Other data come from the ESA Space Debris Telescope, TIRA,, ''fas.org''. , date-accessed=8 March 2006. the Goldstone,
Haystack Hay is grass, legumes, or other herbaceous plants that have been cut and dried to be stored for use as animal fodder, either for large grazing animals raised as livestock, such as cattle, horses, goats, and sheep, or for smaller domesticated ...
, and EISCAT radars and the Cobra Dane phased array radar, to be used in debris-environment models like the ESA Meteoroid and Space Debris Terrestrial Environment Reference (MASTER).


Measurement in space

Returned space hardware is a valuable source of information on the directional distribution and composition of the (sub-millimetre) debris flux. The LDEF satellite deployed by mission STS-41-C ''Challenger'' and retrieved by STS-32 '' Columbia'' spent 68 months in orbit to gather debris data. The EURECA satellite, deployed by STS-46 ''
Atlantis Atlantis ( grc, Ἀτλαντὶς νῆσος, , island of Atlas) is a fictional island mentioned in an allegory on the hubris of nations in Plato's works '' Timaeus'' and '' Critias'', wherein it represents the antagonist naval power that b ...
'' in 1992 and retrieved by STS-57 ''Endeavour'' in 1993, was also used for debris study. The solar arrays of Hubble were returned by missions
STS-61 STS-61 was the first NASA Hubble Space Telescope servicing mission, and the fifth flight of the Space Shuttle ''Endeavour''. The mission launched on 2 December 1993 from Kennedy Space Center (KSC) in Florida. The mission restored the spacebor ...
''Endeavour'' and
STS-109 STS-109 (SM3B) was a Space Shuttle mission that launched from the Kennedy Space Center on 1 March 2002. It was the 108th mission of the Space Shuttle program, the 27th flight of the orbiter '' Columbia'' and the fourth servicing of the Hubble ...
''Columbia'', and the
impact craters An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...
studied by the ESA to validate its models. Materials returned from Mir were also studied, notably the
Mir Environmental Effects Payload The ''Mir'' Environmental Effects Payload (MEEP) was a set of four experiments installed on the Russian space station ''Mir'' from March 1996 to October 1997 to study the effects of space debris impacts and exposure to the space environment on a ...
(which also tested materials intended for the ISS).


Gabbard diagrams

A debris cloud resulting from a single event is studied with scatter plots known as Gabbard diagrams, where the perigee and apogee of fragments are plotted with respect to their orbital period. Gabbard diagrams of the early debris cloud prior to the effects of perturbations, if the data were available, are reconstructed. They often include data on newly observed, as yet uncatalogued fragments. Gabbard diagrams can provide important insights into the features of the fragmentation, the direction and point of impact.David Portree and Joseph Loftus
"Orbital Debris: A Chronology"
, NASA, 1999, p. 13.


Dealing with debris

An average of about one tracked object per day has been dropping out of orbit for the past 50 years, averaging almost three objects per day at
solar maximum Solar maximum is the regular period of greatest solar activity during the Sun's 11-year solar cycle. During solar maximum, large numbers of sunspots appear, and the solar irradiance output grows by about 0.07%. On average, the solar cycle tak ...
(due to the heating and expansion of the Earth's atmosphere), but one about every three days at
solar minimum Solar minimum is the regular period of least solar activity in the Sun's 11-year solar cycle. During solar minimum, sunspot and solar flare activity diminishes, and often does not occur for days at a time. On average, the solar cycle takes abou ...
, usually five and a half years later. In addition to natural atmospheric effects, corporations, academics and government agencies have proposed plans and technology to deal with space debris, but , most of these are theoretical, and there is no extant business plan for debris reduction. A number of scholars have also observed that institutional factors—political, legal, economic, and cultural "rules of the game"—are the greatest impediment to the cleanup of near-Earth space. There is little commercial incentive to act, since costs are not assigned to polluters, though a number of technological solutions have been suggested. However, effects to date are limited. In the US, governmental bodies have been accused of backsliding on previous commitments to limit debris growth, "let alone tackling the more complex issues of removing orbital debris." The different methods for removal of space debris have been evaluated by the
Space Generation Advisory Council The Space Generation Advisory Council (SGAC), in support of the United Nations Programme on Space Applications, is a non-governmental organization and professional network. that "''aims to bring the views of students and young space professiona ...
, including French astrophysicist Fatoumata Kébé.


Growth mitigation

As of the 2010s, several technical approaches to the mitigation of the growth of space debris are typically undertaken, yet no comprehensive legal regime or cost assignment structure is in place to reduce space debris in the way that terrestrial pollution has reduced since the mid-20th century. To avoid excessive creation of artificial space debris, many—but not all—satellites launched to above-low-Earth-orbit are launched initially into
elliptical orbit In astrodynamics or celestial mechanics, an elliptic orbit or elliptical orbit is a Kepler orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. In a stricter sense, i ...
s with perigees inside Earth's atmosphere so the orbit will quickly decay and the satellites then will destroy themselves upon
reentry Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the ...
into the atmosphere. Other methods are used for spacecraft in higher orbits. These include passivation of the spacecraft at the end of its useful life; as well as the use of upper stages that can reignite to decelerate the stage to intentionally deorbit it, often on the first or second orbit following payload release; satellites that can, if they remain healthy for years, deorbit themselves from the lower orbits around Earth. Other satellites (such as many CubeSats) in low orbits below approximately orbital altitude depend on the energy-absorbing effects of the upper atmosphere to reliably deorbit a spacecraft within weeks or months. Increasingly, spent upper stages in higher orbits—orbits for which low-delta-v deorbit is not possible, or not planned for—and architectures that support satellite passivation, at end of life are passivated at end of life. This removes any internal energy contained in the vehicle at the end of its mission or useful life. While this does not remove the debris of the now derelict rocket stage or satellite itself, it does substantially reduce the likelihood of the spacecraft destructing and creating many smaller pieces of space debris, a phenomenon that was common in many of the early generations of US and Soviet spacecraft. Upper stage passivation (e.g. of Delta boosters) by releasing residual propellants reduces debris from orbital explosions; however even as late as 2011, not all upper stages implement this practice. SpaceX used the term "propulsive passivation" for the final maneuver of their six-hour demonstration mission (
STP-2 The Space Test Program (STP) is the primary provider of spaceflight for the United States Department of Defense (DoD) space science and technology community. STP is managed by a group within the Advanced Systems and Development Directorate, a d ...
) of the Falcon 9 second stage for the US Air Force in 2019, but did not define what all that term encompassed. With a "one-up, one-down" launch-license policy for Earth orbits, launchers would rendezvous with, capture and de-orbit a derelict satellite from approximately the same orbital plane. Another possibility is the
robotic Robotics is an interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist humans. Robotics integrate ...
refueling of satellites. Experiments have been flown by NASA, and SpaceX is developing large-scale on-orbit propellant transfer technology. Another approach to debris mitigation is to explicitly design the mission architecture to always leave the rocket second-stage in an elliptical
geocentric orbit A geocentric orbit or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,216 pieces of space debri ...
with a low-perigee, thus ensuring rapid orbital decay and avoiding long-term orbital debris from spent rocket bodies. Such missions will often complete the payload placement in a final orbit by the use of low-thrust
electric propulsion Spacecraft electric propulsion (or just electric propulsion) is a type of spacecraft propulsion technique that uses electrostatic or electromagnetic fields to accelerate mass to high speed and thus generate thrust to modify the velocity of a sp ...
or with the use of a small kick stage to circularize the orbit. The kick stage itself may be designed with the excess-propellant capability to be able to self-deorbit.


Self-removal

Although the ITU requires geostationary satellites to move to a graveyard orbit at the end of their lives, the selected orbital areas do not sufficiently protect GEO lanes from debris. Rocket stages (or satellites) with enough propellant may make a direct, controlled de-orbit, or if this would require too much propellant, a satellite may be brought to an orbit where atmospheric drag would cause it to eventually de-orbit. This was done with the French Spot-1 satellite, reducing its atmospheric re-entry time from a projected 200 years to about 15 by lowering its altitude from to about . The Iridium constellation – 95 communication satellites launched during the five-year period between 1997 and 2002 – provides a set of data points on the limits of self-removal. The satellite operator –
Iridium Communications Iridium Communications Inc. (formerly Iridium Satellite LLC) is a publicly traded American company headquartered in McLean, Virginia. Iridium operates the Iridium satellite constellation, a system of 66 active satellites and 9 in-orbit spares us ...
– remained operational over the two-decade life of the satellites (albeit with a company name change through a corporate bankruptcy during the period) and, by December 2019, had "completed disposal of the last of its 65 working legacy satellites." However, this process left 30 satellites with a combined mass of (, or nearly a third of the mass of this constellation) in LEO orbits at approximately altitude, where self-decay is quite slow. Of these satellites, 29 simply failed during their time in orbit and were thus unable to self-deorbit, while one – Iridium 33 – was involved in the 2009 satellite collision with the derelict Russian military satellite Kosmos-2251. No contingency plan was laid for the removal of satellites that were unable to remove themselves. In 2019, the Iridium CEO, Matt Desch, said that Iridium would be willing to pay an active-debris-removal company to deorbit its remaining first-generation satellites if it were possible for an unrealistically low cost, say " per deorbit, but eacknowledged that price would likely be far below what a debris-removal company could realistically offer. 'You know at what point t’sa no-brainer, but expect the cost is really in the millions or tens of millions, at which price I know it doesn’t make sense." Passive methods of increasing the orbital decay rate of spacecraft debris have been proposed. Instead of rockets, an
electrodynamic tether Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetism, electromagnetic principles as electrical generator, generators, by converting their kinetic energy to ele ...
could be attached to a spacecraft at launch; at the end of its lifetime, the tether would be rolled out to slow the spacecraft. Other proposals include a booster stage with a sail-like attachment and a large, thin, inflatable balloon envelope.


External removal

A variety of approaches have been proposed, studied, or had ground subsystems built to use other spacecraft to remove existing space debris. A consensus of speakers at a meeting in Brussels in October 2012, organized by the Secure World Foundation (a U.S. think tank) and the French International Relations Institute, reported that removal of the largest debris would be required to prevent the risk to spacecraft becoming unacceptable in the foreseeable future (without any addition to the inventory of dead spacecraft in LEO). To date in 2019, removal costs and legal questions about ownership and the authority to remove defunct satellites have stymied national or international action. Current space law retains ownership of all satellites with their original operators, even debris or spacecraft which are defunct or threaten active missions. Multiple companies made plans in the late 2010s to conduct external removal on their satellites in mid-LEO orbits. For example,
OneWeb OneWeb (legally Network Access Associates Ltd) is a communications company that aims to build broadband satellite Internet services. The company is headquartered in London, and has offices in Virginia, US and a satellite manufacturing facility ...
planned to utilize onboard self-removal as "plan A" for satellite deorbiting at the end of life, but if a satellite were unable to remove itself within one year of end of life, OneWeb would implement "plan B" and dispatch a reusable (multi-transport mission) space tug to attach to the satellite at an already built-in capture target via a grappling fixture, to be towed to a lower orbit and released for re-entry.


Remotely controlled vehicles

A well-studied solution uses a remotely controlled
vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), ...
to rendezvous with, capture, and return debris to a central station.Erika Carlson et al, "Final design of a space debris removal system", NASA/CR-189976, 1990. One such system is Space Infrastructure Servicing, a commercially developed refueling depot and service spacecraft for communications satellites in geosynchronous orbit originally scheduled for a 2015 launch."Intelsat Picks MacDonald, Dettwiler and Associates Ltd. for Satellite Servicing"
, CNW Newswire, 15 March 2011. Retrieved 15 July 2011.
The SIS would be able to "push dead satellites into graveyard orbits."Peter de Selding

''Space News'', 3 March 2010. Retrieved 15 July 2011.
The Advanced Common Evolved Stage family of upper stages is being designed with a high leftover-propellant margin (for derelict capture and de-orbit) and in-space refueling capability for the high
delta-v Delta-''v'' (more known as "change in velocity"), symbolized as ∆''v'' and pronounced ''delta-vee'', as used in spacecraft flight dynamics, is a measure of the impulse per unit of spacecraft mass that is needed to perform a maneuver such as ...
required to de-orbit heavy objects from geosynchronous orbit.Frank Zegler and Bernard Kutter
"Evolving to a Depot-Based Space Transportation Architecture"
AIAA SPACE 2010 Conference & Exposition, 30 August-2 September 2010, AIAA 2010–8638.
A tug-like satellite to drag debris to a safe altitude for it to burn up in the atmosphere has been researched. When debris is identified the satellite creates a difference in potential between the debris and itself, then using its thrusters to move itself and the debris to a safer orbit. A variation of this approach is for the remotely controlled vehicle to rendezvous with debris, capture it temporarily to attach a smaller de-orbit satellite and drag the debris with a tether to the desired location. The "mothership" would then tow the debris-smallsat combination for
atmospheric entry Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the ent ...
or move it to a graveyard orbit. One such system is the proposed Busek ORbital DEbris Remover (ORDER), which would carry over 40 SUL (satellite on umbilical line) de-orbit satellites and propellant sufficient for their removal. On 7 January 2010 Star, Inc. reported that it received a contract from the
Space and Naval Warfare Systems Command The Naval Information Warfare Systems Command (NAVWARSYSCOM), based in San Diego, is one of six SYSCOM Echelon II organizations within the United States Navy and is the Navy's technical authority and acquisition command for C4ISR (Command, Contro ...
for a feasibility study of the ElectroDynamic Debris Eliminator (EDDE) propellantless spacecraft for space-debris removal. In February 2012 the Swiss Space Center at
École Polytechnique Fédérale de Lausanne École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...
announced the Clean Space One project, a
nanosatellite A small satellite, miniaturized satellite, or smallsat is a satellite of low mass and size, usually under . While all such satellites can be referred to as "small", different classifications are used to categorize them based on mass. Satellites ca ...
demonstration project for matching orbit with a defunct Swiss nanosatellite, capturing it and de-orbiting together. The mission has seen several evolutions to reach a pac-man inspired capture model. In 2013, Space Sweeper with Sling-Sat (4S), a grappling satellite which captures and ejects debris was studied. In 2022, a Chinese satellite, SJ-21, grabbed an unused satellite and "threw" it into an orbit with a lower risk for it to collide. In December 2019, the European Space Agency awarded the first contract to clean up space debris. The €120 million mission dubbed
ClearSpace-1 The ClearSpace-1 (ClearSpace One) mission is an ESA Space Debris Removal mission led by ClearSpace SA (a spin-off of the EPFL in Lausanne) and its industrial team. The mission's objective is to demonstrate the complete value chain of Active Debri ...
(a spinoff from the EPFL project) is slated to launch in 2025. It aims to remove a 100 kg VEga Secondary Payload Adapter (Vespa) left by
Vega flight VV02 Vega flight VV02 was the second flight of the Vega launcher. It occurred from the Guiana Space Centre on 7 May 2013 at 02:06:31UTC. Payload The flight was a multi-payload mission that deployed 3 satellites (2 Earth observation satellites and ...
in an orbit in 2013. A "chaser" will grab the junk with four robotic arms and drag it down to Earth's atmosphere where both will burn up.


Laser methods

The
laser broom A laser broom is a proposed ground-based laser beam-powered propulsion system whose purpose is to sweep space debris out of the path of other artificial satellites such as the International Space Station. It would heat one side of an object ...
uses a ground-based
laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
to
ablate Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for a ...
the front of the debris, producing a rocket-like thrust that slows the object. With continued application, the debris would fall enough to be influenced by atmospheric drag. During the late 1990s, the U.S. Air Force's Project Orion was a laser-broom design. Although a test-bed device was scheduled to launch on a Space Shuttle in 2003, international agreements banning powerful laser testing in orbit limited its use to measurements.Justin Mullin
"A clean sweep: NASA plans to carry out a spot of housework."
''New Scientist'', 16 August 2000.
The 2003 Space Shuttle ''Columbia'' disaster postponed the project and according to Nicholas Johnson, chief scientist and program manager for NASA's Orbital Debris Program Office, "There are lots of little gotchas in the Orion final report. There's a reason why it's been sitting on the shelf for more than a decade." The momentum of the laser-beam
photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always ...
s could directly impart a thrust on the debris sufficient to move small debris into new orbits out of the way of working satellites. NASA research in 2011 indicates that firing a laser beam at a piece of space junk could impart an impulse of per second, and keeping the laser on the debris for a few hours per day could alter its course by per day.James Mason et al
"Orbital Debris-Debris Collision Avoidance"
, arXiv:1103.1690v2, 9 March 2011.
One drawback is the potential for material degradation; the energy may break up the debris, adding to the problem. A similar proposal places the laser on a satellite in Sun-synchronous orbit, using a pulsed beam to push satellites into lower orbits to accelerate their reentry. A proposal to replace the laser with an
Ion Beam Shepherd An ion-beam shepherd (IBS) is a concept in which the orbit and/or attitude of a spacecraft or a generic orbiting body is modified by having a beam of quasi-neutral plasma impinging against its surface to create a force and/or a torque on the tar ...
has been made, and other proposals use a foamy ball of
aerogel Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely low ...
or a spray of water, inflatable balloons,
electrodynamic tether Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetism, electromagnetic principles as electrical generator, generators, by converting their kinetic energy to ele ...
s,
electroadhesion Electroadhesion is the electrostatic effect of astriction between two surfaces subjected to an electrical field. Applications include the retention of paper on plotter surfaces, astrictive robotic prehension (electrostatic grippers) etc. Clamping p ...
, and dedicated anti-satellite weapons.


Nets

On 28 February 2014, Japan's
Japan Aerospace Exploration Agency The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orb ...
(JAXA) launched a test "space net" satellite. The launch was an operational test only. In December 2016 the country sent a space junk collector via Kounotori 6 to the ISS by which JAXA scientists experiment to pull junk out of orbit using a tether. The system failed to extend a 700-meter tether from a space station resupply vehicle that was returning to Earth. On 6 February the mission was declared a failure and leading researcher Koichi Inoue told reporters that they "believe the tether did not get released". Since 2012, the European Space Agency has been working on the design of a mission to remove large space debris from orbit. The mission,
e.Deorbit e.Deorbit was a planned European Space Agency active space debris removal mission developed as a part of their Clean Space initiative. The launch was planned for 2025 on board a Vega launch vehicle. Funding of the mission was stopped in 2018 ...
, is scheduled for launch during 2023 with an objective to remove debris heavier than from LEO. Several capture techniques are being studied, including a net, a harpoon and a combination robot arm and clamping mechanism.


Harpoon

The
RemoveDEBRIS RemoveDEBRIS was a satellite research project intending to demonstrate various space debris removal technologies. The mission was led by the Surrey Space Centre from the University of Surrey with the satellite's platform manufactured by Surrey ...
mission plan is to test the efficacy of several ADR technologies on mock targets in low Earth orbit. In order to complete its planned experiments the platform is equipped with a net, a harpoon, a laser ranging instrument, a dragsail, and two
CubeSat A CubeSat is a class of miniaturized satellite based around a form factor consisting of cubes. CubeSats have a mass of no more than per unit, and often use commercial off-the-shelf (COTS) components for their electronics and structure. CubeSats ...
s (miniature research satellites). The mission was launched on 2 April 2018.


National and international regulation

There is no international treaty minimizing space debris. However, the
United Nations Committee on the Peaceful Uses of Outer Space The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) is a United Nations committee whose main task is to review and foster international cooperation in the peaceful uses of outer space, as well as to consider legal issues ar ...
(COPUOS) published voluntary guidelines in 2007, using a variety of earlier national regulatory attempts at developing standards for debris mitigation. As of 2008, the committee was discussing international "rules of the road" to prevent collisions between satellites. By 2013, a number of national legal regimes existed, "Orbital Debris – Important Reference Documents."
, NASA Orbital Debris Program Office.
typically instantiated in the launch licenses that are required for a launch in all spacefaring
nations A nation is a community of people formed on the basis of a combination of shared features such as language, history, ethnicity, culture and/or society. A nation is thus the collective identity of a group of people understood as defined by those ...
. The U.S. issued a set of standard practices for civilian (NASA) and military ( DoD and USAF) orbital-debris mitigation in 2001. The standard envisioned disposal for final mission orbits in one of three ways: 1) atmospheric reentry where even with "conservative projections for solar activity, atmospheric drag will limit the lifetime to no longer than 25 years after completion of mission;" 2) maneuver to a "storage orbit:" move the spacecraft to one of four very broad
parking orbit A parking orbit is a temporary orbit used during the launch of a spacecraft. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory. The alternative to a parking orbit is ''di ...
ranges (, , above , or out of Earth orbit completely and into any
heliocentric orbit A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun i ...
; 3) "Direct retrieval: Retrieve the structure and remove it from orbit as soon as practicable after completion of mission." The standard articulated in option 1, which is the standard applicable to most satellites and derelict upper stages launched, has come to be known as the "25-year rule." The US updated the Orbital Debris Mitigation Standard Practices (ODMSP) in December 2019, but made no change to the 25-year rule even though " ny in the space community believe that the timeframe should be less than 25 years." There is no consensus however on what any new timeframe might be. In 2002, the European Space Agency (ESA) worked with an international group to promulgate a similar set of standards, also with a "25-year rule" applying to most Earth-orbit satellites and upper stages. Space agencies in Europe began to develop technical guidelines in the mid-1990s, and ASI, UKSA,
CNES The (CNES; French: ''Centre national d'études spatiales'') is the French government space agency (administratively, a "public administration with industrial and commercial purpose"). Its headquarters are located in central Paris and it is und ...
, DLR and ESA signed a "European Code of Conduct" in 2006, which was a predecessor standard to the ISO international standard work that would begin the following year. In 2008, ESA further developed "its own "Requirements on Space Debris Mitigation for Agency Projects" which "came into force on 1 April 2008." Germany and France have posted bonds to safeguard the property from debris damage. The "direct retrieval" option (option no. 3 in the US "standard practices" above) has rarely been done by any spacefaring nation (exception, USAF
X-37 The Boeing X-37, also known as the Orbital Test Vehicle (OTV), is a reusable robotic spacecraft. It is boosted into space by a launch vehicle, then re-enters Earth's atmosphere and lands as a spaceplane. The X-37 is operated by the United State ...
) or commercial actor since the earliest days of spaceflight due to the cost and complexity of achieving direct retrieval, but the ESA has scheduled a 2025 demonstration mission (Clearspace-1) to do this with a single small derelict upper stage at a projected cost of €120 million not including the launch costs. By 2006, the Indian Space Research Organization (ISRO) had developed a number of technical means of debris mitigation (upper stage passivation, propellant reserves for movement to graveyard orbits, etc.) for ISRO launch vehicles and satellites, and was actively contributing to inter-agency debris coordination and the efforts of the UN COPUOS committee. In 2007, the
ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...
began preparing an
international standard international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International Or ...
for space-debris mitigation. By 2010, ISO had published "a comprehensive set of space system engineering standards aimed at mitigating space debris. ith primary requirementsdefined in the top-level standard, ISO 24113." By 2017, the standards were nearly complete. However, these standards are not binding on any party by ISO or any international jurisdiction. They are simply available for use in any of a variety of voluntary ways. They "can be adopted voluntarily by a spacecraft manufacturer or operator, or brought into effect through a commercial contract between a customer and supplier, or used as the basis for establishing a set of national regulations on space debris mitigation." The voluntary ISO standard also adopted the "25-year rule" for the "LEO protected region" below altitude that has been previously (and still is, ) used by the US, ESA, and UN mitigation standards, and identifies it as "an upper limit for the amount of time that a space system shall remain in orbit after its mission is completed. Ideally, the time to deorbit should be as short as possible (i.e., much shorter than 25 years)". Holger Krag of the European Space Agency states that as of 2017 there is no binding international regulatory framework with no progress occurring at the respective UN body in Vienna.


Barriers

With the rapid development of the computer and digitalization industries, more countries and companies have engaged in space activities since the turn of the 20th century.
The tragedy of the commons ''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the ...
is an economic theory referring to a situation where maximizing self-interest through using a shared resource can finally lead to the resource degradation shared by all. Based on the theory, individuals’ rational action in space will finally lead to an irrational collective result: orbits are crowded with debris. As a
common-pool resource In economics, a common-pool resource (CPR) is a type of good consisting of a natural or human-made resource system (e.g. an irrigation system or fishing grounds), whose size or characteristics makes it costly, but not impossible, to exclude potenti ...
, the Earth's orbits, especially LEO and GEO that accommodate most satellites, are nonexcludable and
rivalry A rivalry is the state of two people or groups engaging in a lasting competitive relationship. Rivalry is the "against each other" spirit between two competing sides. The relationship itself may also be called "a rivalry", and each participant o ...
. To address the tragedy and ensure
space sustainability Space sustainability aims to maintain the safety and health of the space environment. Similar to sustainability initiatives on Earth, space sustainability seeks to use the environment of space to meet the current needs of society without compr ...
, many technical approaches have been developed. And in terms of governance mechanisms, the top-down centralized one is less suitable to tackle the complex debris problem due to the increasing number of space actors. Instead, much evidence has proved that polycentric form of governance developed by
Elinor Ostrom Elinor Claire "Lin" Ostrom (née Awan; August 7, 1933 – June 12, 2012) was an American Political science, political scientist and Political economy, political economist whose work was associated with New institutional economics, New Institutio ...
can work in space. In the process of promoting the polycentric network, there are some existing barriers needed to be dealt with.


Incomplete data of space debris

As orbital debris is a global problem affecting both spacefaring and non-spacefaring nations, it is necessary to be handled in a worldwide context. Because of the complexity and dynamics of object movements like spacecrafts, debris, meteorites, etc., many countries and regions including the United States, Europe, Russia and China have developed their space situational awareness (SSA) to avoid potential threats in space or plan actions in advance. To a certain extent, SSA plays a role in tracking space debris. In order to build a powerful SSA system, there are two prerequisites: international cooperation and exchange of information and data. However, limitations still exist in spite of the substantially improving data quality over the past decades. Some space powers are not willing to share the information that they have collected, and those, such as the U.S., that have shared the data keep parts of it secret. Instead of joining in a coordinated way, a great deal of SSA programs and national databases run parallel to each other with some overlaps, hindering the formation of a collaborative monitoring system. Some private actors are also trying to establish SSA systems. For example, the Space Data Association (SDA) formed in 2009 is a non-governmental entity. It currently consists of 21 global satellite operators and 4 executive members:
Eutelsat Eutelsat S.A. is a French satellite operator. Providing coverage over the entire European continent, the Middle East, Africa, Asia and the Americas, it is the world's third-largest satellite operator in terms of revenues. Eutelsat's satellit ...
, Inmarsat,
Intelsat Intelsat S.A. (formerly INTEL-SAT, INTELSAT, Intelsat) is a multinational satellite services provider with corporate headquarters in Luxembourg and administrative headquarters in Tysons Corner, Virginia, United States. Originally formed as In ...
and
SES SES, S.E.S., Ses and similar variants can refere to: Business and economics * Socioeconomic status * Scottish Economic Society, a learned society in Scotland * SES, callsign of the TV station SES/RTS (Mount Gambier, South Australia) * SES S.A., ...
. SDA is a non-profit platform, aiming to avoid radio interference and space collisions through pooling data from operators independently. Researchers suggest that it is essential to establish an international center for exchanging information on space debris because SSA networks do not completely equal debris tracking systems — the former ones focus more on active and threatening objects in space. And in terms of debris populations and defunct satellites, not very much operators have provided data. In a polycentric governance network, a resource that cannot be holistically monitored is less possible to be well managed. Both insufficient transnational cooperation and information sharing bring resistance to addressing the debris problem. There is still a long way to go before building a global network that covers complete data and has strong interconnection and interoperability.


Insufficient participation of private actors

With the commercialization of satellites and space, the private sector is getting more interested in space activities. For example,
SpaceX Space Exploration Technologies Corp. (SpaceX) is an American spacecraft manufacturer, launcher, and a satellite communications corporation headquartered in Hawthorne, California. It was founded in 2002 by Elon Musk with the stated goal of ...
is planning to create a network of around 12,000 small satellites that can transmit high-speed internet to any place in the world. The proportion of commercial spacecrafts has increased from 4.6% in the 1980s to 55.6% in the 2010s. Despite the high participation rate of commercial entities, UN COPUOS once deliberately excluded them from having a voice in discussions unless being formally invited by a member state. Ostrom said that the involvement of all relevant stakeholders in the rule-design and implementation process is one of the critical elements of successful governance. The exclusion of private actors largely reduces the effectiveness of the committee's role in making collective-choice arrangements that reflect the interests of all space users. The limited engagement of private actors slows down the process of addressing space debris to some degree. Ties existing between dissimilar stakeholders in the governance network offer access to diverse resources. Different competence among stakeholders can help allocate the tasks more reasonably. In that case, the expertise and experience of private operators are critical to help the world achieve space sustainability. The complementary strengths of different stakeholders enable the governance network to be more adaptable to changes and reach common goals more effectively. In recent years, many private actors have seen commercial opportunities of eliminating space debris. It is estimated that by 2022 the global market for debris monitoring and removal will generate a revenue of around $2.9 billion. For example,
Astroscale Astroscale Holdings Inc. is a private orbital debris removal company headquartered in Tokyo, Japan. The company is developing satellite end-of-life and active debris removal services to mitigate the growing and hazardous buildup of debris in ...
has contracted with European and Japanese space agencies to develop the capacity of removing orbital debris. Despite that, they are still in small quantity compared to the number of those who have placed satellites in space. Privateer Space, a Hawaiian-based startup company started by American engineer
Alex Fielding Alex Fielding is an American engineer and manager. He is the CEO and co-founder of Privateer Space with Apple co-founder Steve Wozniak. He was co-founder and CEO of robotics company Ripcord, Inc from 2014 to 2021. Biography Alex Fielding started ...
, space environmentalist Dr. Moriba Jah, and
Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...
co-founder
Steve Wozniak Stephen Gary Wozniak (; born August 11, 1950), also known by his nickname "Woz", is an American electronics engineer, computer programmer, philanthropist, inventor, and technology entrepreneur. In 1976, with business partner Steve Jobs, he c ...
, announced plans in September 2021 to launch hundreds of satellites into orbit in order to study space debris. However, the company stated it is in "stealth mode" and no such satellites have been launched. Fortunately, the current space exploration is not completely driven by competition, and there still exists a chance for dialogues and cooperation among all stakeholders in both developed and developing countries, to reach an agreement on tackling space debris and assure an equitable and orderly exploration. Besides private actors,
network governance Network governance is "interfirm coordination that is characterized by organic or informal social system, in contrast to bureaucratic structures within firms and formal relationships between them. The concepts of privatization, public private par ...
does not necessarily exclude the states from playing a role. Instead, the different functions of states might promote the governance process. To improve the polycentric governance network of space debris, researchers suggest: encourage data-sharing among different national and organizational databases at the political level; develop shared standards for data collection systems to improve interoperability; enhance the participation of private actors through involving them in national and international discussions.


Environmental concerns

The continued practice of disposing of space debris on Earth in areas such as the
spacecraft cemetery The spacecraft cemetery, known more formally as the South Pacific Ocean(ic) Uninhabited Area, is a region in the southern Pacific Ocean east of New Zealand, where spacecraft that have reached the end of their usefulness are routinely crashed. Th ...
has raised environmental concerns. Klinger states that "the environmental geopolitics of Earth and outer space are inextricably linked by the
spatial politics Spatial politics refers to the use of spatial terms to simplify and dramatize political differences and actions. Thus left-wing politics oppose right-wing politics -- after the seating habits on the left and right sides of French assemblies in th ...
of privilege and sacrifice – among people, places, and institutions". Since 1971, 273 spacecraft and satellites have been directed to Point Nemo; this number includes the
Mir Space Station ''Mir'' (russian: Мир, ; ) was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet Union and later by Russia. ''Mir'' was the first modular space station and was assembled in orbit from 1986 to&n ...
(142 tonnes) and will include the
International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ( ...
in 2024 (240 tonnes). In 2018, it was found that the water had 26 microplastic particles per cubic metre, meaning it is highly polluted. The prevalence of orbital debris has been likened to the terrestrial environmental phenomenon of "
sacrifice zone A sacrifice zone or sacrifice area (often termed a national sacrifice zone or national sacrifice area) is a geographic area that has been permanently impaired by heavy environmental alterations or economic disinvestment, often through locally unwant ...
s," which are designated geographic regions with high levels of environmental degradation. Since the 1960s, over three hundred rocket launch sites have been built globally. Among these launch sites, 17 hosted 90 launches in 2017 alone. Rocket launches affect local and global environments through the construction of necessary infrastructure, exposure of local environments to toxic residue and the dispersal of
pollutant A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oi ...
s. Rockets are the only source of direct anthropogenic emissions into the
stratosphere The stratosphere () is the second layer of the atmosphere of the Earth, located above the troposphere and below the mesosphere. The stratosphere is an atmospheric layer composed of stratified temperature layers, with the warm layers of air ...
and emit ozone depleting substances such as
nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has a ...
,
hydrogen chloride The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...
and aluminium oxide; these substances can destroy 105
ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...
molecules before depleting. Each launch showers an area concentrated within a kilometre with toxins, heavy metals, and acids. This results in localised regional
acid rain Acid rain is rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but acid ...
, plant death, fish kills, and failed
seed germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an flowering plant, angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spor ...
. Furthermore, studies on trace elements concentration in alligators, near NASA launch activities in Florida (USA), showed that over 50% of alligators had "greater than toxic levels" of trace elements in their liver. Similarly, research in
Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
,
Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
and China has found that
unsymmetrical dimethylhydrazine Unsymmetrical dimethylhydrazine (UDMH; 1,1-dimethylhydrazine, НДМГ or codenamed Geptil) is a chemical compound with the formula H2NN(CH3)2 that is used as a rocket propellant. It is a colorless liquid, with a sharp, fishy, ammonia-like smell ...
(UDMH) has
carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substan ...
ic,
mutagen In genetics, a mutagen is a physical or chemical agent that permanently changes nucleic acid, genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can ca ...
ic,
convulsant A convulsant is a drug which induces convulsions and/or epileptic seizures, the opposite of an anticonvulsant. These drugs generally act as stimulants at low doses, but are not used for this purpose due to the risk of convulsions and consequent exc ...
,
teratogenic Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related t ...
,
embryotoxic Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related t ...
and DNA damaging effects on rodents living near the
Baikonur Cosmodrome The Baikonur Cosmodrome ( kk, Байқоңыр ғарыш айлағы, translit=Baiqoñyr ğaryş ailağy, ; russian: Космодром Байконур, translit=Kosmodrom Baykonur, ) is a spaceport in an area of southern Kazakhstan leased to R ...
, Kazakhstan. It is unknown, however, at what trace concentrations these toxic effects manifest in humans or how it may
bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...
up the food chain. A lack of adequate resourcing to maintain safe, non-toxic environments makes these areas sacrifice zones and spaces of waste. The relative remoteness of these spaces makes them attractive launch sites, yet this "periphery" remain central to both their human and non-human inhabitants, who become "sacrificial".


At other celestial bodies

The issue of space debris has been raised as a mitigation challenge for missions around the Moon with the danger of increasing space debris around it. In 2022, several elements of space debris were found on Mars, ''
Perseverance Perseverance may refer to: Behaviour * Psychological resilience * Perseverance of the saints, a Protestant Christian teaching * Assurance (theology) Geography * Perseverance, Queensland, a locality in Australia * Perseverance Island, Seychelles ...
s backshell was found on the surface of Jezero Crater, and a piece of a thermal blanket that may have come from the descent stage of the rover. It is thought that on 4 March 2022, for the first time, human space debris – most likely a spent rocket body,
Long March 3C The Long March 3C (), also known as the Changzheng 3C, CZ-3C and LM-3C, is a Chinese orbital launch vehicle. It is launched from Launch Complex 2 and 3 at the Xichang Satellite Launch Center (XSLC). A three-stage rocket with two strapon liquid ...
third stage from the 2014 Chang'e 5 T1 mission – unintentionally hit the lunar surface, creating an unexpected double crater.


In popular culture

''
Until the End of the World ''Until the End of the World'' (german: Bis ans Ende der Welt; french: Jusqu'au bout du monde) is a 1991 science fiction adventure drama film directed by German filmmaker Wim Wenders. Set at the turn of the millennium in the shadow of a world ...
'' (1991) is a French sci-fi drama set under the backdrop of an out-of-control Indian nuclear satellite, predicted to re-enter the atmosphere, threatening vast populated areas of the Earth. ''
Gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...
'', a 2013 survival film directed by
Alfonso Cuaron Alphons (Latinized ''Alphonsus'', ''Adelphonsus'', or ''Adefonsus'') is a male given name recorded from the 8th century (Alfonso I of Asturias, r. 739–757) in the Christian successor states of the Visigothic kingdom in the Iberian peninsula. ...
, is about a disaster on a space mission caused by Kessler syndrome. In season 1 of ''
Love, Death & Robots ''Love, Death & Robots'' (stylized as ''LOVE DEATH + R⬮BOTS'', and represented in emoji form as ❤️❌🤖) is an adult animated anthology streaming television series created by Tim Miller and streaming on Netflix. Produced by Blur Studio ...
'' (2019), episode 11, "Helping Hand", revolves around an astronaut being struck by a screw from space debris which knocks her off a satellite in orbit. Manga and anime ''
Planetes ''Planētes'', "Wanderers", lead=yes is a Japanese hard science fiction manga written and illustrated by Makoto Yukimura. It was serialized in Kodansha's ''seinen'' manga magazine ''Morning'' between January 1999 to January 2004, with its ...
'' tells a story about a crew of Space Debris station that collects and disposes space debris.


See also

* :Derelict satellites *
Interplanetary contamination Interplanetary contamination refers to biological contamination of a planetary body by a space probe or spacecraft, either deliberate or unintentional. There are two types of interplanetary contamination: *''Forward contamination'' is the transfer ...
*
Liability Convention The Convention on International Liability for Damage Caused by Space Objects, also known as the Space Liability Convention, is a treaty from 1972 that expands on the liability rules created in the Outer Space Treaty of 1967. In 1978, the crash o ...
*
List of large reentering space debris This is a list of artificial objects reentering Earth's atmosphere by mass (see space debris). Such objects are often completely destroyed by reentry heating, but large enough objects or components can survive. Most of the objects which reent ...
* List of space debris producing events *
Long Duration Exposure Facility NASA's Long Duration Exposure Facility, or LDEF (pronounced "eldef"), was a school bus-sized cylindrical facility designed to provide long-term experimental data on the outer space environment and its effects on space systems, materials, operatio ...
*
Near-Earth object A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
*
Orbital Debris Co-ordination Working Group The Orbital Debris Co-ordination Working Group (ODCWG) is one of the working groups of the International Organization for Standardization's Technical Committee 20/Subcommittee 14 TC20/SC14 "Spacecraft Systems and Operations". History The Orbital ...
*
Project West Ford Project West Ford (also known as Westford Needles and Project Needles) was a test carried out by Massachusetts Institute of Technology's Lincoln Laboratory on behalf of the United States military in 1961 and 1963 to create an artificial ionospher ...
*
Satellite warfare Space warfare is hypothetical combat in which one or more belligerents are situated in outer space. The scope of space warfare therefore includes ''ground-to-space warfare'', such as attacking satellites from the Earth; ''space-to-space warfare ...
*
Solar Maximum Mission The Solar Maximum Mission satellite (or SolarMax) was designed to investigate Sun, Solar phenomena, particularly solar flares. It was launched on February 14, 1980. The SMM was the first satellite based on the Multimission Modular Spacecraft bus ...
*
Spacecraft cemetery The spacecraft cemetery, known more formally as the South Pacific Ocean(ic) Uninhabited Area, is a region in the southern Pacific Ocean east of New Zealand, where spacecraft that have reached the end of their usefulness are routinely crashed. Th ...
*
Space domain awareness Space domain awareness is the study and monitoring of satellites orbiting the earth. It involves the detection, tracking, cataloging and identification of artificial objects, i.e. active/inactive satellites, spent rocket bodies, or fragmentatio ...
*
Space sustainability Space sustainability aims to maintain the safety and health of the space environment. Similar to sustainability initiatives on Earth, space sustainability seeks to use the environment of space to meet the current needs of society without compr ...


References


Citations


General and cited references

* Donald Kessler (Kessler 1991)
"Collisional Cascading: The Limits of Population Growth in Low Earth Orbit"
''Advances in Space Research'', Volume 11 Number 12 (December 1991), pp. 63–66. * Donald Kessler (Kessler 2009)

8 March 2009. * Donald Kessler and Phillip Anz-Meador (March 2001)
"Critical Number of Spacecraft in Low Earth Orbit: Using Fragmentation Data to Evaluate the Stability of the Orbital Debris Environment"
Third European Conference on Space Debris. * Donald Kessler (Kessler 1981)
"Sources of Orbital Debris and the Projected Environment for Future Spacecraft"
''Journal of Spacecraft'', Volume 16 Number 4 (July–August 1981), pp. 357–60. * Donald Kessler and Burton Cour-Palais (Kessler 1978)
"Collision Frequency of Artificial Satellites: The Creation of a Debris Belt"
''Journal of Geophysical Research'', Volume 81, Number A6 (1 June 1978), pp. 2637–46. * Donald Kessler (Kessler 1971)
"Estimate of Particle Densities and Collision Danger for Spacecraft Moving Through the Asteroid Belt"
''Physical Studies of Minor Planets'', NASA SP-267, 1971, pp. 595–605. .
''Orbital Debris: A Technical Assessment''
National Academy of Sciences, 1995. . Technical. * Schefter, Jim (July 1982)
"The Growing Peril of Space Debris"
''Popular Science'', pp. 48–51.


Further reading



Center for Orbital and Reentry Debris Studies,
Aerospace Corporation The Aerospace Corporation is an American nonprofit corporation that operates a federally funded research and development center (FFRDC) in El Segundo, California. The corporation provides technical guidance and advice on all aspects of space mi ...
* ** News item summarizing the above report * Steven A. Hildreth and Allison Arnold
''Threats to U.S. National Security Interests in Space: Orbital Debris Mitigation and Removal.''
Washington, D.C.:
Congressional Research Service The Congressional Research Service (CRS) is a public policy research institute of the United States Congress. Operating within the Library of Congress, it works primarily and directly for members of Congress and their committees and staff on a c ...
, 8 January 2014. * David Leonard, "The Clutter Above", ''Bulletin of the Atomic Scientists'', July/August 2005. * Patrick McDaniel
"A Methodology for Estimating the Uncertainty in the Predicted Annual Risk to Orbiting Spacecraft from Current or Predicted Space Debris Population"
National Defense University, 1997.
"Interagency Report on Orbital Debris, 1995"
National Science and Technology Council, November 1995. * Nickolay Smirnov
''Space Debris: Hazard Evaluation and Mitigation''
Boca Raton, FL: CRC Press, 2002, . * Richard Talcott, "How We Junked Up Outer Space", ''
Astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...
'', Volume 36, Issue 6 (June 2008), pp. 40–43.
"Technical report on space debris, 1999"
United Nations, 2006. . * * Khatchadourian, Raffi, "The Trash Nebula: Millions of man-made artifacts are circling Earth. Will one of them cause a disaster?", 28 September 2020, pp. 44–52, 54–55. "By one estimate, there are a hundred million bits of debris that are a millimetre in size, a hundred million as small as a micron. We live in a corona of trash. e problem, if ignored, could destroy all the
satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioi ...
s that orbit near the Earth – a loss that would be more acutely felt as humanity increasingly relied on space." (p. 47.)


External links


Sativew – Tracking Space Junk in real time

NASA Orbital Debris Program Office




documentary film

* ttp://www.sgo.fi/~jussi/spade/ipy/index.html EISCAT Space Debris during the international polar year
Intro to mathematical modeling of space debris flux

SOCRATES: A free daily service predicting close encounters on orbit between satellites and debris orbiting Earth

A summary of current space debris by type and orbit

Space Junk
''
Astronomy Cast ''Astronomy Cast'' is an educational nonprofit podcast discussing various topics in the field of astronomy. The specific subject matter of each episode shifts from week to week, ranging from planets and stars to cosmology and mythbusting. Premie ...
'' episode No. 82, includes full transcript
Paul Maley's Satellite Page – Space debris (with photos)

Space Debris Illustrated: The Problem in Pictures

PACA: Space Debris

IEEE – The Growing Threat of Space Debris

The Threat of Orbital Debris and Protecting NASA Space Assets from Satellite Collisions

Orbital Debris

Space Age Wasteland: Debris in Orbit Is Here to Stay; Scientific American; 2012

United States Space Surveillance Network

PATENDER: GMV’S Trailblazing low-gravity space-debris capture system

Space Junk Infographic

Stuff In Space

Astria Graph
{{Authority control Global issues Space hazards Spaceflight Near-Earth objects Future problems Pollution Technology hazards Space traffic management