The term Spaceguard loosely refers to a number of efforts to discover, catalogue, and study

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). ...

s (NEO), especially those that may impact Earth (

potentially hazardous objects A potentially hazardous object (PHO) is a near-Earth object – either an asteroid or a comet – with an orbit that can make close approaches to the Earth and is large enough to cause significant regional damage in the event of impact. They are ...

). Asteroids are discovered by

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...

s which repeatedly survey large areas of sky. Efforts which concentrate on discovering NEOs are considered part of the "Spaceguard Survey," regardless of which organization they are affiliated with. A number of organizations have also raised related discussions and proposals on

asteroid-impact avoidance Asteroid impact avoidance comprises the methods by which near-Earth objects (NEO) on a potential collision course with Earth could be diverted away, preventing destructive impact events. An impact by a sufficiently large asteroid or other NEOs ...

. The United Kingdom hosts the self-styled The SpaceGuard Centre which conducts astrometric research (MPC code J26) and is open to the general public daily, but it is not affiliated with or supported by any public body.

History

Arthur C. Clarke coined the term in his novel ''

Rendezvous with Rama ''Rendezvous with Rama'' is a science fiction novel by British writer Arthur C. Clarke first published in 1973. Set in the 2130s, the story involves a cylindrical alien starship that enters the Solar System. The story is told from the ...

'' (1973) where "Project Spaceguard" was the name of an

early warning system An early warning system is a warning system that can be implemented as a chain of information communication systems and comprises sensors, event detection and decision subsystems for early identification of hazards. They work together to for ...

created following a fictional catastrophic

asteroid impact An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or me ...

.Michael Paine (2000-04-26)
"Bigger Telescopes Seek Killer Asteroids"
''

Space.com Space.com is an online publication focused on space exploration, astronomy, skywatching and entertainment, with editorial teams based in the United States and United Kingdom. The website offers live coverage of space missions, astronomical discov ...

'' (accessed on 2010-06-26) This name was later adopted by a number of real life efforts to discover and study near-

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

objects. The name was used for the Survey "with the permission and encouragement of Clarke." A 1992 US Congressional study produced a "Spaceguard Survey Report"

David Morrison Lieutenant General David Lindsay Morrison (born 24 May 1956) is a retired senior officer of the Australian Army. He served as Chief of Army from June 2011 until his retirement in May 2015. He was named Australian of the Year for 2016. Early ...

(1992),
The Spaceguard Survey Report
",
NASA Studies
'' at Asteroid and Comet Impact Hazards,

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

Ames Research Center The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laborat ...

. which led to a mandate that

locate 90% of near-Earth

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

s larger than 1 km within 10 years. This is often referred to as the "Spaceguard Goal." A number of efforts which receive money through NASA are all considered to be working on the "Spaceguard Project." The effect of the impact of

Comet Shoemaker–Levy 9 Comet Shoemaker–Levy 9 ( formally designated D/1993 F2) broke apart in July 1992 and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of Solar System objects. This generated a l ...

to Jupiter in July 1994 created a greater perception of importance to the detection of near Earth objects. As David Levy stated in an interview "The giggle factor disappeared after Shoemaker-Levy 9." He was referring to the contemporary attitude that

extinction level event An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...

s were so improbable that those advocating for research for detection and possible deflection methods were only paranoid alarmists. The impact of one of its fragments created a giant dark spot on Jupiter over 12,000 km across, and was estimated to have released an energy equivalent to 6,000,000 megatons of TNT (600 times the world's nuclear arsenal). After the impact of Comet Shoemaker-Levy 9, asteroid detection programs all over the world received greater funding. The Working Group on Near-Earth Objects (WGNEO) of the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

held a workshop in 1995 entitled ''Beginning the Spaceguard Survey''Beginning the Spaceguard Survey
Vulcano Workshop (1995), IAU Working Group on Near-Earth Objects. (accessed on 2010-06-26) which led to an international organization called the

Spaceguard Foundation The Spaceguard Foundation (SGF) is a private organization based in Frascati, Italy, whose purpose is to study, discover and observe near-Earth objects (NEO) and protect the Earth from the possible threat of their collision. The foundation is non ...

. Subsequently, there have been Spaceguard associations or foundations formed in countries around the world to support the ideas of discovering and studying near-Earth objects. Generally, the Spaceguard organizations formed within individual countries are associated with the international foundation or with the NASA efforts only by name, common interests, and similar goals. The initial Spaceguard Goal was achieved, although in slightly longer than 10 years. An extension to the project gave NASA the mandate of reducing the minimum size at which more than 90% of near-Earth asteroids are known to 140 m.

Observations

The 2002 Eastern Mediterranean event, the 2002 Vitim event (Russia) and the

Chelyabinsk meteor The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural (region), Ural region in Russia on 15 February 2013 at about 09:20 Yekaterinburg Time, YEKT (03:20 Coordinated Universal Time, UTC). It was caused ...

(Russia, February 2013) were not detected in advance by any Spaceguard effort. On October 6, 2008, the 4-meter 2008 TC₃

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 micr ...

was detected by the

Catalina Sky Survey Catalina Sky Survey (CSS; obs. code: 703) is an astronomical survey to discover comets and asteroids. It is conducted at the Steward Observatory's Catalina Station, located near Tucson, Arizona, in the United States. CSS focuses on the search ...

(CSS) 1.5 meter telescope at

Mount Lemmon Mount Lemmon, with a summit elevation of , is the highest point in the Santa Catalina Mountains. It is located in the Coronado National Forest north of Tucson, Arizona, United States. Mount Lemmon was named for botanist Sara Plummer Lemmon, who ...

, and monitored until it hit the Earth the next day. New survey projects, such as the

Asteroid Terrestrial-impact Last Alert System The Asteroid Terrestrial-impact Last Alert System (ATLAS) is a robotic astronomical survey and early warning system optimized for detecting smaller near-Earth objects a few weeks to days before they impact Earth. Funded by NASA, and developed an ...

(ATLAS) program operated by the

University of Hawaii A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...

, aim to greatly increase the number of small (down to approximately 10 m) impactors that are discovered before

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 ...

—typically with days to weeks of warning, enabling evacuations of the affected areas and damage mitigation planning. This is in contrast to other surveys which focus on finding much larger (greater than 100 m) objects years to decades before any potential impacts, at times when they could potentially still be deflected away from Earth. Another short-term warning system is the NASA Scout program that came into operation in 2016. On October 19, 2017, one of the Survey telescopes,

Pan-STARRS The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical c ...

1, discovered the first interstellar asteroid, 'Oumuamua.

Issues

According to Dr. Michael F. A'Hearn, a typical mission would take too long from approval to launch if there was an emergency: Lack of a master plan and dangers of false alarms have been pointed out by Stefan Lövgren.Stefan Lovgren (2004-03-08),
Asteroid False Alarm Shows Limits of Alert Systems
''National Geographic News''. (accessed on 2010-06-26)

References

External links

Spaceguard Central Node

NASA's Near-Earth Office Program

David Morrison Tuesday, August 1, 2000 (Discovery statistics by 2000)

Saturday, February 9, 2002 (Status report by 2002)
UK Spaceguard Centre

Planetary Defense Foundation

{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Astronomical surveys Planetary defense organizations

History

Observations

Issues

See also

References

Further reading

External links