''Stardust'' was a 385-kilogram

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 ...

space probe A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ...

launched by

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 ...

on 7 February 1999. Its primary mission was to collect dust samples from the coma of

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...

Wild 2, as well as samples of

cosmic dust Cosmic dust, also called extraterrestrial dust, star dust or space dust, is dust which exists in outer space, or has fallen on Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 micrometers). Larger particles are c ...

, and return them to Earth for analysis. It was the first

sample return mission A sample-return mission is a spacecraft mission to collect and return samples from an extraterrestrial location to Earth for analysis. Sample-return missions may bring back merely atoms and molecules or a deposit of complex compounds such as lo ...

of its kind. En route to comet Wild 2, it also flew by and studied the asteroid

5535 Annefrank 5535 Annefrank (), provisional designation , is a stony Florian asteroid and suspected contact binary from the inner asteroid belt, approximately 4.5 kilometers in diameter. It was used as a target to practice the flyby technique that the Star ...

. The primary mission was successfully completed on 15 January 2006 when the sample return capsule returned to Earth. A mission extension, codenamed ''NExT'', culminated in February 2011 with ''Stardust'' intercepting comet

Tempel 1 Tempel 1 (official designation: 9P/Tempel) is a periodic Jupiter-family comet discovered by Wilhelm Tempel in 1867. It completes an orbit of the Sun every 5.5 years. Tempel 1 was the target of the ''Deep Impact'' space mission, which photogra ...

, a

small Solar System body A small Solar System body (SSSB) is an object in the Solar System that is neither a planet, a dwarf planet, nor a natural satellite. The term was first defined in 2006 by the International Astronomical Union (IAU) as follows: "All other objects, ...

previously visited by '' Deep Impact'' in 2005. ''Stardust'' ceased operations in March 2011. On 14 August 2014, scientists announced the identification of possible

interstellar dust Cosmic dust, also called extraterrestrial dust, star dust or space dust, is dust which exists in outer space, or has fallen on Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 micrometers). Larger particles are c ...

particles from the ''Stardust'' capsule returned to Earth in 2006.

Mission background

History

Beginning in the 1980s, scientists began seeking a dedicated mission to study a comet. During the early 1990s, several missions to study

comet Halley Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–79 years. Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and thus the on ...

became the first successful missions to return close-up data. However, the US cometary mission,

Comet Rendezvous Asteroid Flyby The Comet Rendezvous Asteroid Flyby (CRAF) was a cancelled plan for a NASA-led exploratory mission designed by the Jet Propulsion Laboratory during the mid-to-late 1980s and early 1990s, that planned to send a spacecraft to encounter an asteroid ...

, was canceled for budgetary reasons. In the mid-1990s, further support was given to a cheaper, Discovery-class mission that would study comet Wild 2 in 2004. ''Stardust'' was competitively selected in the fall of 1995 as a NASA Discovery Program mission of low-cost with highly focused science goals. Construction of ''Stardust'' began in 1996, and was subject to the maximum contamination restriction, level 5

planetary protection Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions. Planetary protection reflec ...

. However, the risk of interplanetary contamination by alien life was judged low, as particle impacts at over 1,000 miles per hour, even into aerogel, were believed to be terminal for any known microorganism. Comet Wild 2 was selected as the primary target of the mission for the rare chance to observe a long-period comet that has ventured close to the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. The comet has since become a short period comet after an event in 1974, where the orbit of Wild 2 was affected by the gravitational pull of

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

, moving the orbit inward, closer to the Sun. In planning the mission, it was expected that most of the original material from which the comet formed would still be preserved. The primary science objectives of the mission included: *Providing a flyby of a comet of interest (Wild 2) at a sufficiently low velocity (less than 6.5 km/s) such that non-destructive capture of comet dust is possible using an aerogel collector. *Facilitating the intercept of significant numbers of interstellar dust particles using the same collection medium, also at as low a velocity as possible. *Returning as many high-resolution images of the comet coma and nucleus as possible, subject to the cost constraints of the mission. The spacecraft was designed, built and operated by Lockheed Martin Astronautics as a Discovery-class mission in Denver, Colorado. JPL provided mission management for the NASA division for mission operations. The principal investigator of the mission was Dr. Donald Brownlee from the University of Washington.

Spacecraft design

The spacecraft bus measured in length, and in width, a design adapted from the SpaceProbe deep space bus developed by Lockheed Martin Astronautics. The bus was primarily constructed with graphite fiber panels with an aluminum honeycomb support structure underneath; the entire spacecraft was covered with polycyanate, Kapton sheeting for further protection. To maintain low costs, the spacecraft incorporated many designs and technologies used in past missions or previously developed for future missions by the Small Spacecraft Technologies Initiative (SSTI). The spacecraft featured five scientific instruments to collect data, including the ''Stardust'' Sample Collection tray, which was brought back to Earth for analysis.

Attitude control and propulsion

The spacecraft was

three-axis stabilized Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle/satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, et ...

with eight 4.41 N hydrazine

monopropellant Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with bipro ...

thrusters, and eight 1- Newton thrusters to maintain

attitude control Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle ...

(orientation); necessary minor propulsion maneuvers were performed by these thrusters as well. The spacecraft was launched with 80 kilograms of propellant. Information for spacecraft positioning was provided by a star camera using FSW to determine attitude (stellar compass), an inertial measurement unit, and two sun sensors.

Communications

For communicating with the

Deep Space Network The NASA Deep Space Network (DSN) is a worldwide network of American spacecraft communication ground segment facilities, located in the United States (California), Spain (Madrid), and Australia (Canberra), that supports NASA's interplanetary ...

, the spacecraft transmitted data across the

X-band The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approxi ...

using a parabolic

high-gain antenna A directional antenna or beam antenna is an antenna which radiates or receives greater power in specific directions allowing increased performance and reduced interference from unwanted sources. Directional antennas provide increased performanc ...

, medium-gain antenna (MGA) and low-gain antennas (LGA) depending on mission phase, and a 15-watt

transponder In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight trans ...

design originally intended for the ''Cassini'' spacecraft.

Power

The probe was powered by two

solar arrays A photovoltaic system, also PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and c ...

, providing an average of 330 watts of power. The arrays also included

Whipple shield The Whipple shield or Whipple bumper, invented by Fred Whipple, is a type of hypervelocity impact shield used to protect crewed and uncrewed spacecraft from collisions with micrometeoroids and orbital debris whose velocities generally range be ...

s to protect the delicate surfaces from the potentially damaging cometary dust while the spacecraft was in the coma of Wild 2. The solar array design was derived primarily from the Small Spacecraft Technology Initiative (SSTI) spacecraft development guidelines. The arrays provided a unique method of switching strings from series to parallel depending on the distance from the Sun. A single nickel–hydrogen () battery was also included to provide the spacecraft with power when the solar arrays received too little sunlight.

Computer

The computer on the spacecraft operated using a

radiation-hardened Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation ( particle radiation and high-energy electromagnetic radiation), especially for environ ...

RAD6000 The RAD6000 radiation-hardened single-board computer, based on the IBM RISC Single Chip CPU, was manufactured by IBM Federal Systems. IBM Federal Systems was sold to Loral, and by way of acquisition, ended up with Lockheed Martin and is ...

32-bit processor card. For storing data when the spacecraft was unable to communicate with Earth, the processor card was able to store 128 megabytes, 20% of which was occupied by the flight system software. The system software is a form of

VxWorks VxWorks is a real-time operating system (or RTOS) developed as proprietary software by Wind River Systems, a wholly-owned subsidiary of Aptiv. First released in 1987, VxWorks is designed for use in embedded systems requiring real-time, determi ...

, an

embedded operating system An embedded operating system is an operating system for embedded computer systems. Embedded operating systems are computer systems designed to increase functionality and reliability for achieving a specific task. Resource efficiency comes at the ...

developed by

Wind River Systems Wind River Systems, also known as Wind River (trademarked as Wndrvr), is an Alameda, California–based company, subsidiary of Aptiv PLC. The company develops embedded system and cloud software consisting of real-time operating systems software, ...

Scientific instruments

Sample collection

Comet and interstellar particles are collected in ultra low density aerogel. The

tennis racket A racket, or racquet, is a sports implement used for striking a ball or shuttlecock in games such as squash, tennis, racquetball, badminton and padel. In the strictest sense a racket consists of a handled frame with an open hoop across which a ...

-sized collector tray contained ninety blocks of aerogel, providing more than 1,000 square centimeters of surface area to capture

cometary A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena are ...

and interstellar dust grains. To collect the particles without damaging them, a

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ta ...

-based solid with a porous,

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

-like structure is used in which 99.8 percent of the volume is empty space. Aerogel has the density of

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...

, another silicon-based solid to which it may be compared. When a particle hits the aerogel, it becomes buried in the material, creating a long track, up to 200 times the length of the grain. The aerogel was packed in an aluminium grid and fitted into a Sample Return Capsule (SRC), which was to be released from the spacecraft as it passed Earth in 2006. To analyze the aerogel for interstellar dust, one million photographs will be needed to image the entirety of the sampled grains. The images will be

distributed Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

to home computer users to aid in the study of the data using a program titled, Stardust@home. In April 2014, NASA reported they had recovered seven particles of interstellar dust from the aerogel.

''Stardust'' microchip

''Stardust'' was launched carrying two sets of identical pairs of square silicon

wafers A wafer is a crisp, often sweet, very thin, flat, light and dry biscuit, often used to decorate ice cream, and also used as a garnish on some sweet dishes. Wafers can also be made into cookies with cream flavoring sandwiched between them. They ...

. Each pair featured engravings of well over one million names of people who participated in the public outreach program by filling out internet forms available in late 1997 and mid-1998. One pair of the microchips was positioned on the spacecraft and the other was attached to the sample return capsule.

Mission profile

Launch and trajectory

''Stardust'' was launched at 21:04:15 UTC on 7 February 1999, by the National Aeronautics and Space Administration from Space Launch Complex 17A at the

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

in Florida, aboard a Delta II 7426 launch vehicle. The complete burn sequence lasted for 27 minutes bringing the spacecraft into a heliocentric orbit that would bring the spacecraft around the

and past

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 ...

for a gravity assist maneuver in 2001, to reach asteroid

in 2002 and comet Wild 2 in 2004 at a low flyby velocity of 6.1 km/s. In 2004, the spacecraft performed a course correction that would allow it to pass by Earth a second time in 2006, to release the Sample Return Capsule for a landing in Utah in the

Bonneville Salt Flats The Bonneville Salt Flats are a densely packed salt pan in Tooele County in northwestern Utah. A remnant of the Pleistocene Lake Bonneville, it is the largest of many salt flats west of the Great Salt Lake. It is public land managed by the Bur ...

. During the second encounter with Earth, the Sample Return Capsule was released on Jan 15, 2006. Immediately afterwards, ''Stardust'' was put into a "divert maneuver" to avoid entering the atmosphere alongside the capsule. Under twenty kilograms of propellant remained onboard after the maneuver. On 29 January 2006, the spacecraft was put in hibernation mode with only the solar panels and receiver active, in a 3-year heliocentric orbit that would return it to Earth vicinity on 14 January 2009. A subsequent mission extension was approved on 3 July 2007, to bring the spacecraft back to full operation for a flyby of comet Tempel 1 in 2011. The mission extension was the first to revisit a

and used the remaining propellant, signaling the end of the useful life for the spacecraft.

Encounter with Annefrank

At 04:50:20 UTC on 2 November 2002, ''Stardust'' encountered asteroid 5535 Annefrank from a distance of . The solar phase angle ranged from 130 degrees to 47 degrees during the period of observations. This encounter was used primarily as an engineering test of the spacecraft and ground operations in preparation for the encounter with comet Wild 2 in 2003.

Encounter with Wild 2

At 19:21:28 UTC, on 2 January 2004, ''Stardust'' encountered Comet Wild 2 on the sunward side with a relative velocity of 6.1 km/s at a distance of . The original encounter distance was planned to be , but this was changed after a safety review board increased the closest approach distance to minimize the potential for catastrophic dust collisions. The relative velocity between the comet and the spacecraft was such that the comet actually overtook the spacecraft from behind as they traveled around the Sun. During the encounter, the spacecraft was on the Sunlit side of the nucleus, approaching at a solar phase angle of 70 degrees, reaching a minimum angle of 3 degrees near closest approach and departing at a phase angle of 110 degrees. The AutoNav software was used during the flyby. During the flyby the spacecraft deployed the Sample Collection plate to collect dust grain samples from the coma, and took detailed pictures of the icy

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...

New Exploration of Tempel 1 (NExT)

On 19 March 2006, ''Stardust'' scientists announced that they were considering the possibility of redirecting the spacecraft on a secondary mission to image Comet Tempel 1. The comet was previously the target of the ''Deep Impact'' mission in 2005, sending an impactor into the surface. The possibility of this extension could be vital for gathering images of the impact crater which ''Deep Impact'' was unsuccessful in capturing due to dust from the impact obscuring the surface. On 3 July 2007 the mission extension was approved and renamed ''New Exploration of Tempel 1'' (NExT). This investigation would provide the first look at the changes to a comet nucleus produced after a close approach to the Sun. NExT also would extend the mapping of Tempel 1, making it the most mapped comet nucleus to date. This mapping would help address the major questions of comet nucleus geology. The flyby mission was expected to consume almost all of the remaining fuel, signaling the end of the operability of the spacecraft. The AutoNav software (for autonomous navigation) would control the spacecraft for the 30 minutes prior to encounter. The mission objectives included the following:

Primary objectives

*Extend the current understanding of the processes that affect the surfaces of comet nuclei by documenting the changes that have occurred on comet Tempel 1 between two successive perihelion passages, or orbits around the Sun. *Extend the geologic mapping of the nucleus of Tempel 1 to elucidate the extent and nature of layering, and help refine models of the formation and structure of comet nuclei. *Extend the study of smooth flow deposits, active areas and known exposure of water ice. ''Secondary objectives'' *Potentially image and characterize the crater produced by Deep Impact in July 2005, to better understand the structure and mechanical properties of cometary nuclei and elucidate crater formation processes on them. *Measure the density and mass distribution of dust particles within the coma using the Dust Flux Monitor Instrument. *Analyze the composition of dust particles within the coma using the Comet and Interstellar Dust Analyzer instrument.

Encounter with Tempel 1

At 04:39:10 UTC on 15 February 2011, ''Stardust-NExT'' encountered Tempel 1 from a distance of . An estimated 72 images were acquired during the encounter. These showed changes in the terrain and revealed portions of the comet never seen by ''Deep Impact''. The impact site from ''Deep Impact'' was also observed, though it was barely visible due to material settling back into the crater.

End of extended mission

On 24 March 2011 at approximately 23:00 UTC, ''Stardust'' conducted a burn to consume its remaining fuel. The spacecraft had little fuel left and scientists hoped the data collected would help in the development of a more accurate system for estimating fuel levels on spacecraft. After the data had been collected, no further antenna aiming was possible and the transmitter was switched off. The spacecraft sent an acknowledgement from approximately away in space.

Sample return

On 15 January 2006, at 05:57 UTC, the Sample Return Capsule successfully separated from ''Stardust''. The SRC re-entered the Earth's atmosphere at 09:57 UTC, with a velocity of , the fastest reentry speed into Earth's atmosphere ever achieved by a human-made object. The capsule followed a drastic reentry profile, going from a velocity of Mach 36 to subsonic speed within 110 seconds. Data in the simulation agrees with readings by the airborne observation team monitoring the reentry, available at Archived a
Ghostarchive
and th
Wayback Machine
Peak

deceleration In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by t ...

was 34 '' g'', encountered 40 seconds into the reentry at an altitude of 55 km over

Spring Creek, Nevada Spring Creek is a census-designated place (CDP) in central Elko County, in northeastern Nevada in the western United States. It mainly serves as a bedroom community for the businesses and industries in and around the nearby city of Elko. It is pa ...

. The phenolic-impregnated carbon ablator (PICA) heat shield, produced by Fiber Materials Inc., reached a temperature of more than 2,900 °C during this steep reentry. The capsule then parachuted to the ground, finally landing at 10:12 UTC at the

Utah Test and Training Range The Utah Test and Training Range (UTTR) is a Department of Defense military testing and training area located in Utah's West Desert, approximately west of Salt Lake City, Utah. UTTR is currently the largest contiguous block of over-land superson ...

, near the U.S. Army

Dugway Proving Ground Dugway Proving Ground (DPG) is a U.S. Army facility established in 1942 to test biological and chemical weapons, located about southwest of Salt Lake City, Utah, United States, and south of the Utah Test and Training Range. Location Dugway P ...

. The capsule was then transported by military aircraft from Utah to

Ellington Air Force Base Ellington Field Joint Reserve Base is a joint installation shared by various active component and reserve component military units, as well as aircraft flight operations of the National Aeronautics and Space Administration (NASA) under the aegis ...

Houston Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 i ...

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

, then transferred by road in an unannounced convoy to the Planetary Materials Curatorial facility at Johnson Space Center in Houston to begin analysis.

Sample processing

The sample container was taken to a

clean room A cleanroom or clean room is an engineered space, which maintains a very low concentration of airborne particulates. It is well isolated, well-controlled from contamination, and actively cleansed. Such rooms are commonly needed for scientif ...

with a cleanliness factor 100 times that of a hospital operating room to ensure the interstellar and comet dust was not contaminated. Preliminary estimations suggested at least a million

microscopic The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale be ...

specks of dust were embedded in the aerogel collector. Ten particles were found to be at least 100

micrometer Micrometer can mean: * Micrometer (device), used for accurate measurements by means of a calibrated screw * American spelling of micrometre The micrometre ( international spelling as used by the International Bureau of Weights and Measures; ...

s (0.1 mm) and the largest approximately 1,000 micrometers (1 mm). An estimated 45

impacts were also found on the sample collector, which resided on the back side of the cometary dust collector. Dust grains are being observed and analyzed by a volunteer team through the citizen science project, Stardust@Home. The combined mass of the harvested sample was approximately 1 mg. In December 2006, seven papers were published in the scientific journal ''

Science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...

'', discussing initial details of the sample analysis. Among the findings are: a wide range of

organic compounds In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The s ...

, including two that contain biologically usable

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

; indigenous

aliphatic hydrocarbons In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated, like hexane, o ...

with longer chain lengths than those observed in the diffuse interstellar medium; abundant amorphous silicates in addition to crystalline silicates such as

olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...

and pyroxene, proving consistency with the mixing of

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

and interstellar matter, previously deduced

spectroscopic Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...

ally from ground observations; hydrous silicates and carbonate minerals were found to be absent, suggesting a lack of aqueous processing of the cometary dust; limited pure carbon (

CHON CHON is a mnemonic acronym for the four most common elements in living organisms: carbon, hydrogen, oxygen, and nitrogen. The acronym CHNOPS, which stands for ''c''arbon, ''h''ydrogen, ''n''itrogen, ''o''xygen, ''p''hosphorus, ''s''ulfur, r ...

) was also found in the samples returned; methylamine and ethylamine was found in the aerogel but was not associated with specific particles. In 2010, Dr. Andrew Westphal announced that Stardust@home volunteer Bruce Hudson found a track (labeled "I1043,1,30") among the many images of the aerogel that may contain an interstellar dust grain. The program allows for any volunteer discoveries to be recognized and named by the volunteer. Hudson named his discovery "Orion". Stardust certisfication

In April 2011, scientists from the

University of Arizona The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory. T ...

discovered evidence for the presence of liquid water in comet

Wild 2 Comet 81P/Wild, also known as Wild 2 (pronounced "vilt two") ( ), is a comet named after Swiss astronomer Paul Wild, who discovered it on January 6, 1978, using a 40-cm Schmidt telescope at Zimmerwald, Switzerland. For most of its 4.5 billion ...

. They have found iron and

copper sulfide Copper sulfides describe a family of chemical compounds and minerals with the formula CuxSy. Both minerals and synthetic materials comprise these compounds. Some copper sulfides are economically important ores. Prominent copper sulfide mineral ...

minerals that must have formed in the presence of water. The discovery shatters the existing paradigm that comets never get warm enough to melt their icy bulk. In the spring of 2014, the recovery of particles of interstellar dust from the Discovery program's Stardust mission was announced. The Stardust samples are currently available for everyone to identify after completing the training at Berkeley webpage.

Spacecraft location

The return capsule is currently located at the National Air and Space Museum in

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

It began exhibition there on 1 October 2008, the 50th anniversary of the establishment of NASA. The return capsule is displayed in sample collection mode, alongside a sample of the aerogel used to collect samples.

Results

The comet samples show that the outer regions of the early

were not isolated and were not a refuge where interstellar materials could commonly survive. The data suggest that high-temperature inner Solar System material formed and was subsequently transferred to the Kuiper belt. ;Glycine In 2009 it was announced by

that scientists had identified one of the fundamental chemical building blocks of life in a comet for the first time:

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid ( carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinog ...

, an amino acid, was detected in the material ejected from comet Wild 2 in 2004 and captured by the ''Stardust'' probe. Glycine has been detected in meteorites before and there are also observations in interstellar gas clouds, but the ''Stardust'' find is described as a first in cometary material. Isotope analysis indicates that the

Late Heavy Bombardment The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, at a time corresponding to the Neohadean and Eoarchean eras on Earth. According to the hypot ...

included cometary impacts after the Earth coalesced but before life evolved. Carl Pilcher, who leads NASA's Astrobiology Institute commented that "The discovery of glycine in a comet supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare."