 Artist's impression of theMars Odyssey spacecraft | |
| Mission type | Mars orbiter |
|---|---|
| Operator | NASA /JPL |
| COSPAR ID | 2001-013A |
| SATCATno. | 26734 |
| Website | mars |
| Mission duration |
|
| Spacecraft properties | |
| Manufacturer | Lockheed Martin |
| Launch mass | 725 kg[1] |
| Dry mass | 376.3 kilograms (830 lb) |
| Power | 750 W |
| Start of mission | |
| Launch date | April 7, 2001, 15:02:22 (2001-04-07UTC15:02:22Z) UTC[1] |
| Rocket | Delta II 7925-9.5 |
| Launch site | Cape CanaveralSLC-17A |
| Contractor | Boeing |
| End of mission | |
| Last contact | Q4 2025 (planned) |
| Orbital parameters | |
| Reference system | Areocentric |
| Regime | Sun-synchronous |
| Semi-major axis | 3,793.4 km (2,357.1 mi)[2] |
| Eccentricity | 0.0 |
| Altitude | 400 km (250 mi)[2] |
| Inclination | 93.064°[2] |
| Period | 2 hours[2] |
| RAAN | 34.98°[2] |
| Argument of periareion | 0°[2] |
| Mean anomaly | 0°[2] |
| Epoch | October 19, 2002[2] |
| Mars orbiter | |
| Orbital insertion | October 24, 2001, MSD 45435 12:21AMT |
 | |
2001 Mars Odyssey is arobotic spacecraftorbiting theplanetMars. The project was developed byNASA, and contracted out toLockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to usespectrometers and athermal imager to detect evidence of past or presentwater and ice, as well as study theplanet's geology and radiation environment.[3] The dataOdyssey obtains is intended to help answer the question of whetherlife once existed on Mars and create a risk-assessment of the radiation that future astronauts on Mars might experience. It also acts as a relay for communications between theCuriosity rover, and previously theMars Exploration Rovers andPhoenix lander, toEarth. The mission was named as a tribute toArthur C. Clarke, evoking the name of his andStanley Kubrick's 1968 film2001: A Space Odyssey.[4][5]
Odyssey was launched April 7, 2001, on aDelta II rocket fromCape Canaveral Air Force Station, and reached Mars orbit on October 24, 2001, at 02:30UTC (October 23, 19:30PDT, 22:30EDT).[6] As of March 2025, it is still collecting data, and is estimated to have enough propellant to function until the end of 2025.[7] It currently holds the record for the longest-surviving continually active spacecraft in orbit around a planet other than Earth, ahead of thePioneer Venus Orbiter (served 14 years[8]) and theMars Express (serving over 20 years), at 24 years and 30 days. As of October 2019[update] it is in apolar orbit around Mars with a semi-major axis of about 3,800 km or 2,400 miles.
On May 28, 2002 (sol 210), NASA reported thatOdyssey's GRS instrument had detected large amounts ofhydrogen, a sign that there must be ice lying within a meter of the planet's surface, and proceeded to map the distribution of water below the shallow surface.[9] The orbiter also discovered vast deposits of bulk water ice near the surface of equatorial regions.[10]
Odyssey has also served as the primary means of communications for NASA's Mars surface explorers in the past decade, up to theCuriosity rover.
In August 2000, NASA solicited candidate names for the mission. Out of 200 names submitted, the committee chose Astrobiological Reconnaissance and Elemental Surveyor, abbreviated ARES (a tribute toAres, the Greek god of war). Faced with criticism that this name was not very compelling, and too aggressive, the naming committee reconvened. The candidate name "2001 Mars Odyssey" had earlier been rejected because of copyright and trademark concerns. However, NASA e-mailedArthur C. Clarke in Sri Lanka, who responded that he would be delighted to have the mission named after his books, and he had no objections. On September 20, NASA associate administratorEd Weiler wrote to the associate administrator for public affairs recommending a name change from ARES to2001 Mars Odyssey. Peggy Wilhide then approved the name change.[11][12]
The three primary instrumentsOdyssey uses are the:
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Mars Odyssey launched fromCape Canaveral on April 7, 2001, and arrived at Mars about 200 days later on October 24. Upon arrival, the spacecraft's main engine fired[17] in order to decelerate, which allowed it to be captured into orbit around Mars.Odyssey then spent about 76 daysaerobraking, usingaerodynamic drag from the upper reaches of the Martian atmosphere to gradually slow down and reduce and circularize its orbit.[17] By planning to use the atmosphere of Mars to slow the spacecraft in its orbit rather than firing its engine or thrusters,Odyssey did not need an additional 200 kilograms (440 lb) of propellant on board. This reduction in spacecraft weight allowed the mission to be launched on a Delta II 7925 launch vehicle, rather than a larger, more expensive launcher.[18]
Aerobraking ended in January 2002, and Odyssey began its science mapping mission on February 19, 2002.Odyssey's original, nominal mission lasted until August 2004, but repeated mission extensions have kept the mission active.[19]
The payload's MARIE radiation experiment stopped taking measurements after a large solar event bombarded theOdyssey spacecraft on October 28, 2003. Engineers believe the most likely cause is that a computer chip was damaged by a solar particle smashing into the MARIE computer board.[20]
About 85% of images and other data from NASA's twinMars Exploration Rovers,Spirit andOpportunity, have reached Earth via communications relay byOdyssey.[21] The orbiter helped analyze potential landing sites for the rovers and performed the same task for NASA'sPhoenix mission, which landed on Mars in May 2008.Odyssey aided NASA'sMars Reconnaissance Orbiter, which reached Mars in March 2006, by monitoring atmospheric conditions during months when the newly arrived orbiter used aerobraking to alter its orbit into the desired shape.[22]
Odyssey is in aSun-synchronous orbit,[23] which provides consistent lighting for its photographs. On September 30, 2008 (sol 2465) the spacecraft altered its orbit to gain better sensitivity for its infrared mapping of Martian minerals. The new orbit eliminated the use of the gamma ray detector, due to the potential for overheating the instrument at the new orbit.[24]
By December 15, 2010, it broke the record for longest serving spacecraft at Mars, with 3,340 days of operation.[25][26]
The orbiter's orientation is controlled by a set of threereaction wheels and a spare. When one failed in June 2012, the fourth was spun up and successfully brought into service. Since July 2012,Odyssey has been back in full, nominal operation mode following three weeks of 'safe' mode on remote maintenance.[27][28]
Mars Odyssey's THEMIS instrument was used to help select a landing site for theMars Science Laboratory (MSL).[29] Several days before MSL's landing in August 2012,Odyssey's orbit was altered to ensure that it would be able to capture signals from the rover during its first few minutes on the Martian surface.[30]Odyssey also acted as a relay for UHF radio signals from the (MSL) roverCuriosity.[31] BecauseOdyssey is in aSun-synchronous orbit,[23] it passes overCuriosity's location twice per day, enabling regular contact with Earth.[32]
On February 11, 2014, mission control acceleratedOdyssey's drift toward a morning-daylight orbit to "enable observation of changing ground temperatures after sunrise and after sunset in thousands of places on Mars". The orbital change occurred gradually until November 2015.[33] Those observations could yield insight about the composition of the ground and about temperature-driven processes, such aswarm seasonal flows observed on some slopes, andgeysers fed by spring thawing of carbon dioxide (CO2) ice near Mars's poles.[33]
On October 19, 2014, NASA reported that theMars Odyssey Orbiter,[34] as well as theMars Reconnaissance Orbiter[35] andMAVEN,[36] were healthy after theComet Siding Spring flyby.[37][38]
In 2010, a spokesman for NASA's Jet Propulsion Laboratory stated thatOdyssey could continue operating until at least 2016.[39] This estimate has since been extended to the end of 2025.[7]
By 2008,Mars Odyssey had mapped the basic distribution of water below the shallow surface.[40] The ground truth for its measurements came on July 31, 2008, when NASA announced that thePhoenix lander confirmed the presence of water on Mars,[41] as predicted in 2002 based on data from theOdyssey orbiter. The science team is trying to determine whether the water ice ever thaws enough to be available for microscopic life, and if carbon-containing chemicals and other raw materials for life are present.[42]
The orbiter also discovered vast deposits of bulk water ice near the surface of equatorial regions.[10] Evidence for equatorial hydration is both morphological and compositional and is seen at both theMedusae Fossae formation and theTharsis Montes.[10]
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