2001 Mars Odyssey
Artist's impression of the Mars Odyssey spacecraft
Mission typeMars orbiter
OperatorNASA / JPL
COSPAR ID2001-013A Edit this at Wikidata
SATCAT no.26734
Mission duration
  • Elapsed:
    • 23 years, 2 months and 20 days from launch
    • 22 years, 8 months and 3 days at Mars (8060 sols)
  • En route: 6 months, 17 days
  • Primary mission: 32 months (1007 sols)
  • Extended mission: 19 years, 10 months and 2 days (7052 sols) elapsed
Spacecraft properties
ManufacturerLockheed Martin
Launch mass725 kg[1]
Dry mass376.3 kilograms (830 lb)
Power750 W
Start of mission
Launch dateApril 7, 2001, 15:02:22 (2001-04-07UTC15:02:22Z) UTC[2]
RocketDelta II 7925-9.5
Launch siteCape Canaveral SLC-17A
End of mission
Last contactQ4 2025 (planned)
Orbital parameters
Reference systemAreocentric
Semi-major axis3,793.4 km (2,357.1 mi)[3]
Altitude400 km (250 mi)[3]
Period2 hours[3]
Argument of periareion[3]
Mean anomaly[3]
EpochOctober 19, 2002[3]
Mars orbiter
Orbital insertionOctober 24, 2001,
MSD 45435 12:21 AMT

2001 Mars Odyssey is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectrometers and a thermal imager to detect evidence of past or present water and ice, as well as study the planet's geology and radiation environment.[4] The data Odyssey obtains is intended to help answer the question of whether life 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 the Curiosity rover, and previously the Mars Exploration Rovers and Phoenix lander, to Earth. The mission was named as a tribute to Arthur C. Clarke, evoking the name of his and Stanley Kubrick's 1968 film 2001: A Space Odyssey.[5][6]

Odyssey was launched April 7, 2001, on a Delta II rocket from Cape Canaveral Air Force Station, and reached Mars orbit on October 24, 2001, at 02:30 UTC (October 23, 19:30 PDT, 22:30 EDT).[7]

On May 28, 2002 (sol 210), NASA reported that Odyssey's GRS instrument had detected large amounts of hydrogen, 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.[8] The orbiter also discovered vast deposits of bulk water ice near the surface of equatorial regions.[9]

By December 15, 2010, it broke the record for longest serving spacecraft at Mars, with 3,340 days of operation.[10][11] Odyssey has also served as the primary means of communications for NASA's Mars surface explorers in the past decade, up to the Curiosity rover. It currently holds the record for the longest-surviving continually active spacecraft in orbit around a planet other than Earth, ahead of the Pioneer Venus Orbiter (served 14 years[12]) and the Mars Express (serving over 20 years), at 22 years, 8 months and 3 days. As of October 2019 it is in a polar orbit around Mars with a semi-major axis of about 3,800 km or 2,400 miles. It is estimated to have enough propellant to function until the end of 2025.[13]


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 to Ares, 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-mailed Arthur 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 administrator Ed Weiler wrote to the associate administrator for public affairs recommending a name change from ARES to 2001 Mars Odyssey. Peggy Wilhide then approved the name change.[14][15]

Mission objectives

Scientific instruments

The three primary instruments Odyssey uses are the:


Summary of Mars Odyssey mission start
The spacecraft encapsulated in Delta II rocket fairing

Mars Odyssey launched from Cape Canaveral on April 7, 2001, and arrived at Mars about 200 days later on October 24. Upon arrival, the spacecraft's main engine fired[20] in order to decelerate, which allowed it to be captured into orbit around Mars. Odyssey then spent about 76 days aerobraking, using aerodynamic drag from the upper reaches of the Martian atmosphere to gradually slow down and reduce and circularize its orbit.[20] 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.[21]

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.[22]

The payload's MARIE radiation experiment stopped taking measurements after a large solar event bombarded the Odyssey 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.[23]

About 85% of images and other data from NASA's twin Mars Exploration Rovers, Spirit and Opportunity, have reached Earth via communications relay by Odyssey.[24] The orbiter helped analyze potential landing sites for the rovers and performed the same task for NASA's Phoenix mission, which landed on Mars in May 2008. Odyssey aided NASA's Mars 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.[25]

Odyssey is in a Sun-synchronous orbit,[26] 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.[27]

The orbiter's orientation is controlled by a set of three reaction 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.[28][29]

Mars Odyssey's THEMIS instrument was used to help select a landing site for the Mars Science Laboratory (MSL).[30] 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.[31] Odyssey also acted as a relay for UHF radio signals from the (MSL) rover Curiosity.[32] Because Odyssey is in a Sun-synchronous orbit,[26] it passes over Curiosity's location twice per day, enabling regular contact with Earth.[33]

On February 11, 2014, mission control accelerated Odyssey'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.[34] Those observations could yield insight about the composition of the ground and about temperature-driven processes, such as warm seasonal flows observed on some slopes, and geysers fed by spring thawing of carbon dioxide (CO2) ice near Mars' poles.[34]

On October 19, 2014, NASA reported that the Mars Odyssey Orbiter,[35] as well as the Mars Reconnaissance Orbiter[36] and MAVEN,[37] were healthy after the Comet Siding Spring flyby.[38][39]

In 2010, a spokesman for NASA's Jet Propulsion Laboratory stated that Odyssey could continue operating until at least 2016.[40] This estimate has since been extended to the end of 2025.[13]

Major discoveries

Further information: Water on Mars

By 2008, Mars Odyssey had mapped the basic distribution of water below the shallow surface.[41] The ground truth for its measurements came on July 31, 2008, when NASA announced that the Phoenix lander confirmed the presence of water on Mars,[42] as predicted in 2002 based on data from the Odyssey 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.[43]

The orbiter also discovered vast deposits of bulk water ice near the surface of equatorial regions.[9] Evidence for equatorial hydration is both morphological and compositional and is seen at both the Medusae Fossae formation and the Tharsis Montes.[9]

Mars—horizon views (video; 1:24; Odyssey orbiter; THEMIS camera; 9 May 2023)

See also


  1. ^ "2001 Mars Odyssey". NASA Space Science Data Coordinated Archive. Retrieved 2022-11-29.
  2. ^ "2001 Mars Odyssey". NASA Space Science Data Coordinated Archive. Retrieved 2022-11-29.
  3. ^ a b c d e f g h Makovsky, A.; Barbieri, A.; Tung, R. (October 2002). Odyssey Telecommunications (PDF) (Report). p. 7.
  4. ^ "Mars Odyssey Goals". NASA JPL.
  5. ^ "Mars Odyssey: Overview". JPL, CIT. Archived from the original on 2011-09-19.
  6. ^ "It's "2001 Mars Odyssey" for NASA's next trip to the red planet" (Press release). NASA. Archived from the original on 2021-04-18.
  7. ^ "2001 Mars Odyssey Quick Facts". 2001 Mars Odyssey. NASA/JPL. Retrieved 2021-01-22.
  8. ^ "January, 2008: Hydrogen Map". Lunar & Planetary Lab at The University of Arizona. Archived from the original on 2008-10-13. Retrieved 2015-06-30.
  9. ^ a b c Equatorial locations of water on Mars: Improved resolution maps based on Mars Odyssey Neutron Spectrometer data (PDF). Jack T. Wilson, Vincent R. Eke, Richard J. Massey, Richard C. Elphic, William C. Feldman, Sylvestre Maurice, Luıs F. A. Teodoroe. Icarus, 299, 148–160. January 2018.
  10. ^ "NASA's Odyssey Spacecraft Sets Exploration Record on Mars". Press Releases. JPL, NASA. December 15, 2010. Archived from the original on 2011-04-25.
  11. ^ Howell, Elizabeth (July 23, 2018). "Mars Odyssey: Record-Breaking Mission to Mars". space.com. Retrieved 2024-03-13.
  12. ^ "Pioneer Venus 1: In Depth". NASA Solar System Exploration. NASA.
  13. ^ a b "Engineers Keep an Eye on Fuel Supply of NASA's Oldest Mars Orbiter". JPL. NASA. March 15, 2023. Retrieved 2023-03-15.
  14. ^ Hubbard, Scott (2011). Exploring Mars: Chronicles from a Decade of Discovery. University of Arizona Press. pp. 149–51. ISBN 978-0-8165-2896-7.
  15. ^ "It's "2001 Mars Odyssey" for NASA's Next Trip to the Red Planet" (Press release). NASA HQ/JPL. September 28, 2000. Retrieved 2016-03-12.
  16. ^ a b c d "Objectives". mars.nasa.gov. NASA/JPL. Retrieved 2021-01-27.
  17. ^ Christensen, P. R.; Jakosky, B. M.; Kieffer, H. H.; Malin, M. C.; McSween Jr., H. Y.; Nealson, K.; Mehall, G. L.; Silverman, S. H.; Ferry, S.; Caplinger, M.; Ravine, M. (2004). "The Thermal Emission Imaging System (THEMIS) for the Mars 2001 Odyssey Mission". Space Science Reviews. 110 (1–2): 85. Bibcode:2004SSRv..110...85C. doi:10.1023/B:SPAC.0000021008.16305.94. S2CID 3629716.
  18. ^ Boynton, W.V.; Feldman, W.C.; Mitrofanov, I.G.; Evans, L.G.; Reedy, R.C.; Squyres, S.W.; Starr, R.; Trombka, J.I.; d'Uston, C.; Arnold, J.R.; Englert, P.A.J.; Metzger, A.E.; Wänke, H.; Brückner, J.; Drake, D.M.; Shinohara, C.; Fellows, C.; Hamara, D.K.; Harshman, K.; Kerry, K.; Turner, C.; Ward, M.; Barthe, H.; Fuller, K.R.; Storms, S.A.; Thornton, G.W.; Longmire, J.L.; Litvak, M.L.; Ton'chev, A.K. (2004). "The Mars Odyssey Gamma-Ray Spectrometer Instrument Suite". Space Science Reviews. 110 (1–2): 37. Bibcode:2004SSRv..110...37B. doi:10.1023/B:SPAC.0000021007.76126.15. S2CID 121206223.
  19. ^ "Profile: Dr. William Boynton". 2001 Mars Odyssey. NASA. Archived from the original on 2021-05-10. Retrieved 2021-05-10.
  20. ^ a b "NASA Facts: 2001 Mars Odyssey" (PDF). NASA. Archived (PDF) from the original on 2015-09-05.
  21. ^ "Mars Odyssey Mission Status" (Press release). NASA Jet Propulsion Laboratory. January 11, 2002.
  22. ^ "Mission Timeline – Mars Odyssey". NASA Jet Propulsion Laboratory.
  23. ^ "MARIE". 2001 Mars Odyssey. NASA. Archived from the original on 2021-05-10. Retrieved 2021-05-10.
  24. ^ NASA, JPL. "Communications Relay – Mars Odyssey". mars.nasa.gov. Retrieved 2018-10-31.
  25. ^ "Mars Odyssey Begins Overtime After Successful Mission". NASA Jet Propulsion Laboratory (JPL). Retrieved 2022-06-24.
  26. ^ a b "Mars Odyssey". NASA Science. October 24, 2001. Retrieved 2024-03-20.
  27. ^ Martinez, Carolina; Webster, Guy (June 22, 2009). "NASA's Mars Odyssey Alters Orbit to Study Warmer Ground". JPL News. Pasadena, California: JPL. Archived from the original on 2021-05-10. Retrieved 2021-05-10.
  28. ^ "Longest-Lived Mars Orbiter Is Back in Service". Status Reports. JPL. June 27, 2012. Archived from the original on 2012-07-03.
  29. ^ NASA, JPL. "Guidance, Navigation, and Control – Mars Odyssey". mars.nasa.gov. Retrieved 2018-10-31.
  30. ^ "THEMIS Support for MSL Landing Site Selection". THEMIS. Arizona State University. July 28, 2006. Archived from the original on 2006-08-14.
  31. ^ Gold, Scott (August 7, 2012). "Curiosity's perilous landing? 'Cleaner than any of our tests'". Los Angeles Times. Archived from the original on 2012-08-09.
  32. ^ "Mars Science Laboratory Landing". NASA/JPL. July 2012. Retrieved 2021-01-22.
  33. ^ Howell, Elizabeth (August 3, 2012). "How NASA's New Mars Rover Will Phone Home". Space.com. Retrieved 2024-03-20.
  34. ^ a b Staff (February 12, 2014). "NASA Moves Longest-Serving Mars Spacecraft for New Observations". Press Releases. Jet Propulsion Laboratory. Archived from the original on 2014-02-26.
  35. ^ Webster, Guy; Brown, Dwayne (October 19, 2014). "NASA's Mars Odyssey Orbiter Watches Comet Fly Near". NASA. Retrieved 2014-10-20.
  36. ^ Webster, Guy; Brown, Dwayne (October 19, 2014). "NASA's Mars Reconnaissance Orbiter Studies Comet Flyby". NASA. Retrieved 2014-10-20.
  37. ^ Jones, Nancy; Steigerwald, Bill; Webster, Guy; Brown, Dwayne (October 19, 2014). "NASA's MAVEN Studies Passing Comet and Its Effects". NASA. Retrieved 2014-10-20.
  38. ^ Webster, Guy; Brown, Dwayne; Jones, Nancy; Steigerwald, Bill (October 19, 2014). "All Three NASA Mars Orbiters Healthy After Comet Flyby". NASA. Retrieved 2014-10-20.
  39. ^ "A Comet's Brush With Mars". The New York Times. Agence France-Presse. October 19, 2014. Retrieved 2014-10-20.
  40. ^ Kremer, Ken (December 13, 2010). "The Longest Martian Odyssey Ever". Universe Today. Archived from the original on 2010-12-20.
  41. ^ "January, 2008: Hydrogen Map". Lunar & Planetary Lab at The University of Arizona. Archived from the original on 2008-10-13. Retrieved 2015-06-30.
  42. ^ "Confirmation of Water on Mars". Phoenix Mars Lander. NASA. June 20, 2008. Archived from the original on 2008-07-01.
  43. ^ "NASA's Phoenix touches, tastes Martian water". The Economic Times. Retrieved 2022-06-24.