7 April

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.

It is hoped that the data Odyssey obtains will help answer the question of whether life has ever existed on Mars and create a risk-assessment of the radiation future astronauts on Mars might experience. It also acts as a relay for communications between the Mars Exploration Rovers, Mars Science Laboratory, and the Phoenix lander to Earth. The mission was named as a tribute to Arthur C. Clarke, evoking the name of 2001: A Space Odyssey.

Odyssey was launched 7 April 2001 on a Delta II rocket from Cape Canaveral Air Force Station, and reached Mars orbit on 24 October 2001, at 02:30 UTC.  It is currently in a polar orbit around Mars with an altitude of about 3,800 km or 2,400 miles.

By 15 December 2010 it broke the record for longest serving spacecraft at Mars, with 3,340 days of operation, claiming the title from NASA’s Mars Global Surveyor. It currently holds the record for the longest-surviving continually active spacecraft in orbit around a planet other than Earth, ahead of the European Space Agency’s Mars Express, at 14 years, 5 months and 13 days.

Mars Odyssey mapped the distribution of water in the surface. The ground truth for its measurements came on 31 July 2008, when NASA announced that the Phoenix lander confirmed the presence of water on Mars, 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.

Mars Odyssey’s THEMIS instrument was used to help select a landing site for the Mars Science Laboratory (MSL). 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. Odyssey now acts as a relay for UHF radio signals from the (MSL) rover Curiosity. Because Odyssey is in a sun-synchronous orbit, it consistently passes over Curiosity’s location at the same two times every day, allowing for convenient scheduling of contact with Earth.