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 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.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).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. The orbiter also discovered vast deposits of bulk water ice near the surface of equatorial regions.By December 15, 2010, it broke the record for longest serving spacecraft at Mars, with 3,340 days of operation. 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) and the Mars Express (serving over 17 years), at 20 years and 5 months. As of 2019 October it is in a polar orbit around Mars with a semi-major axis of about 3,800 km or 2,400 miles. It has enough propellant to function until 2025.