Mars Odyssey is an orbiter carrying science experiments designed to make global observations of Mars to improve our understanding of the planet's climate and geologic history, including the search for water and evidence of life-sustaining environments.
Mars Odyssey was launched April 7, 2001 on a Delta II rocket from Cape Canaveral, Florida, and reached Mars on October 24, 2001, 0230 Universal Time (October 23, 7:30 pm PDT/ 10:30 EDT). The spacecraft's main engine fired to brake the spacecraft's speed and allowed it to be captured into orbit around Mars. Odyssey used a technique called "aerobraking" that gradually brought the spacecraft closer to Mars with each orbit. By using the atmosphere of Mars to slow down the spacecraft in its orbit rather than firing its engine or thrusters, Odyssey was able to save more than 200 kilograms (440 pounds) of propellant.
Aerobraking ended in January, and its science mapping mission began in February 2002. The primary science mission continued through August 2004 and Odyssey is currently in its extended mission. Odyssey also serves as a communications relay for the Mars Exploration Rovers (Spirit and Opportunity) and future missions.