Mars 2001 Odyssey:
Mars Odyssey used a process
called aerobraking, the spacecraft skimmed the surface of the
Mars' atmosphere 332 times over
nearly three months to slow down. The procedure saved more than 200
kilograms (440 pounds) of fuel, which allowed NASA to launch it on a smaller - and less
expensive - Delta II 7925 launch vehicle. Aerobraking was also used on the
Mars Global Surveyor
mission.
After a little orbital fine tuning, Odyssey began a 917 day mission to map the Martian surface and search for signs of water ice on the surface.
Visit the Mars 2001 Odyssey Website