A NASA spacecraft is celebrating a major milestone today: 20 years in orbit around Mars. It’s the longest-operating Mars mission in history.

Mars Odyssey launched on April 7th, 2001. [launch audio: 3, 2, 1, we have ignition, and liftoff of a Delta II rocket carrying NASA on an odyssey back to Mars...] At launch, it was called 2001 Mars Odyssey in honor of the movie and novel “2001: A Space Odyssey.”

The craft entered orbit around Mars on October 23rd. It then spent months using a technique known as aerobraking to dip into the planet’s upper atmosphere and sculpt its final orbit.

Mars Odyssey’s instruments have mapped the entire Martian surface. They’ve also mapped the composition of the surface. Among other things, they’ve revealed salt, clay, and other compounds that formed in watery environments. The findings indicate that Mars was once much warmer and wetter than it is today — and perhaps even a comfortable home for life.

The orbiter also has detected vast layers of water ice buried beneath the red dirt all across the planet. Some of those deposits might someday provide drinking water, oxygen, and rocket fuel for human explorers.

Odyssey’s pictures have helped scientists pick out landing sites for Mars landers and rovers. And the craft has served as a relay station for those missions. It continues its work today — two decades after entering orbit around the Red Planet.

Tomorrow: a two-toned “walnut” at Saturn.
 

Script by Damond Benningfield