The Mars Odyssey spacecraft, circling the Red Planet since its arrival there in 2001, is about to reach a milestone that will see it complete 60,000 orbits, NASA has announced.

Odyssey, named after Arthur C. Clarke's bestselling science fiction novel "2001: A Space Odyssey," arrived at Mars on Oct. 23, 2001.

Nine years later, on Dec. 15, 2010, it gained the distinction of being the longest-operating space probe ever sent to the Red Planet, a distinction it still holds today, says NASA's Jet Propulsion Laboratory in Pasadena, California.

JPL manages the Mars Odyssey Project for the space agency's Science Mission Directorate in Washington.

In additional to its scientific discoveries while orbiting Mars — most notably the detection of widespread water ice beneath the planet's surface — Odyssey acts as a vital communications relay for NASA's active rovers Curiosity and Opportunity on the Martian surface.

It is also expected to perform a similar function for future NASA and European Space Agency landers set to arrive on Mars in 2016.

"This orbital milestone is an opportunity to celebrate Odyssey's many achievements," says Jim Green, NASA's director of Planetary Science. "Odyssey will continue to help lay a foundation for the first humans to Mars in the 2030s through NASA's Journey to Mars initiative."

One key instrument operating aboard Odyssey is a visual/infrared camera that has snapped 400,000 images during the spacecraft's orbital lifetime, helping researchers create maps of much of the Red Planet's surface.

The Thermal Emission Imaging System (THEMIS), designed by Arizona State University, operates in five visual and nine infrared (heat-sensitive) "colors."

Researchers there were quick to give credit to the entire Odyssey team.

"Mars Odyssey's enduring success has let THEMIS achieve a longer run of observations than any previous instrument at Mars," says ASU geological sciences professor Philip Christensen, the instrument's principal investigator.

"THEMIS has thus provided the context for most recent Mars scientific research," he notes. "We're very grateful to the scientists, engineers and technicians who have kept the spacecraft in good health."

NASA researchers say they are confident Odyssey will provide many more years of scientific service.

"The spacecraft is in good health, with all subsystems functional and with enough propellant for about 10 more years," says Mars Odyssey project manager David Lehman at JPL.