NASA's longest serving Martian orbiter, the Mars Odyssey spacecraft, has just achieved a historic milestone by completing its 60,000th orbit of the Red Planet. As a cornerstone of the agency's Mars Exploration Program, Odyssey has travelled an impressive 888 million miles (1.43 billion km) since arriving in orbit on October 24, 2001. Over the course of its operational life, the spacecraft has transformed how we see Mars, providing us with 208,240 images from its Thermal Emission Imaging System (THEMIS) alone.
Arguably Odyssey's most notable discovery was the existence of large quantities of water ice deposits beneath the surface of the Red Planet. The probe is also carrying out vital observations which will inform crew protection in a manned mission to Mars by monitoring radiation levels as a part of its Radiation Environment Experiment.
Odyssey has also provided the highest-resolution global map of Mars and in 2014, the spacecraft was tasked with documenting the flyby of the comet Siding Spring as it passed within 88,000 miles (139,500 km) of the planet.
Odyssey is still going strong, and with propellent reserves estimated to last another 10 years, the agency is far from done exhausting the probe's scientific potential. Odyssey will maintain its duties as a communications relay for NASA ground based assets, while an orbital shift will allow the spacecraft to monitor conditions in the Martian atmosphere as the morning Sun strikes the Red Planet.
"This orbital milestone is an opportunity to celebrate Odyssey’s many achievements," said 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."