Ten years ago, NASA’s quest to find evidence of water on Mars’ surface took off, with the launch of its Mars Reconnaissance Orbiter (MRO) spacecraft on August 12, 2005.

Forty thousand orbits and 250 terabytes of data later, the MRO spacecraft has been an unqualified success.

“[The MRO spacecraft] has found evidence of diverse watery environments on early Mars, some more habitable than others,” said project scientist Rich Zurek of NASA’s Jet Propulsion Laboratory in Pasadena, California.

“MRO has discovered that Mars’ south polar cap holds enough buried carbon-dioxide ice to double the planet’s current atmosphere if it warmed.”

The polar ice caps on Mars grow and recede with the seasons. Layered areas near the poles suggest that the planet’s climate has changed more than once.

In 2008, NASA’s Phoenix Mars lander was the first mission to touch water ice in the Martian arctic. Phoenix also observed precipitation (snow falling from clouds), as confirmed by Mars Reconnaissance Orbiter.

Although Mars’ current cold temperatures and thin atmosphere do not allow surface liquid water to exist for long, unraveling the story of water on Mars is important to unlocking its climate history, and thus the evolution of all the planets. Water is an essential ingredient for life as we know it. Evidence of long-term past or present water on Mars holds clues about whether Mars could ever have been a habitat for life

After ten years in operation, MRO remains an extremely robust mission. Every week, it returns more data than the all other active Mars missions combined.

“Even after more than 40,000 orbits, the mission remains exciting, with new challenges such as taking close-up images of a passing comet last year and supporting next year’s InSight landing,” said Kevin Gilliland, spacecraft engineer for the mission at Lockheed Martin Space Systems in Denver.