Is there water on Mars?
Yes, there is water on Mars, mostly frozen as ice in its polar caps and underground. Liquid water cannot last long on the surface because the air is so thin and cold.
The polar ice caps contain large amounts of water ice, covered in winter by frozen carbon dioxide. Radar from orbiting spacecraft has also found buried ice in many mid-latitude regions. NASA's Phoenix lander scraped up ice just below the surface near the north pole in 2008.
Billions of years ago, Mars was warmer and wetter. Rovers such as Curiosity and Perseverance have found dried riverbeds, ancient lake deposits and rounded pebbles shaped by flowing water. Jezero Crater, explored by Perseverance, was once a lake with a river delta.
Why water matters
Water is key to the search for past life on Mars. It would also be a vital resource for future astronauts, who could use ice for drinking water, oxygen and rocket fuel.
Did You Know?
In 2024, scientists analyzing data from NASA's InSight lander reported signs that liquid water may be trapped deep in Martian rocks, about 10 to 20 kilometers underground.