NASA’s Mars Reconnaissance Orbiter (MRO) launched in 2005 has helped scientists determine that Mars had surface water as recently as 2 billion years ago. Previous studies had concluded that water on Mars evaporated about 3 billion years ago and this new find reduces that timeline significantly.
The findings were published last month in AGU Advances. The team made the discovery by studying chloride salt deposits that were left behind as ice water evaporated. The salt deposits also provide the first mineral evidence for the presence of liquid water on Mars.
Water flowed on Mars longer than previously thought… by a billion years! 😮 The findings come from Mars Reconnaissance Orbiter data that indicates Martian surface water left behind salt minerals as recently as 2 billion years ago. https://t.co/7heAUxxmsT pic.twitter.com/Ho6HefSV88
— NASA JPL (@NASAJPL) January 26, 2022
The team used data from an instrument named Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the MRO spacecraft. They also used the Context Camera and High-Resolution Imaging Science Experiment (HiRISE) color camera onboard the spacecraft to map the extent of chloride salts across Mars’ southern hemisphere.
They write that the salts were found in depressions that were once home to shallow ponds.
“What is amazing is that after more than a decade of providing high-resolution image, stereo, and infrared data, MRO has driven new discoveries about the nature and timing of these river-connected ancient salt ponds,” said corresponding author Bethany L. Ehlmann in a release.
“Part of the value of MRO is that our view of the planet keeps getting more detailed over time,” said Leslie Tamppari, the mission’s deputy project scientist at NASA Jet Propulsion Laboratory. “The more of the planet we map with our instruments, the better we can understand its history.”