New research suggests ingredients for life have been present in the martian subsurface for much of the planet's history, they said.
Scientists have been studying McLaughlin Crater, one of many martian craters where impacting meteors have acted like natural probes, bringing up rocks from far beneath the surface.
Spectrometer data on those rocks from NASA's Mars Reconnaissance Orbiter shows many of the rocks contain clays and minerals whose chemical make-up has been altered by water, an essential element to support life, NASA said in a release Monday.
Much of life on Earth consists of simple microorganisms hidden in rocks beneath the surface and scientists have suggested the same may be true for Mars.
"We don't know how life on Earth [first] formed but it is conceivable that it originated underground, protected from harsh surface conditions that existed on early Earth," Joseph Michalski, planetary geologist at the Natural History Museum in London, said.
That same may have taken place on the Red Planet, researchers said.
"This research has demonstrated how studies of Earth and Mars depend on each other," John Parnell, geochemist at the University of Aberdeen in Scotland, said. "It is what we have observed of microbes living below the continents and oceans of Earth. They allow us to speculate on habitats for past life on Mars, which in turn show us how life on the early Earth could have survived."