But according to a recently released study, the amount of water was far greater than anyone thought.
Scientists at the University of Nevada created a synthetic version of whitlockite, complete with hydrogen.
A new study found that a mineral - merellite - found in Martian meteorites may not be proof of a dry Mars at all. Using a synthetic version of whitlockite, they began conducting shock compression experiments on it created to simulate the conditions under which meteorites are ejected from Mars. The mineral isn't found on Earth but merrillite crystals are often found in Martian meteorites.
The researchers found that up to 36 percent of the synthetic whitlockite was converted to merrillite at the plate-sample interface. The researchers at the United States Space Agency think that a sufficiently high power magnetic shield if launched into space will be serving as a replacement for the Red Planet's magnetosphere that is lost.
They found that shocked whitlockite dehydrates and turns into - merrillite.
'If even a part of merrillite had been whitlockite before, it changes the water budget of Mars dramatically, ' said Oliver Tschauner of the University of Nevada, Las Vegas (UNLV).
The new study hints that ancient Marsmay have been very wet indeed. This means that the planet had one of the key building blocks for life on Earth.
The planet could even have been covered in water - we don't know.
The transformation of whitlockite into merrillite during the experiments was a simulation: Scientists were able to recreate the pressures and temperatures comparable to those of a meteorite impact for only about 100 billionths of a second, approximately one-tenth to one-hundredth as long as an actual meteorite impact. Such strikes may therefore have produced "almost full conversion" to merrillite, Tschauner said in the same statement.
Minerals from Martian meteorites appear to be indicating that the planet once had an abundance of water, making Mars much wetter than what scientists have assumed so far. It is to be noted that other teams of researchers have come up with evidence of liquid water flowing on Mars now.
"The only missing link now is to prove that [merrillite] had, in fact, really been Martian whitlockite before", Tschauner added. "We have to go back to the real meteorites and see if there had been traces of water". NASA hopes to conduct the first step in this process with their Mars 2020 Rover, which will collect samples and leave them in a cache for future retrieval.
How does one identify a meteorite from Mars, anyway?
"Thus, significant whitlockite on Mars would mean more available phosphorus in aqueous environments for any potential prebiotic or biotic reactions", the researchers wrote in the new study, which was published online Monday (March 6) in the journal Nature Communications.
For years now, scientists have understood that Mars was once a warmer, wetter place.