NASA: New evidence suggesting water on Mars found (PHOTOS)

New findings are offering prospect of water on Mars, an issue that has been puzzling scientists for long time now.

Traces of water on Mars are under a thin varnish of iron oxide, or rust, similar to conditions found on desert rocks in California's Mojave Desert, NASA said in a statement on Friday.

According to NASA scientists, many more outcrops of carbonates that form mainly in large water bodies have been spotted on Mars surface. These patches are more in number than originally expected.

It's possible that an important clue, the presence of carbonates, has largely escaped the notice of investigators trying to learn if liquid water once pooled on the Red Planet, Janice Bishop, a planetary scientist at NASA's Ames Research Center at the SETI Institute at Moffett Field, California, said.

The new findings that appeared in the Friday July 1, online edition of the International Journal of Astrobiology, were similar to observations provided by NASA's Mars Reconnaissance Orbiter (MRO) spacecraft, which revealed “the strongest carbonate signature ever found” on an ancient region of Mars called Nili Fossae.

Another spacecraft for Mars mission called Spirit identified a small carbonate outcrop at a crater called Gusev in 2010, scientists said.

More recently, NASA's newest and most capable rover, the Mars Science Laboratory Curiosity, which is schedule to launch in November, will study whether Mars had environmental conditions favorable for supporting microbial life.

NASA’s findings in the past have also heightened speculations about the potential for microbial life on Mars. In 2006, Mars Global Surveyor spacecraft, which began orbiting Mars in 1997, provided images of two gullies on Mars that suggest water carried sediment through them.

In 2008, laboratory tests aboard NASA's Phoenix Mars Lander identified water in a soil sample.

As scientists continue to launch various Mars missions to know if life existed on the Red Planet, here are a few pictures from NASA’s past Mars expeditions suggesting evidence of water on the Martian surface: