Now Mars Express has made the first direct detection of a chemical signature of the water ice at the south pole. Officials said today they had essentially seen the vapors of water at the surface.
"You look at the picture, look at the fingerprint and say this is water ice," said Allen Moorehouse of European Space Agency. "This is the first time it's been detected on the ground. This is the first direct confirmation."
The images were captured by the satellite's Omega imager, a combined camera and spectrometer that divides light into its components, like a prism and analyzes the chemicals involved in producing the light.
Jean-Pierre Bibring of the Space Astrophysics Institute of Orsay, France, one of Omega's developers, said the instrument's ability to read the spectral "signature" of water and carbon dioxide ice has laid to rest any doubt.
At a press briefing in Darmstadt, Germany, Bibring said that up to now, "relatively thin evidence has been presented as a reality. Here we have the [water] molecule itself that we can see from Omega's ability to reveal the composition of the solids and gases on the Mars surface. I wouldn't call it a discovery."
In a bit of international sparring, some NASA scientists said the finding was expected and confirmed what was known.
Photo evidence too
The European orbiter also returned a new high-resolution image of a channel called the Reull Vallis. Scientists suspect it might have been formed long ago by flowing water, but some researchers say other material -- perhaps carbon dioxide, lava or muddy mixtures -- could have created the many channels on the red planet.
The designer of Mars Express' High-Resolution Stereo Camera says the new image shows dry channels where water once flowed. In an interview, Gerhard Neukum of Germany's Free University of Berlin said it is too early to determine the composition of the black-colored substance at the bottom of the now dry river beds.
"These images' black areas are not shadows," Neukum said of the first pictures captured by the orbiter on Jan. 15. "It is material that was deposited at the bottom of these rivers."
Asked how he could be certain that the winding gashes in Mars' surface were in fact river beds, he said: "There is no other phenomena that we know of that would produce these effects. It is fair to say we are sure this is evidence of once-flowing water on the surface of Mars."
Neukum also said the colors of the images produced by the stereo camera is as realistic as possible and are not enhanced to provide additional details. "What you are seeing is real," he said.
advertisement
