Icy Revelations from the Red Planet
Sue Smrekar: Mars Reconnaissance Orbiter has made a fortuitous discovery.
Title - Sue Smrekar, Mars Reconnaissance Orbiter Deputy Project Scientist:
Smrekar: We found water somewhat closer to the equator
than we were expecting to see it.
Title - Shane Byrne, Planetary Scientist, University of Arizona, Tucson
Byrne: We discovered several new impact craters
that dredged up or excavated ice from below the surface.
Smrekar: These craters were found between about 45 and 55 degrees north,
so that's the latitude of about Paris.
Byrne: The context camera team detects new impacts by examining
before and after images of certain portions of the surface and then looking for changes.
Usually, what they see is a dark mark that the impact has left on the surface.
Then the high-resolution camera, the HiRise camera, follows up on that observation.
Smrekar: When HIRISE went in and took an image of these small craters, they saw this very
Byrne: bright blue material that was poking out from the bottom of these craters
and it looked a lot like water ice.
Smrekar: So they took this image using their spectrometer, saw that in one of the five,
there was in fact, a signature of ice.
HiRise continued to take a series of images over several hundred days.
And what they actually were able to do is watch how the ice disappears over time.
If you take the Styrofoam lid off your cooler, here on Earth the ice starts to melt,
but on Mars it just turns into water vapor.
Byrne: And sure enough, it faded away like you would expect water ice to fade away.
So we have an idea now of how much water was available
in the Martian atmosphere in the recent past,
based on where we see ice in the subsurface today.
Smrekar: One of the great ironies about this discovery is that
several of these craters were found in the vicinity of one of the Viking landers.
And that lander had an arm that dug down into the soil looking for ice.
And what we realized from looking at the distribution of ice from these craters
Title - Mars Viking 2 Lander at Utopia Planitia (1976)
Smrekar: is that, if that lander had gone down 6 inches deeper it should've found ice.
It just stopped inches short of where it could've found ice.
I think one of the things that's really interesting about this is
that it gives us a new window into the water story on Mars.
You know, the whole Mars program has been following the water
and that this is our first insight into how water and climate
have changed on Mars over the last ten to 100-thousand years.
It gives us another piece of the puzzle to understand the climate history of Mars.
NASA's Jet Propulsion Laboratory, California Institute of Technology