Peter Thomas, second from left, senior research associate in the astronomy department's Center for Radiophysics and Space Research, points to the Mars Pathfinder landing site on a globe of Mars in the Space Sciences Building. Thomas and astronomy doctoral student Jeffrey Moersch were interviewed Monday by Syracuse television news reporters. Charles Harrington/University Photography
It's Christmas in July for Cornell's planetary scientists.
The treasure trove of images and data being transmitted from a microwave oven-sized robot rover on the surface of Mars is giving scientists the best information about the red planet in 20 years -- from the diversity of rocks and boulders to the red dust Martian landscape hinting of massive ancient floods.
"It's just so nice to get back there after 20 years," said Peter Thomas, senior research associate in the Cornell astronomy department's Center for Radiophysics and Space Research who studies Mars. "It's nice to be getting good data again and so much of it. I tend to look for colored rocks and how many different types of rocks there are. There probably were a wide variety of materials on the surface 2 billion years ago. They look like remnants of a flood still visible after 2 billion years."
The last time a NASA probe visited Mars was a Viking mission in 1976, in which pictures were taken from orbit and landers were placed at two different sites on the planet. But Pathfinder -- renamed the Carl Sagan Memorial Station by NASA on July 5 in honor of the late Cornell professor and Pulitzer Prize-winning author -- landed on Mars on Independence Day 1997 and has been, along with the rover Sojourner, transmitting video images and information about the soil and rocks from the first possible moment.
James Bell, a Cornell research associate in astronomy, is at NASA's Jet Propulsion Laboratory (JPL) this week to help interpret the data as part of the NASA team. "We're looking for anything out of the ordinary, in addition to basic geological information," Bell said. And they found it.
Chosen for the lander imaging team just a few months ago, Bell is helping determine what types of minerals and rocks are present on the Martian surface. The camera, a CCD video camera similar to that used by consumers for home use, is outfitted with about a dozen color filters to discriminate individual minerals. Iron oxide, for example, should be abundant because oxidation of rock is what gives Mars its red color.
Some of the rocks on the surface look as though they are fresh -- that is, they have not rusted like most of the Martian surface. "There are two possible scenarios," Bell said from the JPL on Tuesday. "One is that these rocks were erupted by volcanoes or by impact craters, and they come to the surface where they slowly oxidize. The other is that these are exposed on the surface, but the environment was very different than what it is today. Were all these 'fresh' rocks brought in by the flood, or are they all local? If they're external to the site, then they traveled quite far. The answer has very important implications for the climate history of Mars, and I wish I could tell you which one is right." He added: "This site is just spectacular. It was chosen for this reason, because we have a grab bag of different rocks. It's just spectacular, and everyone here is really up."
Last week at Cornell, Bell was looking forward to the mission. "This is really a geology mission," Bell said. "We'll look at the shape, size and color of the rocks, as well as at geologic formations and surface-atmosphere interactions. We'll be looking for whether the climate was different in the past, too, and anything else that looks interesting."
At night, scientists use the camera as a telescope, training it on stars and the Martian moons as they pass overhead. "It will be like we're astronomers on the surface of Mars," Bell said.
The camera, called the Imager for Mars Pathfinder (IMP), makes observations at various times during the day to detect any changes over the lifetime of the mission that might be attributed to the actions of frost, dust or sand deposition, erosion or other surface-atmosphere interactions. Observations of the general landscape, surface slopes and the distribution of rocks are obtained by panoramic stereo images.
For Jeffrey Moersch, a Cornell doctoral student in astronomy and space sciences, the mission is a dream come true. "I was in grade school the last time we were there," he said. "This is just spectacular. I've spent the last seven years studying Mars, and this is great."
Moersch said the images confirm a lot of the information that Viking had gleaned. "The types of terrain we see are consistent with water. But it's nice to have fresh data."
Do any of the data yield clues to whether life exists now or existed in the past? Cornell scientists say there is nothing so far that sheds light on that question, but keep in mind that this mission was designed before a Martian meteorite on Earth was found to contain what may be fossilized microbial life.
"We may know more next year," said Thomas, who already is looking forward to the next Martian probe -- Mars Global Surveyor, well on its way toward Mars, which will begin sending data back as early as September. Thomas is part of that team.
Cornell also has a high-capacity mirror site on the Internet for information and to follow the Pathfinder mission. The site, <mars.tc.cornell.edu>, can accommodate 4 million hits, or accesses, per day. The site is maintained at the Cornell Theory Center.
Also last week, the closest flyby of a spacecraft to an asteroid -- 750 miles -- shows that the asteroid is a leftover remnant from the vast cloud of space rocks that orbited the sun for billions of years and eventually formed the planets. Joseph Veverka, Cornell professor of astronomy, who is the NASA team leader for Near Earth Asteroid Rendezvous (NEAR) imaging experiment, said the 33-mile-wide asteroid, named Mathilde, is almost all dark gray-black, twice as dark as charcoal. Planets and their moons usually show color in debris thrown up from craters, but there is none on Mathilde, suggesting that it did not undergo the processes that occur on planets. Heavily cratered, Mathilde has been hit many times by flying debris and has huge chunks missing, Cornell astronomers said. Also working on that mission from Cornell are Bell, Thomas and Steven Squyres, professor of astronomy.