POLITICAL SCENE

September 1997

NASA's Geology Lesson on Mars

Everybody has been writing about the Mars Pathfinder mission, and that is precisely why I am too. Geology received more news coverage in July than it gets in most years, thanks to the success of Pathfinder and its roving geochemist Sojourner. Great credit goes to the engineers who designed Pathfinder and brought it bouncing to a safe landing at Ares Vallis, but the mission was at heart a geologic expedition.
My purpose is twofold. The first is to encourage geoscientists to embrace Pathfinder and take advantage of public interest in the geology of this neighboring planet to explain more about our own. After all, how often does the word "geology" appear in front-page Washington Post headlines or lead off the nightly network news? Indeed, the Post called Sojourner "the first mobile geologist on Mars."
The second is to point out the erosion in some long-held conventional wisdom about the space program -- namely, that manned missions are necessary to generate public support. In the five days after Pathfinder's Fourth of July landing, the mission's web site set a record for the Web's busiest site ever, registering 150 million hits. At a time when mammoth projects such as the international space station are increasingly crowding out scientific missions, Pathfinder's popularity should help to convince NASA that low-cost robotic missions will serve them well in space certainly, but also back home.

A Geology Mission

With its protective air bags (no children or small adults please!), Pathfinder was able to drop into a more geologically interesting spot than the Viking landers in the 1970s; the latter were confined to smooth landing sites, a tactic that was advantageous from an engineering standpoint but did little for geology. Chosen to maximize the diversity of rock types to be sampled by the rover, the Pathfinder landing site sits downstream from the mouth of the Ares and Tiu Valles catastrophic outflow channels, which drained highlands to the south. According to Pathfinder chief scientist Matthew Golombek, the site appears comparable to the Ephrata Fan and Channelled Scablands in eastern Washington state, which formed from the catastrophic failure of the ice dam that formed glacial Lake Missoula.
Pathfinder's web site offers images of these geologic surface features and news of Sojourner's exploits and the mission's scientific findings. One click brings the viewer to the results of the rover's Alpha Proton X-ray Spectrometer -- its "nose" which can determine elemental compositions. From that information, geoscientists will infer petrology and mineralogy of rocks and surface materials.
In the case of "Barnacle Bill," the first boulder tested, the analysis showed a high percentage of silicates (58 percent) and a composition that was inferred to be one-third quartz, one-third feldspar, and one-third orthopyroxene -- a composition not of basalt as expected, but like the more highly evolved andesite. Newspaper accounts made much of the fact that this rock type takes its name from the Andes Mountains (even if a few referred to it as a mineral).
The Pathfinder mission was designed to study geologic processes and surface-atmosphere interaction with an array of cameras and sensors in addition to Sojourner's spectrometer. What sort of questions will Pathfinder answer? We should learn more about the primary differentiation and early evolution of crustal materials, weathering processes on Mars, near- surface stratigraphy, Martian soil mechanics, and other fundamental geoscience concerns.
All of this geologic research sounds almost too good to be true at a time when NASA is otherwise turning away from the solid earth sciences. The budget-busting International Space Station makes only the barest mention of geoscience applications in its mission plans. Even Mission to Planet Earth, which originally called for studies of stratigraphy and tectonics, has become almost entirely an investigation of global climate change.

Keeping the Dream Alive for a Song

Not only will Pathfinder -- now renamed the Sagan Memorial Station -- and Sojourner see more than the Viking landers, the mission also cost less than one-tenth what the Viking project did two decades ago. Begun in 1993, Mars Pathfinder is the second in a new generation of NASA projects designed to be "inexpensive" (several hundred million dollars rather than several billion) and "quick" (about three years to develop). The lower cost means higher risk but also a chance to apply cutting-edge technology.
No matter how cheap these missions become, however, they are still caught in a budget squeeze created by the far more expensive manned space program. Why do we put men and women into space when robotic missions clearly are a far more cost- effective way to acquire data and expand the frontiers of knowledge? The argument has run that manned missions are necessary because Congress and the public would lose interest if we deleted the human factor. One hundred million web site hits later, it is time to question that assumption.
In a New York Times editorial, physicist Bob Park pointed out that while the Mars Pathfinder web site was racking up its record number of hits, astronauts on a more expensive space shuttle mission were still "in the upper reaches of [Earth's] atmosphere, ... dodging the garbage left behind by hundreds of previous missions." Cosmonauts on the Mir space station were just trying to stay alive. In the Washington Post, an article with images of distant Martian peaks was juxtaposed with one on the cosmonauts' efforts to fix Mir's damaged science module. The space shuttle has become routine, and people have not gone beyond Earth's outer atmosphere in decades. This fall is the 25th anniversary of the Apollo 17 mission, when geologist Harrison "Jack" Schmitt became the last man to walk on the moon.
It would be wishful thinking, however, to suggest that the success of this one mission will slow the space station juggernaut. Aside from the issue of publicity, there are policy considerations involved as the Clinton administration seeks to keep Russian scientists engaged in constructive space work in exchange for ending practices like exporting advanced rocket gear to developing countries.

A Chance To Shine

Pathfinder may not change NASA's priorities, but it can certainly help us increase public understanding of the geosciences. In the March 1997 issue of Geotimes, paleontologist Dale Springer reviewed geology coverage in general interest magazines, reporting that dinosaurs and fossils grabbed the lion's share of attention. She argued that all geoscientists can use this interest in paleontology to educate the public about geology. Now the coverage of Mars provides a similar opportunity to translate public interest into public understanding.
How different are the two? I was recently contacted by a legal publication about the implications of Sojourner's quartz discovery for staking mining claims on Mars! We clearly have some explaining to do.