POLITICAL SCENE | September 1997 |
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.
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