WASHINGTON —
A dozen years after it was found in Antarctica, a martian meteorite provided
a team of researchers from NASA and Stanford University
intriguing
evidence that primitive life forms might once have existed on Mars.
The potato-shaped ALH 84001, a 4-billion-year-old meteorite found in Antarctica in 1984,
contained fossilized traces of carbonate materials that the scientists said provided telltale signs of organic processes that might be explained by the presence on ancient Mars of
simple bacteria-like organisms
.
In August 1996 NASA’s Human Exploration and Development of Space group, which included experts from academia and industry and later from the European, Russian and Japanese space agencies, were forced to accelerate their plans for a press conference when word of the finding leaked out, causing a global media frenzy.
Almost immediately, exobiologists divided themselves into groups of
skeptics and believers with a scattering of agnostics.
Believers noted that only organic, or
carbon-based,
life performs the sorts of processes necessary to create the type of microfossils seen in the meteorite.
However,
skeptics argued that
ALH 84001 could have been
contaminated after it
reached
Earth.
Others
said that non-biological processes could have been responsible for the makeup of ALH 84001.
Eleven years later, the true nature of ALH 84001
remains controversial.
One thing that unites the believers and skeptics, though, is a strong consensus that
the best way to settle the argument is to take samples on Mars and perhaps even conduct a Mars sample return mission.
U.S. President
Bill Clinton, who announced the finding, urged NASA to
“put its full intellectual power and technological prowess behind the search for further evidence of life on Mars.”
Since that time there has been a renewed surge in NASA Mars missions with the successful deployment of the Mars Global Surveyor, Mars Pathfinder and the Mars Rovers, and the not-so-successful Mars Polar Lander and its soon-to-be-launched successor the Mars Phoenix Lander. Even the European Space Agency successfully has deployed Mars Express and is planning ExoMars.
Recently, however, talk about the Mars sample return mission has been circulating.
Alan Stern,
NASA’s associate administrator for the Science Mission Directorate, during a July 10 conference call reported in the July 23 issue of Space News
estimated a Mars sample return mission would launch from 2018-2020 at a cost of $3 billion to $4 billion. Such a huge drain on finances
might require NASA to skip one of the launch windows for Mars missions that occur every other year, something many scientists oppose.
Whether
it finds definitive proof for or against life on the red planet, the Mars sample return mission likely will provide for one of science’s biggest moments.
