Discovery that Mars may once have nurtured life is spurring the world's space agencies to rethink their strategies.
This could speed up the timetable for a robotic mission to return a sample from Mars - planned for around 2005. It may also strengthen the case for eventually sending astronauts to the Red Planet.
Such missions would be costly and technically demanding. But Daniel Goldin, administrator of the National Aeronautics and Space Administration (NASA), says he is convinced that they can be accomplished without straining national space budgets if done on an international basis.
To facilitate this strategic reassessment, President Clinton has asked Vice President Al Gore to convene a space summit in November. Mr. Goldin says he believes his counterparts around the world will be eager to attend. He notes that the discovery of what may be Martian fossils has aroused "an unbelievable excitement around the world."
Gone is the reluctance to consider a sample return mission to Mars - let alone a manned Mars mission - as worthwhile projects in an era of budget cutbacks. The newly announced discovery promises to give space planners a sound scientific basis from which to assess the value of such missions.
Everett Gibson of NASA's Johnson Space Center in Houston summed up that value in a phrase - "ground truth."
He explained that even if further research confirms that a meteorite from Mars contains evidence of ancient life, it will not tell how abundant or varied that life actually was. It won't indicate if that life continued to evolve and may be present on Mars today. The only way to find out is to go there and look.
At a press conference at NASA's Washington headquarters Wednesday, Goldin said space planners have to be tough-minded. "We want to be science-driven" and not propose missions just because they are emotionally appealing, he said. But if well-validated research indicates there is knowledge about life to be found on Mars, he said, "we will go with the American people" and ask Congress for needed funds.
NASA's current plans envision 10 robotic Mars missions over the next decade, beginning with two launches this fall. They will include orbiters that scan the planet, landers that examine the surface, and rovers that scoot about studying rock formations. Other nations are participating in some of these missions.
NASA also is coordinating with other space agencies - especially the European Space Agency and the Russian Space Agency - to ensure that national Mars research programs complement rather than compete with each other.
NASA planners now want to review the new scientific results, Goldin says, and see if the agency should change some of the objectives of its 10-year plan. For example, they may want to accelerate the sample return mission.
The agency is ready for "bold" action, Goldin said. That could even include sending astronaut scientists to Mars if on-site studies seem to be the best way to gain valuable knowledge. But he emphasized that whatever new priorities are assigned, they will be backed up by solid scientific reasons. Given such compelling reasons for an ambitious mission, Goldin added that he believes "it will be a worldwide mission" in which many nations will want to join.
Meanwhile, the immediate priority for exobiologists is to verify the new findings. Chemical residues and what look like microfossils in a meteorite found in Antarctica have convinced a small NASA-led research team that they probably are the remains of Martian microbes that lived billions of years ago.
But as William Schopf of the University of California at Los Angeles (but not a member of the NASA-led research team) said at Wednesday's press conference, there is no conclusive proof to tell whether these are real fossils or merely "foolers."
It will take more research, including looking for definite biological structures such as cell walls, to decide that issue. NASA promises to give qualified outside scientists samples of the meteorite to examine.
Wesley Huntress, NASA associates administrator for space science, acknowledged this necessity. He said that, at this point, NASA's attitude toward the findings is one of "skeptical optimism."