Conley emphasized that the Curiosity assembly team and technicians did an excellent job of keeping Curiosity cleaner than any robot that NASA' s sent to Mars since the Viking lander in the 1970s.
Still, the decision to not keep the drill bits ultra-clean shows the process needs to be fixed, Conley said.
"It would have been better for them to check with me before they opened the box of bits to confirm that it was okay … rather than trying to ask for it afterwards," she said. "In this case it was fine. But for future missions we want to make sure that they ask beforehand."
The Mars Science Laboratory is not a life-detection mission. Rather, it will study whether the Gale Crater area of Mars has evidence of past and present habitable environments.
"Direct life detection is inherently difficult, some would argue currently impossible, because there is no uniform agreement on life," said Scott Hubbard, the former "Mars Czar" for NASA Headquarters in Washington.
Hubbard is now a professor in the Department of Aeronautics and Astronautics at Stanford University, Stanford, Calif., and author of the new book "Exploring Mars — Chronicles from a Decade of Discovery," published by the University of Arizona Press.
"There is no mathematical expression for life as there is gravity … only a series of attributes such as complexity, reproduction, metabolism, responsiveness and so on," Hubbard told SPACE.com. "We don't have a 'Star Trek' tricorder that says 'It's alive, Jim'."
Mars sample return
On-the-spot detection of life is difficult, underscoring the need to return to Earth well-selected samples from the Red Planet for analysis in a lab, Hubbard noted.
There are three reasons for pushing forward on a Mars return sample effort, he said: The best laboratory equipment can be employed, much of which cannot be reduced to spacecraft size; many labs and many scientists can be utilized to cross-check each other with alternate techniques; and discoveries can be followed and rechecked years later with new tools and techniques and hypotheses.
"The treaty-type agreements on planetary protection specify very rigorous levels of cleanliness to prevent forward and backward contamination," Hubbard said. "Spacecraft going to potential habitable zones on Mars must be cleaned to an amazing degree, even sterilized. Samples returned to Earth will be treated as if they were highly infectious until demonstrated otherwise."
Price tag estimates for a "Sample Receiving Facility" here on Earth have ranged as high as $300 million, Hubbard said. "Nevertheless, I think it is all worth it to find out 'Are we alone?'… 'Did life ever arise on Mars?'" he said.
Leonard David has been reporting on the space industry for more than five decades. He is a winner of this year's National Space Club Press Award and a past editor-in-chief of the National Space Society's Ad Astra and Space World magazines. He has written for SPACE.com since 1999.
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