NASA planetary protection officer suggests loosening limits on exploring Mars for life

The twin Viking spacecraft landed on Mars in 1976. They were cleaned to a level required to explore habitable regions. – NASA

Is there life on the surface of Mars? The clock is ticking on scientists’ window to solve that long-standing question before astronauts—and the microbes that live on them—contaminate the planet. Today, at a meeting in Washington, D.C., of NASA’s planetary science advisory committee, the agency’s new planetary protection officer raised the possibility of opening up a few of the planet’s most promising regions to more aggressive exploration.

Just a few weeks into the job, Lisa Pratt, formerly a geomicrobiologist at Indiana University in Bloomington, has signaled that she wants the office to be open to the notion that a degree of contamination might be necessary to explore several of the planet’s most habitable spots. Previously, the office has served as a watchdog to prevent the contamination of Mars and other planets with microbes from Earth, and vice versa. But now, time is pressing, given NASA’s long-term goals, Pratt says. “No matter what we do, the minute we’ve got humans in the area we’ve got a less pristine, less clean state,” Pratt said at the meeting. “Let’s hope we know before the humans get there, one way or the other, if there is an ecosystem at or near the surface.”

Although no region of Mars is banned for exploration, international treaties set the allowable levels of microbial contamination on robotic spacecraft destined for other planetary environments. Some scientists say it is too costly to meet the sterilization requirements to explore the potentially warm and wet “special regions” on Mars that are most likely to harbor microbes. Only the 1970s Viking landers achieved the cleanliness necessary to explore a special region. A growing number of scientists have argued that the agency needs to rethink its plans, as Sciencereported last year.

Late last year, longtime Planetary Protection Officer Cassie Conley, who favored strict enforcement standards, left NASA after an agency reorganization forced her to reapply for her job. Some Mars scientists hoped that a new officer could start a fresh conversation. Pratt, who led the Mars Exploration Analysis Group from 2013 to 2016, seems to be open to one. The likelihood of human exploration, she said at the meeting, “forces us to begin—and it’s already happening—an international conversation.”

“How do we designate,” she continued, “a few, a very small number, but a few special places on Mars [where] we can get in now with rovers and landers and do a better job asking and addressing questions of—is there present-day near-surface life on Mars? We can’t just declare every interesting place off the table. Because that means the first time we’ll know anything is when we’ve got humans there.”





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