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To Earth and Back | Big Picture Science
Catharine Conley - NASA planetary protection officer
"That's exactly the question that needs ...
"That's exactly the question that needs to be addressed early in the process," said Catharine Conley, NASA's planetary protection officer.
On Space Shuttle Columbia's final ...
On Space Shuttle Columbia's final mission, it had onboard an experiment coordinated by Catherine Conley, a biologist with NASA's Ames Research Center, now the agency's planetary protection officer.
After the shuttle was destroyed reentering the Earth's atmosphere, the nematode cultures contained in the experiment were recovered still alive.
What the accident demonstrated is that not only can microbial life survive in space; it can survive entry into the Earth's atmosphere.
Now evidence indicates that billions of years ago, Mars had water and atmospheric conditions that could, theoretically, have supported life.
Meteor strikes have meanwhile caused serial ejections of material from Earth to Mars and from Mars to Earth, meaning it's possible (possible) that microbial life actually originated on Mars, which subsequently became inhospitable to it, and landed from there on Earth.
If we do find microbial life on Mars, then, Conley
said, "... it could look like us.
"It's like looking for stars when ...
"It's like looking for stars when the sun's out," says NASA's Catharine Conley.
For the past 10 years at NASA
has had the difficult, sometimes unappreciated job of keeping Mars clean.
She is the head of the Office of Planetary Protection, which is tasked with preventing alien organisms from getting loose in Earth's ecosystem, as well as keeping humans from inadvertently seeding other planets with terrestrial life.
While spacecraft are more complex today than they were during the disco era, Conley
says it's still perfectly feasible to design rovers and landers that can tolerate high heat.
"For Mars missions, the biggest challenge is that the mission planners and designers choose not to include the heat-tolerance requirements up front, and it costs a lot more if you have to add those functions later," she
Studies conducted a decade ago suggested that late design changes for heat tolerance would add $100 million to the price tag of a mission.
says, the cost per mission gets cheaper as the space agency becomes more adept at designing heat-resistant hardware.
From the perspective of planetary protection, Conley
is also concerned about terrestrial organisms that can absorb water from the air.
recalls fieldwork she
did in the Atacama Desert in Chile, which is one of the driest places on Earth, with less than 0.04 inch of rain a year.
Even in this dessicated place, she
found life: photosynthetic bacteria that had made a home in tiny chambers within halite salt crystals.
There's a small amount of water retained inside the halite and, at night, it cools down and condenses both on the walls of the chambers and on the surface of the organisms that are sitting there.
also warns that water contaminated with Earth microbes could pose serious problems if astronauts ever establish a base on Mars
Most current plans call for expeditions that rely on indigenous resources to sustain astronauts and reduce the supplies they would need to haul from Earth.
What if, for example, an advance mission carried certain types of bacteria known to create calcite when exposed to water?
If such bacteria could survive on Mars
says, future explorers prospecting for liquid water instead might find that underground aquifers have been turned into cement.
If we do succeed in keeping Mars
clean for future human explorers, there isn't much we can do to prevent contamination caused by the humans themselves.
"Leaks happen, mistakes happen, things get broken," says Conley
, though, the possibility of a meteor exchange only strengthens the argument for keeping Mars clean.
"It becomes more difficult and more important to prevent Earth contamination if Mars life is related to Earth life," Conley
NASA Highlights At American Association For The Advancement Of Science Annual Meeting - Metro Machine Inc
Cassie Conley, planetary protection officer, NASA Headquarters