The exploration of microbes in space

The exploration of microbes in space

In the current search for extraterrestrial life, imagine the day scientists discover life on a new planet. Then imagine finding out that those life forms actually originated on Earth.

With every spacecraft that leaves Earth, millions of microbes try to hitch a ride into outer space. NASA hopes to launch a Mars Sample Return Mission in the future, and preventing cross-contamination of Mars and the Earth in such a mission would be a top priority.
Watchful From the Start
Back contamination was the main concern when the planetary protection program primary began. After the Soviet Union commenced space exploration with the launching of the first Earth satellite Sputnik in 1957, the International Council for Science recognized the Committee on Space Research (COSPAR) to support international space research. One of its responsibilities was the planetary protection program.

The 1967 Outer Space Treaty formally outlined global guidelines for any nation engaging in space exploration. It stated that any activities in outer space, including the moon and other planetary bodies, must be carried out in a manner that avoids biological contamination.

Though the scientific community is expected to act responsibly in exploring new frontiers, Larry Esposito, professor of astrophysical and planetary sciences at the University of Colorado, Boulder, feels that back contamination is ultimately more important.

“The greatest dangers are back contamination even though the probability might be lower,” says Esposito. “The fact is that we're living on the Earth and determining our livelihoods, and we're part of the ecological (system), which could potentially be affected by back contamination.”
In current times, frontward contamination also has become a main concern, particularly with the exploration of Mars and the potential for finding life there.

In March of this year, astronauts on the International Space Station conducted the LOCAD-PTS Exploration experiment, the first test of planetary protection technology. This involved swabbing the astronauts’ gloves with a high-tech Q-tip and testing that Q-tip for microbes. The astronauts found almost no bacteria but they found glucan, a marker for fungi, at 15 sites.

Verification of Life
Even with the rigorous cleaning procedures currently in place, millions of microbes still get launched from Earth. “When searching for life, we don't want to have a false positive,” explains Esposito. “That would puzzle identification of life on another planet or location.”

For identification of potential alien life, NASA has an inventory of samples collected on previous missions (like Viking) to which new life forms can be compared. Conley says current DNA-based testing methods allow scientists to rule out the possibility that extraterrestrial life forms did not create on Earth. This means that scientists expect alien life to have DNA different from any known organism on Earth (if they have DNA at all).

As astrobiologists continue the quest for life in other worlds, safeguarding the environment here on Earth and elsewhere in the universe remains a main concern.

“We're concerned about life everywhere, and we don't want to pollute or invade other locations with Earth life,” says Esposito. “In the same way, we don't want to infect life on Earth with species from other planets.”