Saturday, June 07, 2008


Stowaways Could Ruin Mars Missions, so says a story from It's a little more mundane than it sounds: some scientists are concerned that the decontamination process of the probes prior to launch may not be thorough enough; as a result, the explorations may provide false readings.

But what if: the probes were actually seeding life to other planets?

Before I fly off into speculation, a little bit about the science first. The element in question is Adenosine Triphosphate (ATP), the molecule responsible for transporting energy through the cells of all terrestrial organisms -- us included.

New research adds to these concerns with evidence that ATP — an energy-storage molecule vital to life on Earth — could survive for months or even years onboard a martian probe.

Andrew Schuerger of the University of Florida and colleagues used a martian simulator to measure the degradation rate of ATP (adenosine triphosphate). This complex organic molecule transports chemical energy through the cells of all terrestrial organisms. It undoubtedly has found its way onto every spacecraft that has ever flown.

"It turned out that under normal equatorial Mars conditions the ATP was a lot more stable than we anticipated," said Schuerger.

If ATP stowaways can survive as long as Schuerger's team observed, they could wind up in life-detection instruments, thereby confounding efforts to detect organic molecules inherent to Mars.

If ATP can survive, why not bacteria? Or viruses? Under the right conditions, in a few thousand years, these could evolve into some form of life we could recognize. But what are the chances of that?

In Schuerger's lab sits the Martian Simulation Chamber (MSC), a half-meter-wide cylinder in which temperature, pressure and radiation levels are controlled to mimic conditions on the Red Planet. Special attention is given to reproducing the ultraviolet light from the sun, which easily penetrates Mars' ozone-less atmosphere and is particularly damaging to biomolecules like DNA.

In previous work, Schuerger and his colleagues placed different bacteria samples in the MSC and found the organisms could not survive more than a few hours in simulated martian sunlight.

"We expect a spacecraft surface will be sterilized on the first day after landing on Mars," Schuerger said.

The short life expectancy of terrestrial microorganisms on Mars is reassuring, but Schuerger and colleagues wondered what would happen to the "dead bodies" and other biological residues that may contaminate the surface of a space probe.

Stilll...what if?

One of the commenters to the article raises an alternate possibility: solar winds carrying off bacteria from the upper atmosphere. If there was some hardy strain that could survive space travel, life could actually be more common than we think it to be.

And...what if...we were the result of an accidental contamination on a probe to the third planet from Sol?

Interesting plot ideas.

1 comment:

  1. I always thought the guys at NASA were the sort who grew up reading sci fi. I guess not. Otherwise they would have thought about contamination long ago.That's often been a theme of the genre.