The LIFE menagerie will be packed in individual vials loaded into a titanium disc the width of a credit card. Betts says the packaging has been tested for acceleration forces up to 4,000 g's, or 100 times the expected acceleration during sample return.
Still, some space scientists are scratching their heads why anyone would risk putting Earthly microorganisms anywhere near Mars in the first place, especially given the relatively modest scientific payoff. "Meteorites are millions of years old—a three-year trip is really not relevant," says Daniel Glavin, an astrobiologist at the NASA Goddard Space Flight Center in Greenbelt, Md.
Strange as it may sound, the experiment satisfies international prohibitions against contaminating Mars or other bodies that might support life, says Catharine Conley, NASA's planetary protection officer. Unlike its neighboring planet, airless Phobos is surely sterile, so as long as Roscosmos provides detailed flight information confirming that Phobos Grunt is expected to reach its target moon—a safe distance from Mars—the mission should be in the clear.
"It is an uncomfortable thing," Conley says, "but we have policy. We have good policy."