MOUNTAIN VIEW, Calif. — The search for signs of life on Mars may have just gotten a lot cheaper.

NASA is working with private spaceflight firm Space Exploration Technologies (SpaceX) to plan a mission that would search for evidence of life buried in the Martian dirt. The NASA science hardware would fly to the Red Planet aboard SpaceX's Dragon capsule, which the company is developing to ferry cargo and astronauts to and from the International Space Station.

This so-called "Red Dragon" mission, which could be ready to launch by 2018, would carry a cost of about $400 million or less, researchers said.

"I just want a cheap delivery system to go to Mars," said astrobiologist Chris McKay, of NASA's Ames Research Center here. "I don't care how it gets there." [The Falcon and Dragons of SpaceX]

Mission to Mars

The mission doesn't have an official name, McKay said. "Red Dragon" is just what he has been calling it informally.

McKay and his colleagues are developing the Red Dragon concept as a potential NASA Discovery mission, a category that stresses exploration on the relative cheap. NASA is currently vetting three Discovery candidates, one of which it will choose for a 2016 launch. That mission will be cost-capped at $425 million, not including the launch vehicle.

Red Dragon is not in that group of three finalists. NASA will make another call for Discovery proposals in 18 months or so, McKay said, and he and his team plan to be ready for that one. If Red Dragon is selected in that round, it could launch toward Mars in 2018.

Assuming that $425 million cap is still in place, Red Dragon could come in significantly under the bar.

"We'd have money left over to do some science," McKay told here Saturday (July 30) during the NewSpace 2011 conference, which was held at NASA Ames. "Wouldn't that be great?"

Drilling into the ice

Red Dragon wouldn't be the next Mars surface mission.

NASA is currently gearing up to send a car-size rover called Curiosity to Mars as the centerpiece of the agency's $2.5 billion Mars Science Laboratory (MSL) mission. MSL is slated to launch this November and arrive at the Red Planet in August 2012.

Curiosity will use a suite of 10 sophisticated instruments to assess whether Mars is, or ever was, capable of supporting life. Red Dragon, on the other hand, would actually look for evidence of that life. [5 Bold Claims of Alien Life]

"We'd try to detect molecules that are proof of life, like DNA or perchlorate reductase," McKay said. "That's what we'd be searching for — proof of life through biomolecules."

The Martian surface today is bone-dry and bombarded by damaging ultraviolet radiation, making life unlikely to survive there. But Red Dragon would drill 3.3 feet (1 meter) or so underground, in an effort to sample reservoirs of water ice known to lurk under the red dirt.

Researchers are looking at two possible Martian sites for Red Dragon's mission, McKay said. One is the landing site of NASA's Phoenix lander; the other is where NASA's Viking 2 lander touched down in 1976. Both areas are known to harbor subsurface ice. [Infographic: Mars Landers and Rovers Since 1971]