Astronauts on asteroids? NASA toys with idea

By Leonard David

updated 5:34 p.m. ET July 30, 2007

GOLDEN, Colo. - NASA's Constellation Program — including the deployment of the Orion crew vehicle replacing the space shuttle — will first be assigned to international space station flights, then propel humans and cargo to the Moon. Expeditionary missions to Mars and beyond will follow.

But there's ongoing discussion of mounting a piloted mission to an asteroid — a voyage by astronauts to a near-Earth object. These proponents feel certain of the scientific payoff from reaching, first-hand, an asteroid — perhaps even becoming able to exploit these chunks of celestial flotsam to further humankind's plunge into the cosmos.

Space technologists argue that a NEO trip could be a valuable shakeout of people, equipment, and procedures prior to hurling astronauts beyond the Moon to the distant dunes of Mars.

For others, NEOs are viewed as downright dangerous, in terms of a head-on collision between Earth and a space rock. It's best to get to know these incoming beasts ahead of time.

NASA's NEOphytes
Internal looks by a small group of NASA "NEOphytes" have projected that a human trek to one of those mini-worlds may involve two or three astronauts on a 90 to 120-day spaceflight, including a week or two week stay at the appointed asteroid.

Dispatching astronauts to a NEO is a sensible idea, said Harrison Schmitt, Apollo 17 astronaut, geologist and current chair of the NASA Advisory Council.

In fact, the Exploration and Space Operations subcommittees of the NAC were briefed July 18 by NEO study team members from the NASA Johnson Space Center, although there has been no Council action on the topic.

Schmitt told Space.com: "I think examination of a NEO mission and the development of the stand-by monitoring systems, plans, protocols and procedures for the diversion of a potentially Earth-impacting asteroid would be very prudent activity for the U.S. to undertake."

Additionally, Schmitt said that a NEO mission would be a potentially important demonstration of the versatility and capability of the Constellation systems and a "gap-filler" before any Mars landing mission.

"So far, the arguments for asteroid science and resources are interesting, but not well-developed or potentially as historically or politically persuasive as a demonstration of long-term Earth defense," Schmitt said.

Extended flight
At this point in time, NASA has not issued any formal requirements to augment the Orion spacecraft to handle a piloted NEO mission, explained John Stevens, Director of Business Development for the human spaceflight line of work at Lockheed Martin Space Systems, near Denver, Colorado.

However, the company — builder of the crew-carrying Orion spacecraft – internally funded two years worth of studies to flesh out technologies to support a diversity of destinations, Stevens said. For sojourns to a near-Earth asteroid, he said, future block upgrades to Orion are necessary.

"It's not that difficult from an architecture point of view to fly by an asteroid and then come back," Stevens said. But pulling off a rendezvous and docking with such an object, then rocketing back to Earth, requires more propulsion oomph, he noted, along with the need for larger living quarters for transiting crews, as well as recycling hardware to handle oxygen and water needs.

Also, any roundtrip — Earth-to-NEO-to Earth — is an extended flight, way beyond that required for Moon travel. So that brings up crew psychological-sociological issues. "It's a concern...but we don't know how much of a concern," Stevens advised.

Stevens said that the near-Earth object human mission can be viewed as an intermediate step between a Moon mission and a Mars mission. "In terms of complexity and the length of time that you have to stay out...it does represent a good stepping stone between the kinds of missions you do at the Moon and the kinds of missions that you next bite off...which is the Mars mission," he said.

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