BEIJING, July 31 (Xinhuanet) -- Proponents may not get their way, but NASA scientists are kicking around the possibility of sending an Orion crew vehicle -- the space shuttle replacement -- on a voyage to an astroid and back as a warmup to a mission to Mars.

    NASA'S Constellation program will first use Orion spaceships for international space station flight, then to take 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 a near-Earth object (NEO) such as an asteroid. Supporters feel certain of the scientific payoff from reaching an asteroid, first-hand.

    Internal looks by a small group of NASA "NEOphytes" have projected 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 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.

    (Agencies)