Colorado Springs - Brewster Shaw, the former space shuttle  commander who heads Boeing's human spaceflight business, raised an interesting  possibility at the 24th National Space Symposium here this morning.

For "a couple of billion dollars more," Shaw says, NASA could keep flying a single space shuttle through the anticipated gap in U.S. human access to space between the now-scheduled retirement of the shuttle fleet in 2010 and the beginning of operations with the follow-on Ares I/Orion stack in 2015.

Basically, the idea would be to keep enough infrastructure set up for operating a single shuttle - one bay of the Vehicle Assembly Building, one mobile crawler, one pad, etc. - to accommodate one shuttle, and use the other two orbiters as hangar queens to supply parts no longer available from a dwindling shuttle-supplier base.

Shaw stressed that  the only way it would work would  be if the extra billions were "new money" unrelated to NASA's already-overfilled plate of programs. The idea has been pushed on Capitol Hill by members of Congress facing major job  losses among their constituents when the shuttle stands down.

"We've looked at  it enough that something like that is feasible, but it would have to be something that NASA wanted to have happen, because they would have to enable it," he said. "We can't keep the  option open. NASA has to keep the option open."

NASA isn't about to do that under present circumstances, given the push to keep the gap as short as possible by flying Ares/Orion as quickly as possible. But in addition to preserving shuttle jobs at Kennedy Space Center and elsewhere, the advantages  to continuing to  fly space shuttles to the International Space Station are obvious. As shuttle commander Eileen Collins put it, "one of the biggest losses  is the  cargo-carrying capability."

Even with the new European Automated Transfer Vehicle in the mix, nothing on the drawing board can carry cargo to the space station like the shuttle, and nothing can bring it back to Earth.  The final few shuttle flights are scheduled to carry as many of  the largest spare parts as possible to the station to keep it going after the shuttle retires.

But NASA has its own use for a couple of billion dollars. With that amount the agency says it would have the  same level of confidence that Ares/Orion actually will fly in 2013 that is has it can accomplish the feat in 2015. Engineers from NASA and its contractors, incuding  Boeing, already are working toward the earlier date internally, and the extra funds would be a hedge against the technical problems that are inevitable in any engineering  effort of this scope and complexity. Continuing to fly the shuttle might be a nice--to-have for Boeing, in its role as shuttle contractor, but the company sees its interest with the newer systems.

"If the government decides that that's the best course of action, for all of the reasons that we all talk about, then we would be willing to support that, as long as it doesn't damage the future of America's space exploration effort," Shaw said of continuing to fly the space shuttle.