Sean O'Keefe, administrator of the National Aeronautics and Space Administration disclosed that the agency is considering plans to accelerate work on the space plane, NASA's most ambitious effort in decades. The space plane would carry astronauts, but not heavy equipment, to the International Space Station.
Last week, two leading members of the House Science Committee urged NASA to defer development of the spacecraft because of concerns about cost and its potential benefit.
The lawmakers, Reps. Sherwood Boehlert, a Republican and Ralph Hall, a Democrat, warned O'Keefe in a letter it was "too soon to know whether (the space plane) will significantly increase crew safety for missions to low-Earth orbit, and we believe that any crewed replacement vehicle will be judged by the extent to which it significantly improves safety."
But during a hearing Wednesday, O'Keefe outlined the importance of carrying astronauts into such low orbits as pivotal to driving America's longer-term space objectives.
O'Keefe said NASA needs a better understanding of why astronauts quickly lose muscle and bone mass in outer space and must further study questions over generating power and propulsion in space.
"I guess we better get on the matter of developing a space plane," said Sen. Bill Nelson. "It looks like the House of Representatives is beginning to give you some heartburn."
O'Keefe responded: "I keep Rolaids handy all the time, as well as Advil," naming medicines for stomach ailments and headaches. He acknowledged that the concerns expressed last week by Boehlert and Hall were legitimate, but told Nelson, "We are exploring the option to accelerate" development of the space plane.
Ret. Navy Adm. Harold Gehman Jr., who led the investigation into the Columbia disaster, offered support for O'Keefe, arguing the importance of overcoming the technical challenges to sending astronauts into orbit and safely returning.
"We have to do it," Gehman said. "We do really need to perfect getting into and out of low-earth orbit," which, he added, "isn't very jazzy."
Both Gehman and O'Keefe were expected later Wednesday to testify before the House Science Committee.