While NASA has completed about half of the recommendations to be met before returning its space shuttle fleet to flight status, the agency still faces hurdles over the upcoming months, an independent task group overseeing the work said today.

Veteran astronaut Richard Covey, co-chair of the Stafford-Covey Task Group monitoring NASA's return-to-flight efforts, said the agency has met eight requirements from a list of 16 items. They include 15 recommendations by Columbia accident investigators last year and one extra agency goal to develop a safe haven plan for shuttle astronauts to seek refuge at the International Space Station (ISS) during an emergency.

But NASA officials still must develop at least some capability for astronauts to repair their shuttle's tile and reinforced carbon carbon (RCC) thermal protection system in space, task group members said.

"We think that's the long pole in the tent and it's got be worked on harder," said Joseph Cuzzupoli, the task group's technical panel leader, to reporters during a press briefing today at Marshall Space Flight Center in Huntsville, Alabama. "That work is in progress and we're looking forward to the outcome of testing."

Task group members will to monitor NASA tile repair tests on Jan. 7. Last week, space shuttle officials said there some technical challenges came up during tile repair during vacuum tests, when the putty-like substance used to fix tiles to the shuttle's aluminum skin tended to bubble and foam.

"I'm quite comfortable that we will fly with some capability," said retired U.S. Army Col. James Adamson, the task group's operations panel lead, of on-orbit repairs during the briefing. Adamson also said that, even if NASA did not have a certified repair technique or required on-orbit tests, he did not see any reason the shuttle should not fly.

NASA's three-space shuttle fleet has been grounded since the loss of the shuttle Columbia and its crew on Feb. 1, 2003. During the investigations that followed, the Columbia Accident Investigation Board (CAIB) issued 29 recommendations for NASA's shuttle program, 15 of them to be implemented before the next launch.

Shuttle program managers currently plan to launch their first return-to-flight mission, STS-114 Discovery, between May 13 and June 5 of 2005. The flight is expected to test new instruments and methods in-flight orbiter inspection, as well as resupply the ISS.

More time needed

While both NASA officials and task group members expected the space agency to meet all 15 of the CAIB recommendations by the end of this month, task members said the need for additional data prevented the closure of outlying issues.

One CAIB recommendation to provide high-resolution pictures of the shuttle in flight was tabled by the task group until NASA completes work with a 50-foot (15-meter) sensor-laden inspection boom, since it is expected to serve as the primary tool for astronauts to image their spacecraft's undercarriage during future flights.

"We are very demanding in what we ask for in terms of closure." Covey said of signing off on the agency's CAIB recommendation work. "Even though we got [all] closure packages, we still believe we need additional data to be able to make our decisions."

Covey and his fellow task group members remained confident they would be able to complete their assessment of NASA's return-to-flight work as early as March 2005. The group plans to make its final report to NASA at least one month before the next shuttle launches.

"Based on [NASA's] current plans and our activities, we don't see anything that says we can't get our task of assessing done," Covey said.