NASA is close
to meeting all of the return-to-flight safety requirements set by
Columbia accident investigators and should be able to launch a shuttle by May
2005, shuttle program officials said today.
"I am confident we can
launch in the May to June timeframe," said Bill Parsons, space shuttle
program manager, during a briefing with reporters. "We're really looking
forward to that...I think everyone is ready for that
launch."
Also today, NASA released
the latest report on its return-to-flight progress, a 268-page document that
states the agency has addressed the 10 remaining issues laid out by the
Columbia Accident Investigation board (CAIB) last year. The work will be
forwarded to an independent task group for review.
That task group, led by
veteran astronauts Thomas Stafford and Richard Covey, is expected
to evaluate NASA's latest return-to-flight progress in upcoming weeks and
hold a public meeting on Dec. 16. NASA already addressed five other CAIB
recommendations earlier this year.
"We have a good plan, an
excellent plan, in place," said John Casper, NASA manger of space shuttle
management integration and planning, of NASA's return-to-flight during the
briefing.
NASA's three remaining
space shuttles have been grounded since Feb. 1, 2003, when the shuttle
Columbia broke up over Texas during reentry killing its seven-astronaut
crew.
Shuttle program officials
are currently targeting a daytime launch window between May 12 and June 3 for
the next mission, STS-114 aboard the shuttle Discovery. The flight is
expected to test new hardware and procedures for in-flight orbiter inspection,
as well as rendezvous with the International Space Station (ISS) to deliver
fresh supplies and equipment.
Still more work
needed
Some aspects of NASA's
shuttle program still need more work, such as plans to develop
in-orbit techniques to repair heat-resistant tiles and the reinforced
carbon carbon (RCC) panels along wing leading edges that protect shuttles from
the searing heat of reentry.
"Right at this moment we're
still working on the technical details on how to do tile and RCC repair,"
Parsons said, adding that additional thermal protection system tests are set for
this week. "We think there are some issues to be
resolved."
Tests with tile repair
methods found that the putty-like substance astronauts would use to attach
replacement tiles to the shuttle tends to bubble and foam in vacuum, which could
leave unwanted voids between the tile and spacecraft skin.
But having a proven method
of to repair RCC panel repair is not a set requirement for the first
return-to-flight mission, and Parsons
said that the Discovery crew will have at least some processes to
draw on should it become necessary. In-flight tile repair tests in the
shuttle's payload bay are also planned for the mission, he
added.
"Our goal is to have the
maximum amount of repair capability," said Wayne Hale, deputy space shuttle
program manager. "It is going to be a continually evolving
thing."
Returning to
flight
Among the features of the
upcoming flight is a new foamless bipod fitting that connects
Discovery to its external tank. During Columbia's launch, insulating foam
from its own bipod fitting broke off and damaged the shuttle's left wing,
allowing hot gases to enter the wing during reentry and destroy the
spacecraft.
Discovery's next flight
will also mark the first flight of a sensor system to measure temperature
and impacts on wing leading edges, as well as an orbital boom to
allow astronauts to examine the shuttle's undercarriage in Earth orbit.
"It's not just a stick,"
Hale said of the 50-foot boom, adding that it will sweep the ship with two
tip-mounted sensors to look for problem areas.
Meanwhile, engineers at
NASA's Kennedy Space Center in Cape Canaveral, Florida have begun assembling the
twin solid rocket boosters that will launch Discovery into space. The shuttle's
main engines are also expected to be attached to the orbiter soon and the
mission's external tank, which holds the critical fuel for the mission's ascent,
is expected to be shipped to KSC around Dec. 31.
"We're looking forward to
return to flight," Parsons added. "We think we've turned a
corner."
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