HOUSTON – NASA officials will track
launch debris with more detail than ever before during the liftoff of the space
shuttle Discovery later this year as the agency pushes to return its orbiter
fleet to flight status.
Using radar
and more than 100 cameras spread across ground stations and high-altitude
aircraft, flight controllers with NASA’s STS-114 mission aboard Discovery
expect to get their clearest view of just how much debris separates from the shuttle’s
external tank in the initial minutes after liftoff.
“We’re
expecting to see more debris than ever before,” said John Muratore, shuttle systems engineering manager, during a
press briefing here at Johnson
Space Center.
That’s
not to say more debris will fall from the orbiter-external tank stack, just
that ground stations will now be able to see more than in the past, he added.
Set to
launch no earlier than May 15, Discovery will be NASA’s first shuttle
mission since the loss of seven astronauts aboard the Columbia orbiter, which broke up during
reentry in 2003 after sustaining critical damage during launch. A chunk of foam
insulation, shaken loose from Columbia’s
external fuel tank, gouged a hole in the orbiter’s left wing leading edge
and allowed hot gases to seep inside the structure on reentry.
While NASA
has since redesigned
external tanks to prevent major chunks of foam – like the suitcase-sized
piece that doomed Columbia
– from striking orbiters. But smaller pieces the size of marshmallows
could rain down on Discovery during liftoff and, depending where they strike,
cause severe damage or remain relatively harmless.
“The
only way to really know what’s going to happen in the real world is to go
fly,” Muratore said, adding that his team ran through more than one billion computer scenarios and conducted live impact
tests to prepare for a safe flight for Discovery. “It’s a very
difficult engineering problem.”
Shuttle
mission managers are planning to conduct a debris verification review meeting
later this week to discuss the debris risk posed to the STS-114 mission, NASA
officials said.
Radar
installations placed north and south of Discovery’s launch pad, and an
additional ship-board platform that will observe the shuttle as it passes over
the Atlantic Ocean, were successfully tested
last year during NASA’s launch of the Mercury probe MESSENGER.
Meanwhile, engineers are outfitting two WB-57 aircraft
with turret-mounted cameras that will track Discovery’s launch from an
altitude of 60,000 feet.
“I
have a really high level of confidence that if we have any damage on the
vehicle, we’re going to be able to detect it,” said John Shannon, shuttle
flight operations manager, of the new imaging and radar systems. “I have
zero doubt..nothing is going
to get by us. The question is what to do about it then.”
NASA has
spent the last two years trying to develop a set of repair techniques for
astronauts to employ in orbit should their shuttle suffer damage to its thermal
protection system of tiles and reinforced carbon carbon
(RCC) panels. Discovery will carry materials for some of the five methods
currently on the table. During the spaceflight, STS-114 mission specialists
Stephen Robinson and Soichi Noguchi will test two
repair techniques, including an emittance wash
application for tiles and a caulk-like substance to fill in cracks in RCC
panels.
Discovery
mission planners are currently hoping to roll the orbiter, currently attached
to its external tank-solid rocket booster combo, out to its launch pad this
week.
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