NASA shuttle managers are expected to
decide later today whether the Atlantis orbiter and its six-astronaut
crew will launch toward the International Space
Station (ISS) on Aug. 27.
A flock of
up to 300 shuttle engineers, managers and contractors are concluding a two-day
Flight Readiness Review for Atlantis' STS-115
mission at NASA's Kennedy Space Center (KSC) in Cape Canaveral, Florida to
decide, among other things, whether four bolts connecting the orbiter's Ku-band
antenna to a forward right payload bay wall will have
to be replaced on the launch pad.
"They'll
come together with a plan and get a decision on what we should do," NASA KSC
spokesperson Bruce Buckingham told SPACE.com Tuesday, adding that a
potential fix is not expected to significantly impact the planned space shot.
Atlantis is
currently set
to launch no earlier than 4:30 p.m. EDT (2030 GMT) from Pad 39B
on an 11-day trip to the ISS. The STS-115 crew, commanded by veteran shuttle flyer
Brent
Jett, will deliver a new
solar array and truss segment to the station in NASA's first major
construction flight since late
2002.
Shuttle fuel
tank also under scrutiny
A standard
meeting before any shuttle flight, this week's Flight Readiness Review also
includes discussions on whether Atlantis' external tank is fit for the nearly
nine-minute trip into orbit. The foam insulation-covered, 15-story fuel tank
carries the same modifications as one which fed the Discovery shuttle's July 4
launch.
Those modifications
- aimed at reducing the amount of foam insulation debris shed at launch - include
the removal of a large, foam-clad wind screen that once covered wiring and
pressurization lines. Like Discovery's fuel tank, Atlantis' does not carry any
changes to a series of 37 so-called ice-frost
ramps, which are NASA's next target for modifications.
"I particularly,
based on what I understand, expect to see no basic change from a debris hazard
standpoint," NASA shuttle program manager Wayne Hale told reporters in a Friday
briefing.
Fuel tank
foam shedding has been a prime concern since the 2003 Columbia accident, when a
chunk of insulation fell during launch and breached the orbiter's heat shield
along its left wing leading edge. The damage led to the loss of the shuttle and
its crew during reentry.
A large
piece of foam also fell from an external tank's protuberance air load (PAL)
ramp during NASA's first post-Columbia shuttle flight in July 2005,
prompting the ramp's removal for Discovery's STS-121
mission last month - a fix that performed
well - and Atlantis' upcoming launch.
With the PAL
ramp gone, ice
frost ramps are now NASA's next target for elimination, but their continued
presence on shuttle fuel tanks prompted two top NASA safety officials to vote
against launching Discovery's STS-121 mission.
"We have a
full court press going on to redesign those," Hale said of the ice frost ramps.
"We're going to be taking them into the wind tunnel in September."
Hale added
that of the top two candidate modifications for fuel tank ice frost ramps, one calls
for a hardy titanium shell to replace ramp insulation, but tests remain to make
sure the potential fix will not form ice when a shuttle tank is filled with its
super-cold liquid oxygen and liquid hydrogen fuel.
The first
shuttle flight to carry an ice frost ramp fix on its external tank is expected
to be NASA's fourth post-Columbia mission, slated to launch between February
and March of 2007, Hale said.
Meanwhile,
NASA will discuss the results of today's STS-115 Flight Readiness Review
meeting during a live NASA
TV broadcast to begin no earlier than 2:00 p.m. EDT (1800 GMT).
You are
invited to follow the briefing via SPACE.com's NASA
TV feed, which is available by clicking
here.
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