NASA Delays Shuttle Launch Date Decision to April

Work crews sand red dye from the surface of the hail-damaged external fuel tank of NASA's space shuttle Atlantis to help repair thousands of dings gouged into its foam insulation-covered surface. CREDIT: NASA/Jim Grossman.

NASA mission managers will wait until early April to pick a new launch date for the space shuttle Atlantis pending additional repairs and checks of its hail-battered fuel tank, top agency officials said Wednesday.

The U.S. space agency is eyeing April 10 as the decision day on whether to press ahead with a possible mid-May launch for Atlantis or swap its damaged fuel tank with a new one, which would push the planned space shot to June.

"Our ultimate goal is to get the best tank that we can get ready to go fly," William Gerstenmaier, NASA's associate administrator for space operations, told reporters in a Wednesday teleconference. "It looks like by about April 10 or so, we should have enough information."

A new shuttle fuel tank, which would be used if mission managers go for the swap option, is due to arrive at NASA's Kennedy Space Center (KSC) spaceport in Cape Canaveral, Florida on April 10, Gerstenmaier added.

A freak storm bombarded Atlantis at its Pad 39A launch site at KSC on Feb. 26, battering the orbiter and its fuel tank with hail up to the size of golf balls, etching more than 2,500 dings into Atlantis' external tank's vital foam insulation [image]. The resulting damage prompted mission managers to delay the planned March 15 launch of the orbiter's STS-117 spaceflight to allow time for repairs.

NASA currently has a window stretching from late April to around May 21 to launch Atlantis' six-astronaut STS-117 crew towards the International Space Station (ISS). Commanded by veteran shuttle flyer Rick Sturckow, the 11-day mission will deliver new starboard solar arrays to the orbital laboratory.

Swapping out the damaged fuel tank for a new one would push the launch to no earlier than June 8, NASA has said.

NASA shuttle program manager Wayne Hale said Atlantis' hail-spawned delay will likely limit the space agency to launching four orbiter flights this year - as opposed to the ambitious five previously targeted - to continue assembly of the ISS. But that ripple effect will likely dampen out by mid-2008, he added.

"We expect that we will be able to get back on the prescribed [flight] manifest in about 12 months," Hale said of the impact. "It certainly does not affect our plan to complete space station construction by 2010."

NASA plans to complete at least 13 ISS-bound shuttle flights to complete assembly of the $100 billion orbital laboratory by September 2010, when its three-orbiter fleet is due to retire to make way for its successor Orion.

Damage assessment continues

NASA has paid close heed to the health of shuttle fuel tank foam since 2003, when a briefcase-sized chunk popped free during the launch of Columbia and pierced heat shielding on the orbiter's left wing.

The damage led to the orbiter's destruction, and loss of its seven-astronaut crew, during as they reentered the atmosphere, prompting NASA to devise a host of fuel tank improvements to limit foam shedding during liftoff in the future.

But statistically speaking, hail storms the strength of the Feb. 26 tempest are expected to affect a shuttle flight once every 10 years, NASA officials said, adding that the last hail-related damage to shuttle hardware occurred 11 years ago.

NASA's deputy external tank project manager John Honeycutt said Wednesday that most of the damage to Atlantis' tank is concentrated near the nose cone [image], where engineers plan to spray a new layer of foam and then sand it into the proper shape to withstand the aerodynamic heating stresses that occur during launch [image].

"The long pole in the tent here is doing the testing and evaluation to make sure that we can apply this spray foam in a way that it will be safe," Hale said, adding that he is confident the tank can be repaired to fly the STS-117 mission. "We have a high degree of confidence that it will be, or else we wouldn't have picked this route, but that work is still ahead of us."

If everything goes well, and engineering studies of the spray foam repair method and others bear out, Atlantis could be primed to launch in the mid-May timeframe, Hale added.

But shuttle officials stressed that the reason they are not choosing a new launch date for Atlantis now is to allow the agency's engineering teams to complete their tank surveys and repairs without any artificial schedule pressure.

"We're going to fly this tank when it's safe to fly and not before," Hale said.

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