All Systems Go

[I think not]

NASA counts down to 4th of July launch
Weather outlook improves; latest tank-foam issue resolved

CAPE CANAVERAL, Fla. - For the third time, NASA loaded the shuttle Discovery's external tank with rocket fuel — this time in preparation for what could be the space agency's first Fourth of July shuttle launch.

Forecasters provided the best weather outlook yet for Tuesday's scheduled 2:38 p.m. ET liftoff: an 80 percent chance of acceptable conditions for launch, with the main concerns having to do with potential rain showers or thunderstorms near NASA's Kennedy Space Center. Threatening clouds forced NASA to call off the first two launch attempts, on Saturday and Sunday.

Discovery's 12-day mission is aimed at testing safety modifications made since the shuttle's last flight, almost a year ago — including a redesign of the shuttle's external fuel tank to remove a troublesome patch of foam insulation. The shuttle also will resupply the international space station, install new equipment on the station and leave behind German astronaut Thomas Reiter as the station's third crew member.

Although NASA didn't plan it this way, the Fourth of July launch would be a symbolic plus. On a day traditionally given over to fireworks displays, the space agency is planning on a safe and sane ascent powered by almost 4 million pounds (1.8 million kilograms) of rocket fuel, including 1.6 million pounds in the tank and almost 2.4 million pounds in the solid rocket boosters.

"What a great gift NASA could give the nation if we returned the shuttle to operation on Independence Day," John Shannon, chairman of Discovery's management team, said on Sunday. "We're really looking forward to that, and if the weather is good, that's exactly what we'll do."

Another foam question
For this third launch attempt, the big question had to do not so much with the weather but with a familiar technical issue: the tank-foam insulation. After Sunday's launch was scrubbed, pad inspectors noticed that the foam insulation around a bracket on Discovery's external fuel tank was cracked. Later, they found that a 3-inch-wide (7.5-centimeter-wide) piece from that cracked area had fallen off.

NASA managers concluded that the crack was created because rainwater entered a tiny crevice in the bracket foam during Sunday's aborted countdown, then froze and widened the crack. When the ice thawed, that weakened the foam enough to cause the break-off.

The foam fragment — which weighed about as much as a penny and looked like a corner of bread crust — sparked additional rounds of inspections and multiple meetings of Discovery's mission management team.

Tank-foam debris has been a concern since the Columbia tragedy in 2003, when a piece of flying foam damaged the wing's leading and eventually led to the loss of the shuttle and its crew. It took two and a half years to redesign the tank and introduce other safety improvements — but foam was once again seen breaking off from the tank when Discovery ascended to orbit last year.

As a result, NASA did another tank redesign — and some engineers within the space agency have said publicly that Discovery's launch should have been held up for still more modifications. Thus, any foam loss, however slight, causes concern.

Managers give go-ahead
Discovery's mission management team mulled over the foam-loss concern during meetings on Monday, and signed off on three issues to clear the tank for launch:

• Engineers determined that the foam loss didn't pose any aerodynamic concerns.
• Projections indicated that the gap in the foam would not lead to excessive ice buildup on the tank, but inspectors were keeping a close watch on that area. If a problem was spotted, the countdown would be stopped, managers said.
• Workers improvised a new inspection device, consisting of a camera mounted on the end of an 8-foot-long (2.4-meter-long) flexible plastic tube, to determine that there were no new areas of concern on the fuel tank.

Some observers wondered whether NASA was moving too resolutely toward launch, a phenomenon known as "go fever." Mission managers already have modified their flight rules once by determining that Discovery's crew could work around a bad heater for a maneuvering thruster rather than waiting for a fix.

"If those guys aren't more nervous than I am, they've become jaded and should resign their positions," physicist Doug Osheroff, who served on the Columbia Accident Investigation Board, told The Associated Press.

However, Gerstenmaier said the space agency was setting objective criteria for liftoff, and consistently following those criteria. "I don't think we're taking any additional risk than we did in our original assessment," he said.

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[I think not]

'Good luck and God speed'

KENNEDY SPACE CENTER, Florida (CNN) -- The space shuttle Discovery and its seven-member crew roared into space Tuesday afternoon -- NASA's first manned launch on Independence Day and its second shuttle flight since the Columbia accident of 2003.

Plans call for a 12-day mission to deliver supplies to the international space station and drop off European Space Agency astronaut Thomas Reiter, of Germany, who will join the Expedition 13 crew members already there.

Astronauts Piers Sellers and Mike Fossum will conduct two spacewalks to test a new shuttle robotic arm and to repair a piece of equipment outside the space station.

They might also do a third spacewalk to test repair techniques on the shuttle's thermal protection system.

NASA decided to go ahead with the launch after finding a pencil-sized crack in the foam insulation around the shuttle's fuel tank on Monday.

"It all looks fine, and the structure is in good shape," Associate Administrator William Gerstenmaier told reporters Monday evening.

The astronauts were all smiles as they suited up Tuesday morning.

Cmdr. Steve Lindsey appeared relaxed, shaking a crew assistant's hand before entering the cockpit where he was strapped into his seat for the ride into space.

Mission Specialist Lisa Nowak was the last to take her seat, and the hatch was sealed at 12:29 p.m. ET.

"They were feeling great, they feel ready to go," said astronaut Scott Kelly, whose brother Mark Kelly is the pilot of the shuttle.

NASA had delayed the launch Saturday and Sunday because of bad weather.

Tuesday's conditions gave NASA its best opportunity for launch. Crosswinds at the shuttle landing facility were "brisk" but within the limit for a safe return-to-launch-site abort landing, according to NASA mission control and its weather team.

Earlier Tuesday, in the course of the latest inspections, a circuit breaker in the shuttle's backup heating system was found to be not working, NASA officials said.

However, the agency decided not to send a team to switch it out, because the main system is functioning and officials feel comfortable flying as-is.

Narrow crack
The launch was threatened a third time Monday after an inspection found a 4- to 5-inch crack in the external fuel tank's foam insulation.

The cracked insulation covered a bracket that connects the liquid oxygen feed line to shuttle Discovery's external fuel tank.

Engineers believe the problem stemmed from a buildup of frozen condensation that crushed a small piece of foam, Deputy Program Manager John Shannon told reporters earlier Monday. The crack was discovered during an inspection Sunday evening, NASA said.

When engineers went to inspect it, they found a .0057-pound, 3-inch piece of foam had "pinched off."

Even so, Shannon said, had that piece fallen off during launch, it wouldn't have damaged the orbiter.

"It turns out there is more foam on this strut than is really needed for its intended purposes," Gerstenmaier said.

Investigators blamed a 1.6-pound piece of foam insulation falling from the external fuel tank for the damage that caused the loss of Discovery's sister ship Columbia. All seven astronauts aboard the shuttle died when it broke up on re-entry over Texas in February 2003.

NASA spent nearly 2 1/2 years redesigning the tank, but during Discovery's mission last year a 1-pound piece of foam broke loose from the external tank, just missing the orbiter.

"I think it would not have gotten as much attention prior to Columbia as it is getting now," Shannon said. "I think it's a very good thing that we have this sensitivity and that we're looking this closely at the vehicle."

Safety concerns
NASA's decision to resume shuttle flights this summer is not without controversy.

In the weeks leading up to the launch, two NASA officials, chief engineer Chris Scolese and chief safety officer Bryan O'Connor, gave a "no go" for the launch.

Program manager Wayne Hale said NASA engineers have learned a lot about foam dynamics in the past year, but there is no way to stop the foam from flying off the tank.

NASA Administrator Michael Griffin called the disagreements with the repairs a good sign that the culture at NASA has changed. The agency was faulted by the Columbia investigation board for having a conformity of opinion.

"I personally want every engineer to express the best opinion that they can give us," Griffin said.

He and top senior officials took into consideration O'Connor's and Scolese's concerns but concluded that if falling foam damages Discovery, engineers will know about it, and the crew can take refuge on the space station and wait for a rescue mission.

Griffin said he wants to fly now because the shuttle program is slated to end in 2010, and NASA is committed to flying at least 16 missions to complete the space station. He said he worries that delays now will lead to dangerous schedule pressure later.