Lightning delays Atlantis launch a day
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 26, 2006
The lightning bolt that hit launch pad 39B Friday was one of the most powerful on record at the Kennedy Space Center, sending some 100,000 amps of current through the lightning protection system, officials said today. While the lightning protection system worked, shielding the shuttle Atlantis from a direct hit, engineers are concerned about induced currents that showed up in a brief spike in one of the shuttle's main circuits and another in a launch pad pyrotechnic system.
At the same time, telemetry indicated a spike in the circuitry associated with a pyrotechnic device that releases a hydrogen vent arm from the side of the shuttle's external tank at liftoff. Engineers inspecting the pad later reported a burning smell in the area of the gaseous hydrogen vent arm, but no obvious signs of damage were seen.
LeRoy Cain, chairman of NASA's Mission Management Team and director of shuttle integration at the Kennedy Space Center, delayed Atlantis' launch for at least 24 hours, from Sunday to Monday at 4:04:18 p.m., to give engineers time to inspect the vent arm system and to carry out additional tests and analyses. The forecast Monday and Tuesday is 80 percent "go."
The MMT will meet again at 10 a.m. Sunday to hear an update from the engineering community and to make a decision about whether to proceed to launch Monday or order an additional delay. As of this writing, it's not at all clear how that discussion might go.
Video of the lightning strike at pad 39B showed a large bolt hitting the mast atop the shuttle gantry that anchors the pad's lightning protection system. The shuttle wasn't hit and other than the slight 20-millisecond spike in the shuttle electrical bus, and the concern about the hydrogen pyrotechnic device, there are no other known problems.
"I did press pretty hard to see if it made sense in any way, shape or form to reconvene the team later today to attempt to see if we might be able to still have a viable launch opportunity tomorrow," Cain said. "And based on everything I heard, it was pretty clear to me that we need to let the folks go off and look at their data. So that's what we're going to do.
"We have a launch period here that allows us to go do that. We need to make sure we have a good ground and flight system. So the mission management team will reconvene tomorrow morning at 10 a.m. and we'll see where we are."
The goal of the 116th shuttle mission is to deliver a $372 million solar array truss segment to the international space station, a complex assembly task requiring three spacewalks to complete.
The shuttle's launch window, based on a requirement to launch in daylight and to avoid conflict with a Russian Soyuz launch, runs through Sept. 7. Atlantis' fuel cell system has enough on-board liquid oxygen and hydrogen for launch attempts Monday, Tuesday and Wednesday, although NASA does not usually make three attempts in a row.
After that, NASA managers would have to discuss a variety of options based on when the shuttle's fuel cell supplies would need to be topped off to preserve the option of extending the mission in orbit if necessary. Before today's scrub, NASA's launch strategy called for seven launch tries between Sunday and Sept. 7.
The official crew patch for the STS-115 mission of space shuttle Atlantis to resume orbital construction of the International Space Station.
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