Solid rocket booster tests could be ordered
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 26, 2006; Updated at 2 a.m. Aug. 27 following MMT meeting
NASA's Mission Management Team decided early Sunday to continue testing and analysis to assess the possible effects of a launch pad lightning strike Friday on the shuttle Atlantis' solid-fuel booster and self-destruct systems. A Monday launch attempt remains feasible for now, sources said, but only if the community agrees time-consuming tests to verify the health of booster and range safety pyrotechnic systems are not needed. If the tests are required, launch likely would slip to mid week or later.
The Mission Management Team plans to meet again at 6 p.m. Sunday to discuss the progress of the analysis and to make a decision on how to proceed.
The lightning bolt hit Friday, pumping some 100,000 amps of current through the launch pad's lightning protection system. Lightning strikes typically generate 5,000 to 20,000 amps of current and the bolt Friday is one of the strongest on record at the Kennedy Space Center.
Telemetry showed a very small "spike" in one of the shuttle's electrical buses and a larger surge in the circuity associated with a launch pad pyrotechnic device used to disconnect a hydrogen vent arm from the shuttle's external tank.
Concern that induced currents could have affected other sensitive electrical systems on the pad or in the shuttle, Mission Management Team Chairman LeRoy Cain on Saturday ordered Atlantis' launch delayed for at least 24 hours, from Sunday to Monday at 4:04 p.m., to give engineers a chance to assess their systems.
Later Saturday, representatives of the shuttle booster program and the range safety system raised concerns that prompted a late night meeting of the Mission Management Team.
Atlantis was powered up when the lightning struck and an analysis of the powered systems shows no problems. But the boosters were not powered and engineers have no data to assess the health of critical components. At issue is whether the strike might have affected circuity that fires explosive charges used during booster ignition and separation. Similar concerns were raised by Air Force range safety officers about the shuttle's self-destruct system.
To test those circuits and their pyrotechnic initiator controllers, or PICs, engineers would first have to drain liquid oxygen and hydrogen from the shuttle's fuel cell system and open the ship's aft compartment. Ordnance would have to be disconnected and then reconnected as part of the verification process. Then engineers would have to close out the aft and reload the shuttle's fuel cell supplies to ready the ship for launch.
If such tests are ordered, sources said early today, launch likely would be delayed to late this week.
But it may be possible to clear the PIC systems without disconnecting the ordnance based on more detailed analysis of shuttle grounding and response to electrical transients. If that turns out to be the case, NASA could, in theory, press ahead with launching Atlantis Monday.
But as of this writing, it is not clear when a decision to pick up the countdown would have to be made. Updates will be posted as warranted.
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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