Discovery Launch May Slip to Dec. 3

Houston—With repairs to the fuel tank of the shuttle Discovery still underway, NASA shuttle program managers on Nov. 18 retargeted the earliest date for a second round of launch opportunities for the agency’s senior orbiter from Nov. 30 to Dec. 3. The delay will permit more time for agency managers to establish flight rationale using the repaired fuel tank. The upcoming launch period will close three days later to permit a Dec. 15 Soyuz launching with three U.S., Russian and European space station crewmembers. Other station activities and shuttle thermal control system restrictions are steering the opening of the next launch period toward late February. Meanwhile, technicians at NASA’s Kennedy Space Center applied doublers to a pair of cracked external fuel tank stringers Nov. 18, following a successful high-pressure check of a replacement for the leaky Ground Umbilical Carrier Plate that played a role in Discovery’s launch scrub earlier this month. Equipment Storage Module A substantial hydrogen leak at the GUCP prompted mission managers to call off a Nov. 5 attempt to launch Discovery on an 11-day flight to equip the station with an equipment storage module and an external spare parts platform. The Nov. 17-18 leak checks were carried out using helium at ambient and higher than ambient pressures. No leaks were detected. Bill Gerstenmaier, NASA’s associate administrator for space operations, will lead a senior management level reassessment of Discovery’s readiness from Johnson Space Center, Texas, on Nov. 29, a week later than previously announced. The delay permits shuttle managers more time to develop a set of flight rationale, which will be presented at a special Nov. 24 shuttle program requirements control board meeting. Hydrogen Leak If an agreement on flight rationale is reached, the Nov. 29 session will include a “go/no-go” decision on whether to proceed during the abbreviated December launch period. The review will include a discussion of the repairs and causes of the hydrogen leak, the stringer cracks, and a 20-in. separation of the external tank insulating foam overlaying the stringer damage. “They are not trying to drive this to a particular launch date,” said NASA shuttle program spokesman Mike Curie on Nov. 18. “If they believe the work can be done when the window opens, that is when we would be prepared to launch. But if the work takes longer, then we will wait. We won’t fly until we are ready.” Alpha Magnetic Spectrometer Endeavour is tentatively set for a Feb. 27 liftoff on the final scheduled shuttle mission, a flight to equip the station with the $2 billion Alpha Magnetic Spectrometer. However, NASA is reassessing the schedule of near-term station activities in case Discovery’s readiness falls beyond Dec. 6, Curie said. On Nov. 18, technicians placed 13-in. structural doublers on two adjacent 21-ft.-long lithium alloy stringers. In all, 108 stringer support structures surround the upper region of the fuel tank that separates internal hydrogen and oxygen propellant containers. Similar cracks have been repaired at NASA’s Michoud Assembly Facility, La., external tank production plant but not at the launch pad. New insulating foam will be sprayed over the new doublers.