NASA Defers Launch Pad Decision

Senior NASA managers won't decide until March whether to release one of the two space shuttle launch pads at Kennedy Space Center (KSC) for the first flight test of the follow-on Ares I crew launch vehicle.

As the U.S. space agency moves into the tricky transition from retiring the shuttle to the beginning of development tests for the Ares I, scheduling activities at the KSC pads is critical. At a Johnson Space Center (JSC) meeting Jan. 22, top spaceflight managers decided there was no immediate need to decide whether they will need both of the pads for the upcoming mission to the Hubble Space Telescope.

Meeting with their human-spaceflight counterparts at JSC, Hubble managers and engineers said they believe they will have a replacement computer ready to go to the telescope in time to meet the scheduled May 12 launch date for the final shuttle servicing mission to the telescope.

The computer, which will replace a unit on the orbiting observatory that failed shortly before the original launch date of the STS-125 Hubble servicing mission last year, is being certified at Goddard Space Flight Center. NASA postponed the servicing mission because engineers didn't want to service and upgrade it and then leave it in orbit without redundant data-handling computers.

Meanwhile, crews are stacking the Ares I-X flight vehicle - a mostly boilerplate flight article designed to test both flight dynamics and ground infrastructure. They are making as many modifications to Launch Complex 39B as possible to ready it for the new vehicle, without precluding a shuttle launch in case one is needed to rescue the STS-125 crew. But they need to get total access to the pad to finish the work in time for the planned July Ares I-X launch date.

By mid-March it should be clear if the pad and flight hardware will be far enough along to support a July launch. Meanwhile, the shuttle program will continue to study whether it will be possible to launch both the Hubble-servicing mission and, if necessary, a rescue mission from the other KSC pad, Launch Complex 39A.

If the Ares I-X project is ready to proceed in mid-March, spaceflight managers will decide then whether to free Pad B to support the July date by holding the rescue shuttle in the Vehicle Assembly Building for what is called "launch on need." John Shannon, the shuttle program manager, has said there would be "significant technical issues with that approach."

If those difficulties are deemed insurmountable, the shuttle program will retain control of Pad B until after the Hubble mission is launched and cleared for landing. That would force a delay of the Ares I-X test, probably into the fall.

The pad-release discussion assumes that STS-119 - the next space station assembly flight - will get off as planned on Feb. 12 and return to KSC about two weeks later.

Atlantis shuttle photo: NASA

AVIATION WEEK Copyright 2009, The McGraw-Hill Companies, Inc. All Rights Reserved.