LRO Steps Aside For Endeavour
Click here for more news / Clique aqui para mais notícias
By Frank Morring, Jr.
NASA will try again to launch the space shuttle Endeavour on June 17, and still push to get the Lunar Reconnaissance Orbiter (LRO) under way this week as well.
Both spacecraft were scheduled to launch from Florida that day, after a gaseous hydrogen leak forced the shuttle program to scrub Endeavour's planned June 13 launch. But in an effort to "maximize" the space agency's launch opportunities this week, the LRO team relinquished its June 17 slot to the space shuttle program to give Endeavour one more chance to lift off to the International Space Station (ISS) before its launch window closes until July.
Steve Payne, NASA test director, said June 15 that shuttle crews at Kennedy Space Center are on track to repair a hydrogen vent line leak that forced a scrub before the original June 13 launch date. There are even a couple of extra hours to accommodate delays in finishing the work if lightning or other weather forces workers inside.
The leak, very similar to one that forced a scrub on the STS-119 launch in March, came at the point where gaseous hydrogen is vented from the shuttle's external tank into the pad structure at Launch Complex 39A for burnoff. Once it was safe for workers to approach the tank, they found slight gaps where the ground umbilical carrier plate (GUCP) joins the external tank, and set to work to replace the seals.
Payne and Leroy Cain, the mission management team chair, stressed that the root cause of the leak hadn't been discovered. But the same repair protocols that are being followed this time stopped the leak after the STS-119 scrub.
If the repair holds when Endeavour's external tank is filled with supercold liquid hydrogen on the evening of June 16, liftoff of the shuttle will come at 5:40 a.m. EDT the next morning. It will allow Endeavour to accomplish its full planned 16-day mission, including 11 days docked to the ISS.
A shuttle launch the morning of June 17 is expected to give the Eastern Range time to reconfigure for the Atlas V launch with LRO by the afternoon of June 18, with the first of three opportunities that day coming at 5:12 p.m. EDT. The launch timing is important to get the piggyback Lunar Crater Observation and Sensing Satellite (LCROSS) lined up for its planned crash into a polar crater at a time and place that will be visible to Earth-based observatories.
Launch windows also are available on June 19 and June 20 for LRO. After that, the mission will slip until no earlier than June 30. Payne said the shuttle program has agreed to make only one more attempt to launch before its window closes Saturday, June 20, leaving Thursday, Friday and Saturday to get LRO under way. If Endeavour can't launch on Wednesday, the next window would open on July 11.
The STS-127 mission is to deliver the porch-like Exposed Facility for Japan's Kibo laboratory module, as well as three large spare pieces of hardware that won't be deliverable after the shuttle stops flying next year.
The mission also will replace a set of station batteries, install experiments on the Exposed Facility, and return Japanese ISS crew member Koichi Wakata to Earth. U.S. Army Col. Tim Kopra will replace him on the ISS.
Artist's concept of Lunar Reconnaissance Orbiter: NASA
