New Shuttle Launch Seen 5:40 A.M. ET Wednesday, Launch Of Double Robotic Lunar Craft Delayed To Thursday At Earliest; Later Windows Examined
Grueling 16-Day Mission To Station At Issue; Any Further Problems Might Mean Endeavour Liftoff Could Be On Weekend: NASA Leaders
Space Shuttle Endeavour still sits on the ground thanks to a leaky gaseous hydrogen venting system, meaning liftoff on the STS-127 Mission to the International Space Station is delayed at least four days, with launch now set for 5:35 to 5:40 a.m. ET Wednesday.
The latter time is preferred.
And, if a swap-out of seals on a ground umbilical carrier plate on the External Fuel Tank (EFT) hydrogen venting line doesn’t cure the problem, a further launch delay to Saturday might be possible. But briefers said this afternoon that they expect to be able to get the work done before the new launch time Wednesday, though they might have to use an hour or two of extra slack in the window.
If Endeavour problems further persist, liftoff might be delayed into next month, which might not be good, because July launches aren’t optimal, They involve launching in the evening, and Florida weather in July can disrupt launch plans.
Other than the hydrogen venting system leak, the shuttle itself is in good shape, with all systems nominal, ready for launch.
This problem, or something very much like it, has occurred previously, and not long ago. A hydrogen leak on the same sort of line was seen on the external fuel tank with Space Shuttle Discovery on the STS-119 Mission in March. (Please see Space & Missile Defense Report, Monday, March 16, 2009.) The same repair process is being used this time on Endeavour, with the same tight race to make the fix.
The vent line runs from the carrier plate, away from the launch pad to a flare stack where excess hydrogen is burned off safely. It is unclear at this point whether the umbilical carrier plate will be redesigned to prevent the problem from recurring yet again.
NASA leaders outlined why this delay to fix the leak is far more complicated than it sounds, speaking in a news conference last night and another media briefing this afternoon.
First, most inconveniently, Endeavour is attempting to get off the ground at Launch Pad 39A at Kennedy Space Center, Fla., just about the same time that another NASA mission, an unmanned trip to the moon, is attempting to launch from a nearby pad at Cape Canaveral Air Force Base, Fla.
That mission, featuring the Lunar Reconaissance Orbiter and the Lunar Crater Observation and Sensing Satellite (LRO and LCROSS) has been scheduled to lift off Wednesday. But obviously, NASA can’t launch Endeavour and LRO-LCROSS on the same day down the same Eastern Range.
The plan, therefore, is to give priority to Endeavour, and let it launch Wednesday, with LRO-LCROSS departure deferred to Thursday or later, Cain and Pete Nickolenko, shuttle launch official, said.
For the lunar craft, there are three launch opportunities from Canaveral Thursday at 5:12 p.m., 5:22 p.m. or 5:32 p.m.
If that liftoff of LRO and LCROSS is postponed 24 hours, launch times Friday are 6:41 p.m., 6:51 p.m. and 7:01 p.m. Saturday opportunities are 8:08 p.m., 8:18 p.m. and 8:28 p.m.
Shuttles Must Retire
Second, another complication is that the clock is ticking toward a deadline of Sept. 30, 2010, when then-President Bush decreed the space shuttle fleet must stop flying, so as to free up money to develop the next-generation U.S. spacecraft replacing the shuttles, Orion-Ares.
“Each delay in shuttle launches moves us closer [to the point where] I can no longer finish” all the shuttle missions on the current manifest by the deadline next year, said LeRoy Cain, NASA space shuttle launch integration manager.
Eyeing the latest delay for the Endeavour launch, he said, “This would be additive to that” crunch in the timeline. “Sooner is better,” he said.
Another reason that Endeavour would be given precedence in taking the Wednesday launch slot is that this approach provides the maximum number of potential opportunities for both the STS-127 shuttle mission and the LRO-LCROSS mission, Cain said.
“It looks like the shuttle [launching] on the 17th maximizes our opportunities,” he said. But he acknowledged that for the launch to come off well, “a lot of things have to go our way.”
The STS-127 Mission
The marathon 16-day Endeavour mission is supposed to involve five spacewalks and complete construction of the Japan Aerospace Exploration Agency’s Kibo laboratory. Astronauts will attach a platform to the outside of the Japanese module that will allow experiments to be exposed to space. It is nicknamed the space station front porch.
Things are getting so difficult in scheduling the STS-127 Mission that NASA officials are having to consider launch times and mission periods that might not be optimal. One possibility would force the space agency to make the final spacewalk a contingency maneuver, Cain said.
The STS-127 crew members are Commander Mark Polansky, Pilot Doug Hurley and Mission Specialists Dave Wolf, Christopher Cassidy, Tom Marshburn, Tim Kopra and Canadian Space Agency astronaut Julie Payette. Kopra will join the space station crew and replace Japanese astronaut Koichi Wakata. Wakata will return to Earth on Endeavour to conclude a three- month stay at the station.
Polansky, who has a Twitter account named Astro_127, can be followed online at: http://www.twitter.com/Astro_127 for those wishing to track his activities, NASA announced.
LRO-LCROSS
Those moon missions involve intentional crash landings on lunar terrain, with a goal of discovering whether there is water on the moon that could sustain U.S. astronauts during extended missions there.
LRO is scheduled for a one-year exploration mission at a polar orbit of about 31 miles, or 50 kilometers, the closest any spacecraft has orbited the moon. The primary objective of LRO is to conduct investigations to prepare for future explorations of the moon.
Launching with LRO is LCROSS, a partner mission that will search for frozen water on the moon by sending the spent upper-stage Centaur rocket, about the size of a sport utility vehicle, to impact part of a polar crater in permanent shadows.
LCROSS then will fly into the plume of dust left by the impact and measure the properties before also colliding with the lunar surface.
That LCROSS impact with the moon will be watched closely from observatories on Earth.