CAPE CANAVERAL, Fla. - For the second time in two weeks, the seven-astronaut crew of the space shuttle Discovery flew into NASA's Florida spaceport Friday as they prepare for a July 26 launch.
"This would be a great day for a launch," veteran astronaut Eileen Collins, commander of Discovery's STS-114 mission, told reporters here at Kennedy Space Center's Shuttle Landing Facility. "We're hoping that this weather holds through next week."
Collins eased her T-38 jet to a stop on the tarmac at about 11:45 a.m. EDT (1545 GMT). At the same time, Discovery pilot James Kelly halted his own T-38 aircraft with mission specialist Charlie Camarda in the back seat. STS-114 mission specialist Wendy Lawrence accompanied Collins during the flight from Houston, Texas, where the astronaut conducted an ascent/entry training simulation Thursday.
The arrival of some STS-114 astronauts was delayed. NASA officials said that the T-38 aircraft carrying STS-114 mission specialists Andrew Thomas, Soichi Noguchi and Stephen Robinson had to return to Ellington Air Force Base to switch planes after they developed some in-flight problems.
"We had some mechanical problems with a couple of the planes," Thomas said. "We always have back ups with us and just swapped out."
Collins and her fellow Discovery astronauts are slated to launch spaceward at about 10:39 a.m. EDT (1439 GMT) on July 26. Their flight has been delayed since July 13, when launch controllers scrubbed the attempted space shot after a liquid hydrogen fuel sensor failed a standard countdown test. Since then, engineers have worked around the clock to isolate and fix the glitch, and are targeting two potential sources that include electromagnetic interference from cameras, heaters or other hardware aboard Discovery and its external tank, as well as a grounding issue with wiring aboard the orbiter.
"We are very proud of the work that the engineers, technicians and managers have done to try and figure out this problem," Collins said, adding that she and her crew have been listening in on technical briefings and following the troubleshooting efforts.
Engineers have been tracing a glitch in the engine cut-off (ECO) sensor system inside the liquid hydrogen compartment of Discovery's external tank. One of the four sensors failed to properly report a 'dry' status - indicating the tank was empty of fuel - during a countdown test. Under current flight rules, all four sensors are required to perform properly since they ensure Discovery's three main engines shut down before its fuel tanks run dry. If the engines continue firing once the tank is empty, they could rip apart the shuttle.
The STS-114 astronauts are NASA's first slated to ride a shuttle into orbit since the 2003 Columbia disaster that claimed the lives of seven astronaut and destroyed one orbiter.
While the engineering investigation has pushed Discovery's launch further into its flight window - which closes on July 31 - Collins said that safety, not scheduling, is paramount.
"The launch date, to us, isn't that important...what's important to us is that we get through this process and do it right," Collins said. "We're really excited about getting this launch off. We'll be talking to you from space."
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