Fuel Cell Glitch Scrubs Atlantis Shuttle Launch

[pizzaman777]

Delays, delays and more delays... <_<

Quote:CAPE CANAVERAL, Fla. – Six astronauts and NASA’s shuttle Atlantis will have to wait at least one more day before launching toward the International Space Station (ISS) while engineers puzzle a fuel cell glitch aboard the spacecraft.

Atlantis’ launch is now reset for no earlier than Thursday at 12:03:03 p.m. EDT (1603:03 GMT) as shuttle specialists tackle a voltage issue with one of three fuel cells which generate the electricity to power the shuttle during its 11-day ISS construction mission. The shuttle’s launch window closes Friday.

“We were ready to go,” NASA spokesperson Bruce Buckingham said here at the Kennedy Space Center (KSC), where Atlantis stands poised to launch at Pad 39B. “We were just waiting.”

NASA mission managers held off fueling Atlantis’ 15-story external tank with cryogenic liquid oxygen and liquid hydrogen propellant – originally slated for 2:30 a.m. EDT (0630 GMT) – while discussing the fuel cell glitch, which first appeared as engineers powered up the shuttle before 1:30 a.m. EDT (0530 GMT) this morning. Atlantis was slated to launch its STS-115 mission at 12:28:46 p.m. EDT (1628:46 GMT) today.

“We held off as long as we could,” Buckingham said. “We’re going to troubleshoot this, see if we can understand what happened and when we can rectify it.”

A voltage spike in the alternating current of Fuel Cell 1 prompted the concern, NASA officials said, adding that the short occured in a coolant motor for that unit. According to NASA flight rules, all three of Atlantis' fuel cells must be functioning properly before the shuttle can launch. Engineers are drawing up options to work around, repair or replace the hardware, shuttle officials said.

Shuttle managers scrubbed Atlantis’ Wednesday launch for at least 24 hours to give engineers more time to study the fuel cell issue. The shuttle had a 70 percent chance of favorable launch weather today and is expected to have the same odds over the next two days.

Shuttle managers will gather at 1:00 p.m. EDT (1700 GMT) today during a Misison Management Team meeting to discuss Atlantis' options. A press briefing is expected to follow that discussion.

By calling off today’s launch attempt before loading Atlantis’ shuttle fuel tank with its 526,000 gallons of super-cold fuel, NASA does avoid the typical $600,000 cost of a scrub after tanking is complete, Buckingham added.

Atlantis’ STS-115 mission – commanded by veteran shuttle astronaut Brent Jett – is aimed at delivering a $371.8 million pair of massive portside trusses and two new solar arrays to the ISS. The spaceflight will mark NASA’s first dedicated ISS construction effort since the 2003 Columbia accident and follows two return to flight test missions.

The last major piece of ISS hardware – the Port 1 (P1) truss – launched aboard NASA’s Endeavour orbiter during the STS-113 mission in late 2002. Atlantis’ Port 3/Port 4 (P3/P4) trusses are destined to be installed at the end of their P1 cousin.

Today's scrub follows several delays for Atlantis' STS-115 mission, following a lightning strike to the shuttle's launch pad and storm threats from a tropical depression last month.....

http://space.com/missionlaunches/060906_st...aunchscrub.html