Space shuttle Discovery stands on Launch Pad 39A on Tuesday evening after the second launch attempt was called off because of a problem with a fill-and- drain valve. Photo credit: NASA TV

NASA delays space shuttle Discovery launch

NASA managers postponed Friday's 12:22 a.m. EDT launch of space shuttle Discovery to allow engineers more time to develop plans for resolving an issue with a valve in the shuttle's main propulsion system.

Launch now is targeted for no earlier than 11:59 p.m. Friday, Aug. 28, from NASA's Kennedy Space Center in Florida.

During loading of the shuttle's external fuel tank for Wednesday's launch attempt, a liquid hydrogen fill and drain valve located in Discovery's aft compartment failed to provide the proper indication when it was commanded to close. Engineers cycled the valve five times Wednesday evening to collect data on the valve and its associated actuator and position indicator.

Nicole Stott, KE5GJN is one of three radio hams flying to the ISS on space shuttle Discovery

NASA managers decided Thursday that more time is needed to
analyze the test data and develop alternative procedures for confirming that the valve is closed
if the valve fails to provide the proper closed indication during Discovery's next launch attempt.

Discovery's 13-day STS-128 flight to the International Space Station will deliver storage racks; materials and fluids science racks; a freezer to store research samples; a new sleeping compartment; an air purification system; and a treadmill named after comedian Stephen Colbert.

Nicola Stott, KE5GJN is flying to the ISS and will replace Timothy Kopra, KE5UDN - who has been on the ISS since July.

There will then be six astronauts on board the ISS, with five of the six, including Stott, being licensed radio amateurs: Commander Gennady Padalka, RN3DT; Flight Engineer Michael Barratt, KD5MIJ; Flight Engineer Frank DeWinne, ON1DWN; Flight Engineer Robert Thirsk, VA3CSA.
Flight Engineer Roman Romanenko is the only one who is not licensed.

Discovery's crew will include José Hernández, KE5DAV and Swedish astronaut Christer Fuglesang, SA0AFS/KE5CGR.

Swedish ham astronaut to return to the ISS