There is now only a 40% chance that storm clouds in the Florida region will delay the planned 1948GMT launch of Space Shuttle Discovery for its International Space Station (ISS) logistics mission STS-121.
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| Space Shuttle Discovery sits at Launch Complex 39B as its fuelled on the morning of 1 July 2006. |
This second return to flight mission will see supplies delivered, European Space Agency astronaut Thomas Reiter transported to the ISS for his six month mission, replacement of a pump and a communication umbilical reel assembly for the ISS’s mobile transporter fitted, and Shuttle thermal protection system tile repair techniques tested.
At 1000 today work began to load the Shuttle’s propellants, liquid oxygen and liquid hydrogen, into its external tank (ET)-119, which weighs 727,000kg (1.6mlb) when full. That was completed at 1300.
Because the ET’s 500,000 gallons of cryogenic fuel boil off, propellant will be fed to the ET up to launch.
NASA had concerns about the ET’s Engine Cut Off sensors, due to problems in the run up to the launch of Discovery/STS-114 last year.
These sensors detect fuel levels to help determine when main engine cut off should occur. They had, before STS-114’s launch, given anomalous readings but none have been detected so far today.
At 1400 NASA launch managers were dealing with a failed thruster heater in the Shuttle's left orbital maneuvering system pod but they still expected to launch on time. There are no other reported technical issues with the Orbiter.
If the launch is delayed from today the weather is expected to deteriorate over the following two days. Discovery’s crew is expected to board the Shuttle at 16.30.
By Rob Coppinger in Orlando
Source: Flight International
