Also Pushes Off ISS Repositioning Due To Glitches
During a review of space shuttle Discovery's readiness for
flight, NASA managers decided Tuesday to plan a launch no earlier
than February 19 -- one week later than original targets.
The new planning date is pending additional analysis and
particle impact testing associated with a flow control valve in the
shuttle's main engines. The valve is one of three that channels
gaseous hydrogen from the engines to the external fuel tank.
NASA found one of those valves damaged in Endeavour after that
shuttle's mission in November. As a precaution, Discovery's valves
were removed, inspected and reinstalled. It's not clear yet what
the nature of the problem is.
The Space Shuttle Program will convene a meeting on February 10
to assess the analysis. On February 12, NASA managers and
contractors will continue the flight readiness review, which began
Tuesday, to address the flow control valve issue and to select an
official launch date.
Discovery's STS-119 mission to the International Space Station
will deliver the last set of solar arrays needed to supply
electricity to support a full crew complement onboard the station.
The first six-person Expedition to the ISS is slated to be in place
later this year.
NASA also disclosed Tuesday a planned repositioning of the ISS
has been put off until March, after problems arose during a similar
exercise last month. Russian engineers sent commands for the
rockets on the Zvezda service module to fire, to place the station
in a higher orbit in anticipation of a February resupply mission...
but those commands contained errors, which resulted in the rockets
cutting off suddenly.
USA Today reports the resulting jolt to the station was outside
normal parameters, and may have caused structural damage to the
station. While the station was designed to handle
higher-than-expected structural loads, NASA is now conducting an
analysis to determine whether the incident may have "eaten into
that margin," according to NASA spokesman Kelly Humphries.
Due to the station's low orbital position, repositioning rocket
burns are used regularly to lift the station further from the pull
of Earth's gravity.