NASA Discusses Launch Options for Shuttle Discovery

by James Dean, FLORIDA TODAY

Date: 20 February 2009 Time: 09:54 AM ET

NASA Moves Shuttle Launch Target Up to March 11

Space shuttle Discovery rests on Launch Pad 39A after a seven-hour rollout from the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida on Jan. 14, 2009. The shuttle is slated to launch no earlier March 12.
CREDIT: NASA/Troy Cryder.

NASA will decide today if it's safe to launch shuttle Discovery next Friday on an International Space Station assembly mission.

During a flight readiness review scheduled to start at 9 a.m., top managers and engineers will pore over data collected from weeks of testing on propulsion system valves that, if damaged, could put astronauts at risk as they rocket into orbit.

They'll determine whether the risk is acceptable for at least one mission while tests continue.

"It will be dependent on where the data leads the teams, and whether everyone can get comfortable with a one-flight rationale," NASA spokesman Kyle Herring said.

The three flow-control valves work like pop-up lawn sprinklers to route gaseous hydrogen from the shuttle's main engines through a line to the external tank's liquid hydrogen reservoir, maintaining its pressure as the fuel is consumed.

The lip of one valve broke off during Endeavour's launch in November, raising new concerns that failed valves could rupture the gaseous hydrogen line or over-pressurize the tank.

Those events could cause an explosion or early shutdown of the main engines.

Engineers at five NASA centers conducted impact tests and developed computer models to better understand worst-case scenarios and their probability.

Today's review resumes one that began Feb. 3, when Discovery was targeted to launch Feb. 12.

The decision was made then to put off the launch to continue testing the valves.

A news conference to announce today's conclusions is planned no earlier than 5 p.m.

During a planned two-week mission, Discovery's seven astronauts will install the last piece of the space station's central backbone and deploy a final set of American solar array wings.

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