NASA to review Discovery progress Friday

Senior shuttle program managers will meet Friday to assess progress testing valves that delayed Discovery's planned Feb. 12 launch, even though the tests won't be completed this week.

Friday's meeting will determine whether to proceed with an executive-level flight readiness review next Wednesday at Kennedy Space Center, or whether Discovery's current target launch date of Feb. 22 is likely to slip further.

Engineers at five NASA centers across the country are testing flow control valves that maintain proper pressure in the rust-colored external tank's liquid hydrogen fuel tank.

They want to determine whether an impact from a broken piece of valve could rupture the two-inch lines that route gaseous hydrogen between the shuttle's three main engines and its external tank.

One of the spark plug-sized valves failed during Endeavour's launch last November, but caused no damage.

The broken valve allowed a higher-than-normal flow of gaseous hydrogen, but the two other valves, closed down to compensate. The valves work like pop-up lawn sprinklers.

Proper pressure is critical to ensuring the tank doesn't rupture or prematurely cause the main engines to shut down.

Tests will continue at least through the weekend, with data being fed into computer models to further study potential problems.

After a roughly two-hour status report today, managers felt they had enough data to proceed Friday with a Program Requirements Control Board meeting that will update a broader group.

If they are confident in a flight rationale for Discovery despite the ongoing work, they could proceed with the flight readiness review next week.

So far, detailed inspections of the valves installed in Discovery showed no evidence of damage.

Discovery's seven astronauts are set to embark on a two-week mission to install a pair of American solar array wings that will complete the International Space Station's power supply.

IMAGE NOTE: Click to enlarge the image. On Jan. 14, space shuttle Discovery, atop the mobile launcher platform, reaches the top of launch pad 39A at Kennedy Space Center. At left is the White Room, attached to the end of the orbiter access arm. Behind the shuttle can be seen the Atlantic Ocean. Photo credit: NASA/Troy Cryder.