Decision Day: Feb. 22 Launch Date Up For Debate

NASA is expected to decide today whether to continue pressing toward a tentatively scheduled Feb. 22 launch for shuttle Discovery after senior managers are briefed on an ongoing series of main propulsion systems tests.

Senior shuttle program managers will gather at 11 a.m. EST to hear a status report on tests aimed at determining whether it's safe to launch Discovery and seven astronauts despite the failure of a critical main propulsion system valve during Endeavour's launch last November.

Tests at five NASA facilities in five states are being conducted to determine whether debris liberated from a cracked gaseous hydrogen flow control valve could rupture main propulsion system lines and cause a drop in pressure in the hydrogen reservoir within the shuttle's external tank during ascent.

Proper pressure is required to feed fuel into the shuttle's three main engines; a pressure drop could lead to an engine shutdown or breakup in flight.

One of three GH2 flow control valves failed to operate properly during Endeavour's launch; post-flight inspections showed the lip of the valve -- which is about the size and shape of a lawn sprinkler -- cracked in flight.

Today's meeting is expected to last several hours. Managers will hear reports on the status of tests at Johnson Space Center in Houston, Stennis Space Center in Bay St. Louis, Miss., Marshall Space Flight Center in Huntsville, Ala., Glenn Research Center in Cleveland, Ohio, and White Sands Test Facility in New Mexico.

A decision on whether to proceed with a formal flight readiness review on Feb. 18 is expected at the conclusion of the meeting. Discovery's seven astronauts would go into quarantine at Johnson Space Center on Sunday in that case.

Managers also could decide more testing, or a valve redesign, is required. The Feb. 22 target launch date would be pushed back in that case.

The launch had been targeted for Feb. 12 and then Feb. 19 before being delayed until No Earlier Than Feb. 22. Discovery's astronauts aim to deliver the last section of the International Space Station's central truss. The 31,000-pound S-6 truss is equipped with the station's fourth and final set of American solar wings.


ABOUT THE IMAGE: Click to enlarge and save the NASA image of Discovery ilhouetted against the dawn's early light as it rolled out to Kennedy Space Center's launch pad 39A in January. The shuttle is shown sitting atop a mobile launcher platform that is being hauled to the pad by a massive crawler-transporter. Photo credit: NASA/Troy Cryder.