NASA managers have pushed back launch of the space shuttle Discovery on an assembly mission to the International Space Station until Feb. 27 at the earliest.
Discovery had been scheduled to fly on Feb. 22 with the fourth and final U.S.-built solar array wing for the ISS in its payload bay.
But engineers at NASA centers around the country need more time to finish testing whether a suspect gaseous hydrogen valve could break in a way that would hamper shuttle performance during ascent.
The valves - one in each of the orbiter's three main engines -- help keep the proper pressure in the hydrogen portion of the shuttle stack's big external tank. But after the STS-126 mission last year one of them was found to have ed and lost a small piece.
Engineers want to be sure that a similar mishap wouldn't damage the gaseous hydrogen lines between the orbiter and the external tank that keep the liquid hydrogen tank above 32 psi.
Managers have rescheduled the final flight readiness review for the mission on Feb. 20, and will hold a press conference afterward to report their findings and perhaps set an official launch date.
(Via On Space.)