Nasa said it is prepared to launch its first space shuttle mission since the Columbiaaccident two-and-a-half years ago even if a technical glitch that grounded the craft on July 13th reoccurs.
The launch of Discoveryis scheduled for 10:39am local time (3.39pm Irish time) on Tuesday, and is under intense scrutiny because of safety upgrades and other changes implemented after Columbiafell apart over Texas in February 2003, killing seven astronauts.
Michael Griffin, Nasa administrator
"We can't restrict the range of our options to those things which are going to present well necessarily," Nasa administrator Michael Griffin said.
Nasa flight rules require all four of the shuttle's hydrogen fuel sensors to be working before liftoff.
The instruments would shut down the shuttle's main engines before they run out of hydrogen fuel to avoid a potentially catastrophic explosion. The engine shutdown would occur if two of the four sensors register an empty tank.
When one sensor failed a routine prelaunch test during Discovery'sfirst launch attempt on July 13th, managers cancelled the flight, but tests failed to reveal the cause of the glitch.
Managers swapped the suspect sensor's connector with another sensor so that if the problem reoccurs, engineers will have more information about whether the sensor itself, the wiring or the electronics box is at fault.
If the tests assure managers that the problem is isolated to a single sensor, Nasa plans to waive its flight rule and launch the shuttle, provided all other systems and the weather is acceptable for launch.