Cryogenic propellants are flowing into space shuttle Discovery’s external fuel tank this morning as the countdown to this afternoon’s launch moves ahead. Liftoff time set for 4:50 p.m. The launch team performs the fueling operations by remote control from the Launch Control Center. The first phase of the fueling is called “slow fill” to allow the pumps, lines and tank to condition themselves to the super cold chemicals. The liquid oxygen is at minus-297 degrees F and the liquid hydrogen is at minus 423 degrees F. The propellants are used by the shuttle’s three main engines at liftoff.
Teams are not working any issues that would delay today’s liftoff.
This will be the last mission for Discovery, which has made 38 prior trips to space.