Technicians Load Shuttle's PRSD For Flight

Liquid oxygen and liquid hydrogen was loaded into Discovery's Power Reactant Storage and Distribution system Tuesday as the countdown for the STS-133 mission continues. Discovery is to lift off Thursday, Feb. 24, at 1650 EST.

The system, known by its initials PRSD, holds the chemicals for use in the shuttle's three fuel cells to produce electricity in space. The oxygen is also used to pressurize the shuttle's crew cabin. The combination of hydrogen and oxygen in the fuel cells produces a beneficial byproduct for the shuttle: water. Shuttle crews visiting the International Space Station routinely fill up bags with the water for use by station residents.

The same two chemicals, liquid oxygen and liquid hydrogen, are used by the space shuttle main engines at liftoff, but the propellants for that job go into the 15-story-tall external fuel tank and are not loaded until launch day.

STS-133 Commander Steve Lindsey and Pilot Eric Boe practiced landing approaches at the Shuttle Landing Facility on Tuesday in the shuttle training aircraft,  a Gulfstream II jet modified to simulate a shuttle's cockpit, motion and handling qualities. The rest of the crew conducted a review of orbiter ingress procedures.

FMI: www.nasa.gov