Discovery Gets "Go" for Tanking

Space shuttle Discovery's orange external tank will be loaded with about 500,000 gallons of super-cold propellants during a three-hour process that will begin at 4:11 p.m. The careful procedure will start with "chilldown" which conditions the pipes for the flow of liquid hydrogen at minus-423 degrees and liquid oxygen at minus-297 degrees. The chemicals power Discovery's three main engines during the 8 1/2-minute launch into orbit. Liftoff remains on schedule for 1:36 a.m. Tuesday, and the chance of acceptable weather conditions is 80 percent.