NASA to forego tanking test

Shuttle Discovery's modified external tank will not be put through a fuel-loading test prior to its planned July 1 launch on NASA's second post-Columbia mission.

In a meeting today, senior managers decided that all the objectives of such a test could be accomplished when the tank is loaded with more than 500,000 gallons of liquid hydrogen and liquid oxygen in the hours leading up to a July 1 launch attempt.

NASA managers had given engineers a go-ahead to put in place all the preparations that would have been necessary to carry out a tanking test on June 1.

The exercise would have given NASA the opportunity to test new fuel-depletion sensors that were installed in the tank after its delivery to Kennedy Space Center earlier this year.

Sensor data during a three-hour fuel-loading operation and subsequent pressurization of the tank prior to Discovery's launch will show whether the so-called Engine Cut-Off sensors are working properly. A launch countdown can be halted if they are not.

NASA inspections after a fuel-loading test last year showed that filling a 15-story tank with supercold propellants could cause small defects within foam insulation that keeps ice from building up on it.

Such defects could lead to the type of foam loss blamed for the February 2003 Columbia accident, which killed seven astronauts.