NASA Prepared to Ignore Red Light
26th July, 2005
Jul. 26--NASA is set to launch the space shuttle Discovery at 10:39 a.m. today -- with officials prepared to fudge a safety requirement that forced the agency earlier this month to scrub the launch after the crew was already strapped in and ready to go.
After 10 days of study by 14 engineering teams across the country, NASA says it still isn't sure what caused a sensor in the shuttle's external fuel tank to give a faulty reading during the countdown two weeks ago.
And they say they won't know whether the issue is resolved until the fuel tank is filled with 385,000 gallons of liquid hydrogen and 143,000 gallons of liquid oxygen sometime around dawn this morning.
Tests at the Kennedy Space Center launch pad have been unable to duplicate the earlier failure.
NASA managers say several alterations may have solved the problem, but even if it resurfaces they say they are now confident that it will not pose a threat to the safety of the mission.
As a result, they are prepared to waive launch safety criteria requiring that all four of the tank's hydrogen fuel sensors, electronic gauges that prevent an abrupt cutoff of the shuttle's main engines, be in working order for a launch. Three sensors, NASA now says, will be sufficient.
"There's very little in life that's 100 percent certain and there's probably even less in rocket science that's 100 percent certain," said shuttle deputy program manager Wayne Hale. "This is part of the risk we take."
"We have literally run every check that we could think of," Hale said. "We don't think the problem is in the sensor itself, but we have to go to cryogenic [cold liquid fuel] temperatures to find out what's going on next."
Discovery, with a crew of seven, is poised to make the first shuttle flight since its sister ship Columbia disintegrated over Texas, killing the seven astronauts on board, on Feb. 1, 2003. Discovery, commanded by astronaut Eileen Collins, will spend 12 days in space, transporting badly needed supplies to the International Space Station and testing new safety measures and modifications designed to prevent a repeat of the Columbia disaster.
In the months preceding the shuttle's long-awaited return to flight, NASA officials have repeatedly called the upcoming mission the "safest shuttle flight ever."
They also contend that a reorganization of NASA management has eliminated the "go fever" that in the past prompted the waiver of safety requirements to comply with a rigorous launch schedule.
During the early years of shuttle operations, NASA required only three of the four sensors to be in working order before launch. The current, more stringent requirement was imposed in 1986, after the Challenger exploded shortly after liftoff.
Neither the Challenger disaster nor the loss of the Columbia were related in any way to the fuel tank sensors, but after both disasters, investigators criticized NASA for granting too many safety waivers.
Hale said this time is different. Although at least one mission manager expressed concern about the decision to bend the rules, NASA officials say the team is now in agreement that the measure is justified.
"We have not changed the launch commit criteria," he said. "It is a deviation. If we are comfortable that we have a good understanding of the cause, then we can go fly."
NASA Administrator Michael Griffin has also said he is "comfortable with where we are" in assuring the safety of the mission.
Griffin, who was appointed to head NASA earlier this year, has reputedly said that space flight is "a risky business" and the agency's job is to see that the risk is within "acceptable" limits.
But Griffin has also pledged to Congress that he hopes to reduce the number of planned shuttle flights -- from 28 to as few as 15 -- between now and the time the shuttle fleet is due to be retired in 2010.