2003年2月1日
NASA Vows to Find Cause of Shuttle Disaster
by By Jeff Franks, Reuters
Saturday, February 01, 2003 10:29 p.m. ET
========================================================
JOHNSON SPACE CENTER, Texas (Reuters) - Shaken NASA officials vowed to find out what caused the space shuttle Columbia to break up over Texas on Saturday, saying they would look closely at the impact of a piece of foam insulation that struck the orbiter's left wing at takeoff.
They said the shuttle was just 16 minutes from landing at Kennedy Space Center in Florida and gliding along smoothly when sensors began failing, signaling that something was wrong.
"We lost data and that's when we clearly began to know that we had a bad day," Ron Dittemore, the agency's space shuttle program manager, told reporters as he fought back tears. "We're devastated."
Columbia, the oldest shuttle in the U.S. fleet, disintegrated 40 miles above northeastern Texas, showering the region with debris and killing the seven astronauts on board.
Dittemore said a piece of foam insulation came off the shuttle fuel tanks at liftoff on Jan. 16 and banged into the spacecraft's left wing, but was judged by ground controllers not to have damaged the orbiter's critical heat shield.
But on Saturday, after the Columbia had re-entered the earth's atmosphere to head home from its 16-day scientific mission, sensors in the left wing began to fail in a possible indication that excessive heat was seeping into the shuttle structure, he said.
At the time that Columbia came apart, its wings were heated to 3,000 degrees Fahrenheit, but the heatshield should have prevented damage to the shuttle, Dittemore said.
"Now, in hindsight, that impact (of insulation) was on the left wing. All the indicators (of trouble) were on the left wing. We can't discount that there might be a connection, but we can't rush to judgment on this," he said.
He pointed to a critical vulnerability of the shuttles, saying that if they do suffer heatshield damage at launch, nothing can be done about it.
Astronauts cannot make repairs and there are no flight maneuvers that can reduce the heat of reentry, caused by friction with the earth's atmosphere.
"There was zero we could do about it," Dittemore said.
He said flying insulation was seen on a shuttle launch last year, but did not affect the flight.
The shuttle program's other disaster, the explosion of Challenger shortly after launch in January 1986, was linked to fuel tank problems. In that case, a gasket failed, causing the fuel to ignite in a blast that killed the seven astronauts on board.
Dittemore said NASA was sending experts to northeast Texas to help in the search for shuttle parts. They would be rounded up for investigators to study for clues to the disaster.
NASA also said it would treat the investigation much like an aviation accident and enlisted help from government transport and aviation safety experts.
The National Transportation Safety Board, which investigates plane crashes, said it had assigned five investigators at the space agency's request.
They are experts in reconstructing and analyzing debris fragments and evaluating the performance of flight systems, like hydraulics and electronics.
"We have offered whatever assistance we can provide," safety board spokesman Ted Lopatkiewicz said.
A Federal Aviation Administration accident investigator will also participate in the probe, the agency said. That official could seek help from other agency investigators, if needed, a spokeswoman said.
The Transportation Department will also contribute at least one expert from its advanced systems research facility in Cambridge, Massachusetts.
Included on the flight was Israel's first astronaut, Ilan Ramon, which raised fears that the shuttle may have attacked or sabotaged, but NASA officials said there was no indication of that.
Dittemore said NASA would ground the three remaining shuttles until it figured out what happened and fixed the problem.
"My impression is we are going to gather every piece we can find, treat this much like an aircraft incident and see if we can solve the puzzle," Dittemore said.
He said some evidence may have burned up during re-entry. "Other debris is just spread over such a wide territory that we may never find it," he said.
Grounding the other shuttles could affect three astronauts currently on the International Space Station, who are ferried home by the shuttle. He said they would have enough food to stay on the space station until June, but a NASA spokesman said they could be brought back by a Russian Soyuz spacecraft if necessary.
========================================================
No wonder the National flag was half-mast on top of the Sapce Needle today.
God bless you all, dear astronauts!!
posted by Biochemie on 8:09 下午
0 comments
__________________________________________________________________
|
