Veteran astronaut Henry Hartsfield Jr. said today that he was "surprised and angry" to learn after the Challenger accident that there had been problems with the space shuttle's solid rocket booster seals on previous flights, including missions he commanded in August and November 1984.
"I personally was very upset to find out we had problems with the seals," said Hartsfield. "Apparently they had been causing trouble for some time. I was angry that I did not know this. There's nothing in writing that says the astronaut office must be made aware of such problems, but generally they do come to our attention."
The cause of the Jan. 28 Challenger explosion has not been determined, but a prime suspect is failure of rubbery O-ring seals designed to keep hot exhaust gases from leaking from between booster segments. Documents released after the accident and hearings of the presidential commission investigating it have revealed that the O-rings have been considered a serious problem at the National Aeronautics and Space Administration for at least three years.
Hartsfield was one of four space shuttle veterans who granted interviews to groups of reporters at the Johnson Space Center today, breaking five weeks of silence among the 95-member astronaut corps. NASA selected the astronauts to be interviewed, following numerous requests from the press for access to astronauts.
"I think we all feel we should have known," said Vance Brand, who commanded Challenger on a February 1984 flight. "We feel we are atop of most safety-of-flight issues. Somehow that one got by us."
Air Force Cols. Joseph Engle and Charles Fullerton, the other two shuttle veterans interviewed today, said they would not criticize the decision-making process in the Challenger mission. Although they, too, were unaware of the booster seal problems, they said they felt no need to know about every technical question concerning the shuttle mission.
"I know there are a lot of critical points in any launch," said Fullerton, who last commanded Challenger in August 1985. "But what can I do about this? I have a very complex machine to fly and to do procedures on, and that is enough for me to concentrate on. An astronaut has to work on faith. There is an implicit trust we have in the thousands of engineers and flight officers who make the go or no-go decision. It's not black and white. If we never left until everything was totally safe, we wouldn't have had one flight yet."
Nonetheless, Fullerton said he was placing his trust in the shuttle system "on hold" until the presidential commission finishes its inquiry into the Challenger accident.
Engle said he felt no lack of trust "either in the people or in the system." He said that even if there was a flaw in the handling of the Challenger launch, it would be revealed and discovered, and then "there will be one less thing that can go wrong."
While the three other astronauts praised the openness of the Rogers commission inquiry, Engle said that he would prefer a private investigation, and he criticized the "negative tenor" of the news coverage.
"The whole world is looking at us, and as Americans who fly in space, we enjoy the absolute adulation of the world, a little jealousy as a matter of fact," said Engle. "As Americans we can do anything. I think the world is looking to see whether we will take a positive attitude on this or curl up our tails and run into the corner."
All four astronauts said they considered NASA's procedures generally safe and cautious. They said they had never felt pressure to launch if conditions did not seem suitable.
Hartsfield recalled a shuttle mission in which he was allowed to poll his crew to determine whether they wanted to launch despite a minor problem, or wait one day and have it corrected. Hartsfield said that he voted to launch, but two of his crew members said they did not understand the problem, so, as commander, he asked that the flight be delayed.
Fullerton said he had been aware of the potential dangers of solid-fuel rocket boosters since 1968, when he saw an experimental booster rocket burn through its metal casing because of a lack of proper insulation. But the other astronauts said the booster rockets were about the last thing that concerned them on the spacecraft.
In a candid account of what goes through an astronaut's mind during the first few minutes in space, Hartsfield said:
"Those of us that have been in the business for a while are certainly aware of the risk. You're sitting on a lot of energy there that has to be controlled. You don't have to be very smart to figure out that the first 8 1/2 minutes of the flight are the riskiest. You've got the potential for disaster as you saw with the Challenger.
"In my own mind I assess the risk at two levels. My first goal was to get through the first two minutes because I knew that as long as the solids were on, I didn't have any abort capabilities. It's very tricky. Those first two minutes of flight I've just got to ride through.
"And after getting rid of the solids, my main worry was to keep the main engines running, at least to the point where I made orbit. I was never too fond of the idea of making an abort across the Atlantic. So all these things kind of go through my mind when I'm flying this thing and I find myself saying, 'Come on baby. Come on. Keep pumping.' "
The O-rings are washer-like seals placed at each joint of the segmented booster rocket. Each joint has a primary O-ring and a secondary, or backup, O-ring. In the past few years, there have been 17 instances during flight where there has been some erosion of primary O-rings, according to NASA documents.
As late as August 1985, the agency was told by Morton-Thiokol Inc., the booster manufacturer, that the backup O-rings had a "high probability" of complete failure if the primary O-ring failed during the ignition of the rocket. An internal Morton-Thiokol memo made public last week warned of a possible "catastrophe of the highest order" because of the problems with the seals.