Blast Came Too Early for Rescue, NASA Says : Crew Can’t Escape Because of Burning Rockets During First 2 Minutes, 6 Seconds of a Flight

Despite conjecture that the space shuttle Challenger’s crew might have had some hope of survival if there had been warning of pending disaster, NASA officials insisted Monday that there was no chance of a rescue so early after liftoff.

In the first 2 minutes and 6 seconds of flight, while the two giant booster rockets do the main work of propelling a shuttle into orbit, there is simply no way to jettison the rockets and escape, the officials said.

The Challenger was destroyed in a fiery explosion 73 seconds after it was launched, killing the seven crew members.

In a television interview Sunday, acting NASA Administrator William R. Graham did not completely rule out the possibility that the crew members might have been able to attempt to free themselves from the rockets that propelled their spacecraft. But he noted the enormous difficulties involved.

No Practical Way

Others at the National Aeronautics and Space Administration say that there is no practical way to carry out such a maneuver.

“No one trains for or plans for that contingency,’ said Brian Welch, a NASA spokesman at the Johnson Space Center here.

That is one reason why NASA officials decided to remove sensing devices planted in the booster rockets on earlier flights, according to Welch and others.

Once ignited at the moment of liftoff, the two 149-foot-long booster rockets cannot be turned off, he noted. Filled with a rubberlike solid fuel, the boosters have often been compared to fireworks--they burn until their fuel is exhausted.

Abnormal Plume

Films of last week’s ill-fated Challenger launch show an abnormal plume of fire escaping from the shuttle’s right booster engine 13 seconds before the explosion. NASA sources say it is believed that the flame from the booster led to the explosion of the shuttle’s main fuel tank.

In a normal flight, the boosters separate from the orbiter and its fuel tank after the booster rockets have stopped firing.

As designed, the separation cannot take place any sooner, said another NASA spokesman, Robert T. White.

“You’re captive to the system,” he said. “How do you get off that beast while it is burning?”

As a practical matter, shuttle and ground crews realize that they cannot alter a shuttle launch for a full 2 1/2 minutes after liftoff, said Brian D. Perry, a NASA flight dynamics officer.

Would Lose Control

Until that time has elapsed, overriding the shuttle’s automatic controls would mean losing control of its flight path and would be too dangerous, Perry said.

“We (shuttle and ground crews) don’t spend time training on the first two minutes,” he said. “It doesn’t do the crew any good to assume a case where the end result is the loss of the vehicle. The solids (solid fuel rockets) have to work.”

Perry was responsible for the decision to abort an earlier Challenger launch last July--the only time in the history of the American manned space program when such a procedure was carried out in flight. In that case, a faulty heat-sensing device automatically triggered a shutdown of one of the shuttle’s three main engines almost six minutes after liftoff.

But on that mission, the shuttle was high enough and moving fast enough to carry out a maneuver called “abort to orbit”--reaching an orbit closer to the Earth than originally planned.

Training Pays Off

The resolution of that incident seemed to show that the many hours of prelaunch training and flight simulation had paid off, and it lifted confidence that NASA could avert a catastrophe, even after a major malfunction. The Challenger completed eight days in orbit, and the crew was able to finish its work assignments.

However, space agency officials began to acknowledge that under slightly different conditions, things might not have gone quite so well.

If the engine had failed earlier in that July flight of the Challenger, the shuttle might have been forced to land in Europe or Africa, or complete a complicated acrobatic maneuver that would have sent it back to its Florida launch site.

Ocean Landing

And if a second main engine had been shut off, as the shuttle’s computer system was threatening to do because of another set of defective heat sensors, the Challenger would have been forced to attempt an ocean landing.

That would have been a risky procedure.

“Basically the (shuttle) orbiter is not a good ditcher,” explained chief flight director Tommy W. Holloway at a press briefing last August. “It lands very fast and it stops very fast, and when you stop very fast you incur a lot of deceleration. So the prognosis is not very good if you incur an orbiter ditching.”

Even that option was closed to last week’s Challenger crew.