Improved Shuttle to Resurrect America’s Adventure in Space

As the tragedy that was the Challenger slips further and further into the reaches of the mind where memory assigns those events it would like to forget, the great adventure is about to begin anew.

And it falls to a bird called Discovery to heal the wounds from a catastrophic day, allowing the nation to return to an arena in which it once reigned supreme.

With each passing day a little more progress is made, enhancing the chances that sometime toward the end of August the three powerful engines on the Discovery, and the two solid rockets bolted to its side, will fire, sending shock waves through the ground and the air, shaking buildings many miles away, forcing strong men to hide their watery eyes.

But many who were there more than two years ago to watch the Challenger blast off will not be there when the Discovery once again attempts to carry mortals beyond the Earth.

For them, the agony of that cold morning will last a lifetime.

They range from Jesse Moore, then head of the shuttle program, who has since slipped into obscurity, to the countless men and women who worked behind the scenes to bring the shuttle into an era of “routine operations.”

“We had some people say, ‘I don’t want to be on the firing line, or under the spotlight, for the next launch. I’ll back off a little bit,’ ” said Robert B. Sieck, the man who is directing the launch of the Discovery. “I consider them casualties because we lost them from the active part of the team.”

“It was tough,” Sieck said. “But people got over it. They won’t ever forget it, but they got over it. We’re not quitters.”

200 Modifications

In the last 2 1/2 years, Sieck and his colleagues in the National Aeronautics and Space Administration have made more than 200 modifications in the space shuttle, reorganized their management structure, redefined their launch restrictions and made scores of other changes to lessen the chance of another disaster like the Challenger.

Only time will tell if they have succeeded, but few who have followed their efforts doubt that the space agency and its program have changed significantly. When the Discovery lifts off from launch pad 39B at the Kennedy Space Center, it will be launched by a far more cautious--some would say timid--NASA.

Could tragedy strike again?

“The probability is certainly much lower,” Sieck said, mindful of the fact that space travel will never be without risks.

Would the changes that have been made have prevented the launch of the Challenger on a morning when frigid temperatures had weakened the seals in its solid rockets, paving the way for disaster?

“Oh yeah,” Sieck said quickly. “There’s no question about it.”

Concerns Go to the Top

The concern about the cold weather, now known to have compelled some engineers to try to stop the launch because they feared the seals would not hold, “would have made it right up to the top,” he said.

Dozens of people will have the authority to stop any launch in the future. Furthermore, the shuttle cannot be launched without the specific authority of a man who has been there before, Rob1701999648missions, including the first flight of the space shuttle seven years ago.

Crippen does not duck the fact that he will shoulder much of the responsibility for firing off rockets that will carry his colleagues into space.

“I am the person down at the launch site” who will make that decision, he said in an interview at the Kennedy Space Center.

“We will go into a mandatory hold at 9 minutes (before launch),” said Crippen, one of the most respected members of the astronaut corps.

Crippen, who is now deputy director of operations, has about two dozen members on his “mission management team,” and each is an expert in a different area.

“Every member of that team has a ‘no go’ button,” Sieck said.

Final Authority

The team’s final authority will rest with Crippen.

“I will give him (Sieck) a ‘go or no go,’ ” Crippen said.

Crippen was shocked by some of the revelations that surfaced during the presidential commission investigation that probed the Challenger accident, especially the fact that past problems with the joints were known to some NASA engineers but not to the astronauts who fly the shuttle.

His new role fills a void cited by the commission, which called for greater participation by astronauts in management of the program.

Crippen’s very specific responsibility, plus a narrowed focus for Sieck, should make the system safer, but it also means that launches in the future could be delayed more often than those in the past, some NASA sources believe.

Sieck insisted that changes in the management structure will not introduce extended delays “if the hardware is good to us,” but he admitted that much more stringent “weather criteria” could mean frequent delays. That could be important because of a growing backlog of missions, and some fear that NASA could find itself once again trying to meet an unrealistically demanding launch schedule.

Contributed to Disaster

An effort to meet such a schedule has been cited repeatedly as contributing to the Challenger disaster.

“Weatherwise, the potential is certainly there” for frequent delays in the future, Sieck said. “The launch criteria will be much more conservative.”

For one thing, the weather will have to be warmer. The Challenger exploded because cold temperatures lowered the resilence of the rubber seals in the joints of the solid rockets, allowing hot gases to escape from one joint and setting off the explosion.

“It looks like it will have to be (at least) somewhere around 40 degrees, but that still hasn’t been set,” Sieck said.

Cold weather is the exception rather than the rule in Florida, but other restrictions would seem to have great potential for delay, considering the normal weather patterns for that area. An Atlas Centaur rocket, launched a few weeks after the Challenger explosion, had to be destroyed after it was struck by lightning, and that has prompted NASA to prohibit launching whenever there is a chance that the shuttle would have to pass through cloud formations capable of producing lightning.

New Restrictions

“We will not be allowed to launch through any layered clouds,” Sieck said. “In the past, we could launch on a day that appeared overcast as long as we had no thunderstorms directly in the vicinity. Now, if we have any clouds that are over 4,500 feet thick that are near or above freezing level, the probability for triggered lightning exists because of (electrically charged) particles in those clouds, even if there’s no rain in them. So we won’t be able to launch, and that’s new. It’s restrictive.

“If we have any shower activity within 20 miles of the launch pad area, and if those clouds show any potential for building into a thunderstorm, that will cause us to hold. And that’s new.”

Another restriction that is likely to cause the most delays sounds almost like a description of a typical summer day in central Florida, Sieck conceded. If thunderstorms have hit even as far away as Tampa Bay, which is about 110 miles away and on the other side of the state, “and if debris (clouds) from that active thunderstorm are anywhere in the area at all, we will not be able to launch,” he added.

“In the summertime, it will probably be that rule” that will force delaying the launch the most often, he said.

Most flights require that the shuttle be launched during a specific “window” so that its orbit serves the needs of the mission, so a delay of even an hour or two because of weather usually stretches into a delay of at least a full day.

A Different Vehicle

When it does finally begin flying again, the space shuttle will be a different vehicle in many ways than it was in the past, and some of the changes brought on by the Challenger may have prevented an accident that was waiting to happen.

For example, one of the most vulnerable components of a solid rocket motor is the nozzle that must channel the rocket’s enormous thrust. If the nozzle fails on one rocket, the thrust from the other would cause the shuttle to cartwheel. The nozzles must also be able to swivel during liftoff so that the spacecraft can be controlled, and their ability to do so depends partly on protecting nozzle bearings from the heat of the rocket.

In examining the boosters recovered after the Challenger accident, NASA found that an insulating “boot” that protects the bearings had been damaged. Although there is no indication that the damaged boot contributed to the accident, it has been redesigned for future flights.

In addition, the joint between the nozzle and the rocket was found to be unsatisfactory and has been strengthened.

“That would have caught us eventually if we had kept flying,” Crippen said.

The joints between the segments of the rockets have also been redesigned.

We Didn’t Understand’

“The bottom line is we found that we really didn’t understand how that joint was operating,” Crippen said.

The joints now have a “capture” lip to make them fit tighter, plus additional seals and O-rings that prevent the hot gases from escaping through the side of the rocket. And, small heaters consisting of fine wires that carry electricity have been added to the joints, thus minimizing the effects of cold temperatures.

Other changes include an improved landing system, designed to overcome nearly constant problems with the shuttle’s brakes, improved valves in fuel lines to prevent a premature closure that would shut off fuel, and an emergency escape “pole” that would allow astronauts to climb free of the vehicle and parachute to the ground if it should become necessary to escape just before landing.

“We have made something like 200 individual changes on the orbiter,” Crippen said. “We are testing them all to make sure we haven’t done something dumb.”

Extensive testing--including firing redesigned rocket motors with intentional flaws--has reassured NASA engineers that they are on the right track, Crippen said.

The tests, he said, are “the essence of why we are going to feel really good when we start flying again.”

More Landing Sites

NASA has also added additional emergency landing sites around the world in case the shuttle has to abort sometime after launch.

The 2 1/2 years that the shuttle has been out of service have also given NASA engineers time to correct a few problems on the ground.

There is, for example, the long runway at the Kennedy Space Center where NASA had hoped to land the shuttle after most flights. When it rains in Florida it can be serious business, so NASA had the runway grooved so rainwater would run off. No one wanted to see astronauts try to land a giant glider like the space shuttle on a river of water.

“We ended up with the driest runway in the country,” Crippen said.

There was only one problem. The grooves in the runway ripped the shuttle’s tires to shreds. So workers have painstakingly ground off the grooves, providing a smooth runway.

Ironically, the shuttle will not be landing at Kennedy anyway when it is raining because weather restrictions would force NASA to shift the landing to Edwards Air Force Base in California. So the grooves were not necessary.

Except for an emergency immediately after launch, the shuttle will not be landing at Kennedy for some time in the future. A more safety-conscious NASA has decided to use the more forgiving conditions at Edwards instead of the fickle situation at the Cape, where weather can change quickly and alligators lurk alongside the runway.

Bordering on Ludicrous

Other concerns over safety, although easily understood in the aftermath of the Challenger, have brought about a change in the way the space agency does business that some observers believe borders on the ludicrous.

It took nearly six weeks, for example, for workers to stack the solid rocket segments that will be used on the Discovery. The same process used to take a few days.

The extent of the concern over safety was demonstrated when the last segment was being “mated” to the second rocket a few weeks ago. While preparing to bolt that segment in place, workers discovered a scratch in the joint about the size of a human hair.

The mating was delayed for nearly two full days while workers polished the joint until the scratch disappeared.

“Imagine, this is a rocket as tall as a 14-story building, and it was delayed two days because of a scratch the size of a human hair,” one official lamented. “It’s meaningless,” he said, suggesting that engineers are so worried about insignificant flaws that there is little chance the shuttle will be launched as soon as NASA hopes.

Most Critical Test

But progress continues to be achieved at the Kennedy Space Center. The solid rockets have been attached to the 78,100-pound external tank that carries the fuel for the shuttle’s on-board engines. If all else goes according to plan, the shuttle will be rolled out to the launch pad later this month and, on about July 19, its main engines will be test fired in what is probably the most critical test remaining.

Then, sometime around the end of August, veteran astronaut Frederick H. Hauck will lead his crew--Richard O. Covey, John M. Lounge, George D. Nelson and David C. Hilmers--into the Discovery.

Several thousand reporters and photographers will record the event. People around the world will watch. And all will remember another day, not so long ago, when a ship called Challenger stood on the same pad.