NASA Pondering Shuttle Escape Capsule

After a full year studying a variety of escape systems for the space shuttle, NASA is taking a harder look at what was considered the longshot: a flyaway capsule.

The idea would be to install ejection seats in the cockpit for the pilots and put a pod in the cargo bay for everyone else to sit during launch and landing, the most dangerous phases of any space shuttle flight.

In the event of an accident, the commander and co-pilot would eject from the shuttle in military fighter fashion. The three to five other astronauts would escape inside a pod that blasts out of the cargo bay and parachutes to Earth.

This is a long way from being recommended, let alone approved, and, like other escape options under consideration, may remain on the drawing board forever.

It would be expensive--hundreds of millions of dollars, possibly $1 billion or more--and take each of the four space shuttles out of action for retrofitting for a minimum of 1 1/2 years.

Johnson Space Center engineers in Houston ruled out the possibility of a flyaway capsule early in their $5-million study, the most expensive and extensive analysis of shuttle escape systems ever conducted by NASA. They were put off by the technical challenges and the intrusion into the cargo bay.

When the engineers presented their findings in April, with the focus on ejection seats, shuttle program manager Ron Dittemore told the group to take another, harder look at an escape capsule.

They will report back to Dittemore in July.

Two other options are still in the running: ejection seats for everyone on board, and a crew cabin that could separate from the rest of the shuttle in a launch or landing emergency and parachute to safety.

“I guess I would not like to make a choice right now because we want to chew on what we’ve got,” says Elric McHenry, manager of space shuttle program development.

He cautions: “If we ever do anything, it will have to be funneled through the administration and Congress because we’re talking about funds we don’t have.”

The Aerospace Safety Advisory Panel is pushing for a crew escape system--as soon as possible.

“There is no in-flight crew escape system for the orbiter other than for abort below 20,000 feet during a controlled glide,” the panel stated in its annual report in February.

That abort system, put in place after the 1986 Challenger disaster, calls for astronauts to blow the hatch, slide out on a pole and parachute, hopefully, to safety.

With NASA’s X-33 prototype space plane program dead and no shuttle replacement in sight, an escape system takes on added importance. Many insiders expect the shuttle fleet to keep flying well beyond 2012, increasing the likelihood of another catastrophe. NASA puts the odds of a launch disaster at 1 in 438.

Ejection seats--which could have saved the seven Challenger astronauts on shuttle flight No. 25--are hardly a new concept at NASA.

Columbia was outfitted with two ejection seats for the first four space shuttle flights, in 1981 and 1982. Each time, only two pilots were on board.

By the fifth flight, NASA had declared the space shuttle operational. Evacuation seats were no longer deemed necessary, and the crew size expanded beyond pilots.

For the first time in NASA history, in November 1982, a manned spacecraft was launched without means of escape. (The Mercury and Apollo spacecraft had rocket-powered towers to fling the capsules away in an emergency, and the Gemini capsules had ejection seats.)

NASA took back its claim of an “operational” space shuttle fleet after Challenger disintegrated 50,000 feet up.

Ejection seats could get astronauts out of a doomed shuttle from an altitude of 70,000 feet, maybe even 100,000 feet or more, McHenry says. A pressurized escape pod could descend safely from an altitude of more than 200,000 feet.

Those are the benefits.

But there are disadvantages, besides cost.

For starters, NASA’s astronauts are not thrilled with the idea of splitting a crew for launch and landing, or providing different escape capabilities for different crew members.

What’s more, bulky ejection seats would take up precious space in the cramped crew cabin. To install seven ejection seats would severely limit the astronauts’ ability to work in orbit, McHenry says.

McHenry says five ejection seats could be better accommodated. But reducing a shuttle crew from seven to five would hardly be popular in NASA’s 155-member astronaut corps. And it still would force NASA to cut payload weight by several thousand pounds.

A pressurized escape pod--considered by NASA as long ago as the 1970s--also would reduce payload weight. It would be a complex craft requiring life-support systems, and it probably would not help in a launch pad accident.

“You’ve put an escape system on that has to be its own spacecraft,” explains Kevin Templin, a project manager in the shuttle engineering office.

Making the crew cabin separable from the rest of the space shuttle would preserve the interior of the cockpit. But it too is a heavy option.

“It has the biggest impact on the vehicle because we’d have to modify the wings,” McHenry says. “Right now the vehicle couldn’t fly with that kind of mass up front.”

All of these escape systems would require explosive charges, and that too is a drawback. An accidental discharge could result in disaster.

Because of the time needed to modify each space shuttle, NASA would prefer waiting until the international space station is completed in 2006 before adding an escape system--if, indeed, one is recommended and approved.

“A very possible conclusion is that with the cost involved,” McHenry says, “there may be other ways we can improve crew safety that would be better spent.”

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NASA: https://spaceflight.nasa.gov