Thursday, July 7, 2011

Six to four move

Space Shuttle Atlantis astronauts, from left, Doug Hurley, Rex Walheim, Sandy Magnus and Chris Ferguson after a crew news conference at the Johnson Space Center in Houston last month.

"Only 4 Fliers for Last Shuttle Launch"


Kenneth Chang

July 6th, 2011

The New York Times

Normally, when NASA launches a space shuttle, there are either six or seven astronauts aboard. So why, on the 135th and final launching of the 30-year-old space shuttle program, will there be only four?

The answer, perhaps not surprisingly, has to do with the Atlantis’s being the last flight: With no spare shuttle available to go and rescue the astronauts in case something goes wrong, the Americans would have to turn to the Russians to retrieve their crew from the International Space Station. And the Russian spacecraft — known as Soyuz capsules — hold only three astronauts, so two people would have to fly up and bring home the Americans one at a time.

“This is a very low likelihood case,” Atlantis’s commander, Capt. Christopher J. Ferguson of the Navy, said last week during a news conference. But the agency’s safety experts have “done an extraordinarily thorough job of making sure we have a good plan to get home,” he said.

The Atlantis is scheduled to leave from here at 11:26 a.m. on Friday, making its 33rd flight. But the forecast on Wednesday was for only a 30 percent chance of acceptable weather, so the launching could be delayed until Sunday or beyond.

Otherwise, the countdown was proceeding smoothly. “There are no problems yet,” Michael P. Moses, the launching integration manager, said Wednesday at a news conference. “There are just weather forecasts.”

And about a million spectators are expected to show up.

NASA’s other two orbiters, the Discovery and the Endeavour, have completed their flying careers and are being primped for display in museums. The Atlantis was supposed to be retired now, too. NASA had prepared it as a rescue vehicle for the last flight of the Endeavour, in May, and it would have gotten off the ground only if the Endeavour had encountered trouble while in orbit.

But after spending hundreds of millions of dollars getting the Atlantis ready to fly, NASA officials said it made sense to fly it regardless, to carry additional supplies to the space station. And this decision required alternate contingency plans.

After the explosion of the Columbia eight years ago, which killed the seven astronauts on board, the space agency carefully drew up plans for what to do if an orbiter reached space safely but was damaged and could not return. Columbia was damaged during liftoff when a piece of debris struck one of its wings, creating a hole that caused the shuttle to break up on its way back to earth. Investigators subsequently concluded that the problem could have been detected.

For each post-Columbia shuttle trip to the International Space Station, astronauts have inspected the orbiter’s underside for damage to the heat shield similar to the puncture in Columbia’s left wing caused by falling foam. The plan was that if any such damage were found, the astronauts would remain at the space station until the next shuttles arrived and carried them home.

This time, if there were such a problem, it would be the smaller, three-seat Soyuz capsules that brought the astronauts home. Over the following year, the Soyuzes would launch with a crew of two instead of three, and a shuttle astronaut would take the empty seat on the return trip.

An extended stay for seven stranded shuttle astronauts, in addition to the station’s six crew members, would exhaust the station’s food and supplies. But with four unexpected guests, the strain on the station would be manageable. “We’ll be able to, I think, sort of assimilate into space station life fairly straightforwardly, if it would happen,” said Sandra H. Magnus, a member of the Atlantis crew.

All four astronauts — Captain Ferguson; Col. Douglas G. Hurley of the Marines; Dr. Magnus; and Rex J. Walheim, a retired Air Force colonel — are experienced space fliers, and all four will be busy during the 12-day mission, moving 8,000 pounds of supplies and spare parts.

“Having four folks who have done this at least once in the past will add dramatically to our efficiency on orbit,” Captain Ferguson said.

And there may be some advantages to the smaller crew. “There are less opinions to contend with,” Captain Ferguson said, drawing some laughs.

But the last day before landing is expected to be particularly hectic, with the four performing tasks usually divided among six or seven. The Atlantis is to return to Kennedy Space Center on July 20, although NASA could extend the mission by a day.

After the retirement of the shuttles, NASA will be counting on two companies, the Space Exploration Technologies Corporation, of Hawthorne, Calif., and Orbital Sciences, of Dulles, Va., to carry supplies to the space station. The additional Atlantis flight provides a cushion in case of further delays by the companies, keeping the station supplied through next year.

Space Exploration Technologies, or SpaceX for short, successfully launched its Falcon 9 rocket twice last year, but will get at most one off the ground this year. The next flight, a demonstration to show that it can navigate its space capsule to the station, has been delayed from spring to late fall.

Meanwhile, Orbital suffered a setback last month when an engine for its rocket caught fire in testing. Orbital still hopes to launch a demonstration flight this year and begin taking supplies to the station next year.

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