私营公司将承担美国载人航天任务

MICHELE NORRIS, host: This day, 25 years ago, brought a moment of reckoning for NASA. When the Challenger exploded, it was the first time the U.S. had ever lost astronauts during a flight. Now, NASA finds itself at another crossroads: Astronauts may soon be flying not on a shuttle but on private spaceships.

So, what might happen if a commercial space company had an accident on the scale of a Challenger?

NPR's Nell Greenfieldboyce reports.

NELL GREENFIELDBOYCE: Twenty-five years ago today, space shuttle Challenger lifted off into the Florida sky.

Mr. RICHARD COVEY: Challenger, go at throttle up.

Mr. FRANCIS RICHARD SCOBEE: Roger, go at throttle up（加油门）.

GREENFIELDBOYCE: Suddenly, a nightmare - a huge cloud of smoke. The path of the spaceship cut short. Ed Mango remembers that day. He was an engineer in NASA's Launch Control Center. And later, in 2003, NASA assigned him to recover what was left of space shuttle Columbia when it broke up during reentry. He and his colleagues at NASA don't need an anniversary to remind them of those dark days.

Mr. ED MANGO (Director, Constellation Space Transportation Planning Office, NASA Kennedy Space Center): Challenger and Columbia are very much part of what we think about this week, if not every week.

GREENFIELDBOYCE: Mango now spends his work week planning for a future without the space shuttles. NASA will stop flying them later this year. And Mango heads the Space Transportation Planning Office at Kennedy Space Center. He says, by around 2015, it's possible that astronauts could be riding on the outer space version of rental cars. Spaceships owned, designed and built not by NASA but by private companies. Mango says his number one priority is to make sure those flights are safe.

Mr. MANGO: The responsibility for the mission is still ultimately accountable to NASA. And if the vehicle does not fly right, then we will be held accountable for what has happened.

GREENFIELDBOYCE: The agency has been preparing a list of safety standards that a private spaceship will have to meet before any NASA astronaut climbs on board. Some space industry watchers have criticized a draft of these standards as being too burdensome. Before, astronaut Ken Bowersox says, his company is just glad to finally get them.

Bowersox works for SpaceX. An unmanned test version of its capsule（太空舱） has already launched, orbited Earth and returned as planned. After a number of successful missions carrying cargo, people could be next. Bowersox says, just because the SpaceX rocket ship is designed to be cheap, that doesn't mean it won't be safe.

Mr. KEN BOWERSOX (Vice President, Astronaut Safety and Mission Assurance Department, SpaceX): Let's look at a Ferrari and a Honda Civic or a Toyota Yaris. They're greatly different in cost, but would you say that the little economy cars are less safe or more safe than the Ferrari?

GREENFIELDBOYCE: Still, any accident would probably result in a long investigation and spaceflights being grounded. Could a private company survive that?

Mr. BOWERSOX: A lot depends on how the private company reacts, and a lot of it depends on the root cause of the failure. But you can imagine that any company in that situation would have a lot of pressure on it.

GREENFIELDBOYCE: It's unclear how the public would feel about a major disaster with a private spaceship. John Logsdon is a space policy expert with George Washington University. He says, if an accident occurred during some of the first commercial spaceflights, it might create doubt about whether private companies can really manage the risks of human spaceflight.

Mr. JOHN LOGSDON (Space Policy Expert, George Washington University): But if it's three years into a regular service, I think it would be not exactly ho hum（枯燥无味的，厌烦的）, but more akin to an aircraft accident than a space accident.

GREENFIELDBOYCE: After all, these private space companies wouldn't be boldly exploring a new frontier as NASA used to. They'd just be providing a kind of commuter flight to the space station.

Nell Greenfieldboyce, NPR News.