美国国家公共电台 NPR As NASA Aims For The Moon, An Aging Space Station Faces An Uncertain Future（在线收听）

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NASA and its partners spent years and more than $100 billion to build the International Space Station. That was more than two decades ago. Now they have to figure out what to do with it next. NPR's Nell Greenfieldboyce reports.

NELL GREENFIELDBOYCE, BYLINE: In November of 1998, NPR reported that a rocket had blasted off from Kazakhstan.

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UNIDENTIFIED REPORTER: Onboard was a 20-ton module, the first part of the International Space Station. Once completed, the space station will serve as an orbiting home for astronauts and cosmonauts for at least 15 years.

GREENFIELDBOYCE: It's now been over 18 years that the station has been continuously occupied by people. The place is impressive, with more living space than a six-bedroom house, two bathrooms and a large bay window for looking down at Earth. It's also really expensive. NASA spends between $3- and $4 billion a year operating the station and flying people back and forth. That's about half the agency's budget for human exploration of space and a real financial drag when NASA is gung-ho to return to the moon. So maybe all the international partners could just say, the station's day is done. Let's deorbit it, crash it in the ocean and move on to the next thing. I put that idea to Gilles LeClerc. He's head of space exploration at the Canadian Space Agency.

GILLES LECLERC: It would be a waste. We cannot ditch the International Space Station. There's just too much invested. It's quite clear. It's unanimous between the partners that we continue to need a space station in the Earth's orbit.

GREENFIELDBOYCE: The U.S. and the other nations have pledged to fund the station until at least 2024. What happens after that is unclear. But NASA has floated one idea - turn all this over to the private sector.

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JEFF DEWIT: Today's a very remarkable day. NASA is opening the International Space Station to commercial opportunities and marketing these opportunities as we've never done before.

GREENFIELDBOYCE: That's NASA's Chief Financial Officer Jeff DeWit. He was speaking at a big press event held a few weeks ago at the Nasdaq stock market's market site in New York City. He was joined by other officials and even astronaut Christina Koch, who appeared in video beamed down from space.

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CHRISTINA KOCH: We are so excited to be part of NASA as our home and laboratory in space, transitions into being accessible to expanded commercial and marketing opportunities as well as to private astronauts.

GREENFIELDBOYCE: All this gave John Logsdon deja vu. He's a space historian with George Washington University. He says back in the 1980s, when Ronald Reagan's administration first proposed building a permanent space station, this was part of the pitch.

JOHN LOGSDON: The idea that it could be a place for a wide variety of commercial activities with billions of dollars of economic payoff - so here we are in 2019 finally going to test that hypothesis.

GREENFIELDBOYCE: NASA officials said opening up the station to profit making activities would free up resources to go to the moon. But when reporters asked how much revenue could come in, NASA officials wouldn't give any numbers. They said there's too much uncertainty.

TOMMY SANFORD: That is the right answer because they don't know yet.

GREENFIELDBOYCE: Tommy Sandford is executive director of the Commercial Spaceflight Federation. He says NASA's goal is to have a station that's commercially operated or even privately owned, and NASA would become just one of many customers.

SANFORD: You need to be focused on adding as many customers as possible and hoping to reach a tipping point at some point where you retain all of them. And then that eventually lowers your costs because, again, you are one of many customers. You're not bearing the entire cost of the infrastructure and the transportation.

GREENFIELDBOYCE: But some question whether any business could make a go of it unless NASA still ponied up a significant amount of money. The agency's Inspector General Paul Martin testified at a congressional hearing last year about the space station's future.

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PAUL MARTIN: Candidly, the scant commercial interests shown in the station over its nearly 20 years of operation give us pause about the agency's current plans.

GREENFIELDBOYCE: As all of these discussions go on, the station keeps getting older. Space is a harsh environment. The hardware is wearing out. Major components are only certified until 2028. Dava Newman is a scientist at MIT who used to be the deputy administrator of NASA.

DAVA NEWMAN: Space station really has up to, you know, say, less than 10 years of lifetime for it to be safe and in terms of to not have too high of maintenance costs.

GREENFIELDBOYCE: She loves the station, has flown experiments on it. But she thinks with time running out, a strategic plan for its end is needed now.

NEWMAN: There might be some elements of space station that the private sector might be able to take over - a module or two. So all that needs to be put in place, probably with government funding.

GREENFIELDBOYCE: Eventually, big components of the station will have to crash back down towards Earth. I asked NASA when it expected to deorbit the station. A spokesperson said no specific year is being targeted, that NASA will transition from the station, quote, "once commercial habitable destinations are available."

Nell Greenfieldboyce, NPR News.

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