2012年2月19日 星期日

Revolutionary design, runaway costs

In deep, cold space, nearly a million miles from Earth, a giant telescope later this decade will scan for the first light to streak across the universe more than 13 billion years ago.

The seven-ton spacecraft, one of the most ambitious and costly science projects in U.S. history, is under construction for NASA at Northrop Grumman Corp.'s space park complex in Redondo Beach.

The aim is to capture the oldest light, taking cosmologists to the time after the big bang when matter had cooled just enough to start forming the first blazing stars in what had been empty darkness. Astronomers have long dreamed about peering into that provenance.

"It is the actual formation of the universe," said Alan Dressler, the astronomer at the Observatories of the Carnegie Institution for Science in Pasadena who chaired a committee that proposed the telescope more than a decade ago.

If the James Webb Space Telescope works as planned, it will be vastly more capable than any of the dozen currently deployed U.S. space telescopes and will be a dramatic symbol of U.S. technological might. But for all its sophistication, the project also reveals a deeply ingrained dysfunction in the agency's business practices, critics say. The Webb's cost has soared to $8.8 billion, more than four times the original aerospace industry estimates, which nearly led Congress to kill the program last year.

The agency has repeatedly proposed such technologically difficult projects at bargain-basement prices, a practice blamed either on errors in its culture or a political strategy. Rep. Frank R. Wolf (R-Va.), chairman of the House appropriations subcommittee that controls NASA's budget, said a combination of both problems affected the Webb.

"There was not adequate oversight," Wolf said. "And there were reports that the cost estimates were being cooked a little bit, some by the company, some by NASA."

It could spell a new era for the space agency, in which it will have money for just one flagship science mission per decade rather than one every few years as it has in the past. The Webb's cost growth, along with an austere budget outlook for NASA, is depleting the agency's pipeline of big science missions. A much-discussed mission to return samples of Martian soil to Earth, for example, may be unaffordable, according to the House Science Committee staff.

The Webb telescope was conceived by the astronomy community in the late 1990s as a more modest project with a smaller mirror for about $500 million. Then-NASA chief Daniel Goldin challenged the science community in a major speech to double the capability of the telescope for the same price.

Dressler, who was in the audience when Goldin gave the speech, recalled: "It astonished everybody. It made no sense that you could build a telescope six times larger than Hubble … and have it come in cheaper. We were so stunned, we didn't know what to do."

The early lowball cost figures had no official standing, but they shaped political expectations many years later.

沒有留言:

張貼留言