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Jeudi, 22 Septembre 2011 00:29

Astronomers Plead for Space Telescope's Life

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Astronomers Plead for Space Telescope's Life

NASA officials and leading astronomers say the James Webb Space Telescope, successor to the Hubble Space Telescope, should still fly despite mounting criticism, cost increases, and disagreements within the astronomy community.

Initially estimated to cost approximately $1 billion in 1996, recent calculations for the telescope peg its price tag at nearly $8.7 billion. An independent panel last year placed the blame for these cost increases on delays and mismanagement by NASA officials. These problems have even created a congressional scuffle, with the House of Representatives voting to zero out the telescope’s budget while the Senate produced a bill to fully fund it. The two are currently trying to reconcile the discrepancy.

The agency has recognized its past mistakes and now “knows that this is our last chance to do this right,” said Rick Howard, JWST program director at the agency, during an online town hall meeting devoted to answering public questions about the telescope on Sept. 21.

The 6.5-meter infrared JWST will have the largest-diameter mirror ever launched into space — three times the size of Hubble’s. It is expected to allow astronomers to look back in time to the earliest period of galaxy formation, help determine the nature of dark matter and energy and observe light from exoplanets around other stars.

Innovative as it may be, the telescope’s budgetary problems have come at a particularly inopportune time when the federal government is looking to slash expenditures.

While NASA officials have said in the past that cost overruns are not expected to affect the agency’s other science projects, the increased price estimates have made it possible that JWST will take as much as 50 percent of its needed funds from NASA’s science division, said Howard.

This has some members of the astronomy field worried. A group of notable planetary scientists, including Alan Stern, the former NASA head and principle investigator of the New Horizons mission to Pluto, posted an open letter on Sept. 8 stating they were concerned that future solar system exploration was under threat from JWST’s cost overruns. One day later, members of the solar physics community sent out a memo expressing similar concerns.

But JWST still deserves the full support of the astronomical community, said Matt Mountain, director of Space Telescope Science Institute (STScI) in Baltimore, Maryland, during the conference. Just like its predecessor Hubble, the telescope is expected to change the way all scientists understand the universe, he added. And at least 6 to 10 percent of Hubble’s time has gone to planetary scientists, he said, who have used it to image spectacular phenomena in our own solar system, such as the impact of comet Shoemaker-Levy 9 with Jupiter.

Other astronomers seconded this support at the meeting. The planetary science community will benefit from JWST, said Jonathan Lunine, a planetary scientist at Cornell University in Ithaca, New York, either through observations in the solar system or with data from extrasolar planets. Lunine suggested that the planetary science community propose observing programs for JWST instead of opposing the telescope.

“When we fight each other, we all tend to lose,” he said.

Given the difficulties, some of the questions during the town hall meeting focused on whether or not to cancel the costly telescope. The panel members reiterated that this is not something they want or expect to happen and said that if JWST were canceled, it would not be available for other projects. NASA would forfeit it entirely.

“There is no doubt that it’s a challenge and we are living in challenging times,” said Roberto Abraham, an astronomer at the University of Toronto in Canada. But, he added, completing JWST would be “seen as a clear message that the U.S. is still capable of doing really great things.”

Image: NASA/MSFC/David Higginbotham


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