![]() ![]() That's all the more true because while the Hubble zips along just 300 miles (483 km) above the earth's surface, the Webb will sit closer to a million miles (1.6 million km) away, at a spot known as Lagrange Point 2, or L2. "Deploy, shake, deploy," says Willoughby. "We'll deploy each component several times as we assemble," says Willoughby, "and then the entire observatory will be stowed and deployed." It will also be shaken to simulate the rigors of launch, in a chamber originally built to test the Apollo spacecraft. ![]() So the entire assembly telescope, mirrors, sunshade and scientific instruments will be unfolded on the ground for testing, and that will happen more than once. Given that it's even bigger than the telescope itself, the sunshade will have to unfold in space as well. The shield, which always stays between the Webb on one side and the sun, moon and earth on the other, is made of five layers, separated by a bit of empty space for extra cooling. To accomplish that, the Webb will sit atop a sunshield, about the size of a tennis court. It isn't, anyway, if the telescope can be shielded from the heat of the sun and even from the faint heat given off by the earth. To detect the faint glow of infrared, a telescope works best if it's as cold as possible, so that heat from the telescope itself doesn't contaminate the signal. Astronomers have learned that many of the biggest unanswered questions of their field How and when did the very first stars appear? How were the galaxies assembled from those stars? How do planets form? Does the chemistry of distant planets' atmospheres suggest the existence of life? are best answered by looking in infrared, not visible light. (See TIME's graphics "The World's Largest Radio Telescope.")įor the Webb, cold isn't just an obstacle: it's a necessity if the telescope is going to work. That test is a critical one since engineers need to know the material can survive the frigid conditions in deep space. Back in December, the gold was applied, and the mirrors were being readied for testing in a cryogenic test chamber at the Marshall Space Flight Center in Huntsville, Ala. Instead, the mirrors, made of beryllium metal with a microscopically thin coating of gold, will unfurl in space like flower petals to reach their full size. That's because no rocket exists that can hold something so wide. The most significant of these milestones, says Willoughby: "We've completed and that's a big word all 18 segments of the primary mirror, which have been in production for seven or eight years now." Unlike the Hubble's big light-gathering mirror, the Webb's can't be made in one piece. ![]() "In terms of the things we said we'd accomplish by now," he says, "we're on track, and in some areas, we're actually ahead of schedule." Congress ended up funding the Webb after all, and in a telephone call the other day, Scott Willoughby, the Webb program manager at Northrop Grumman (the contractor that's building the telescope for NASA), reported that the slow, meticulous process of building the most powerful stargazing instrument in history is moving steadily ahead. (See photos of West Virginia's Green Bank Radio Telescope.)įortunately for science, though, the rumors of the project's death were greatly exaggerated. bean counters concluded that nothing would become the Webb project quite as much as the end of it. (8 m) across, with more than 17 times the light-gathering power of the Hubble, the Webb was going to cost no more than $500 million and launch by 2007 cross NASA's heart and hope to die! No one really bought that, but no one really expected the budget to swell to $2.6 billion and then to $6.2 billion, or the launch date to slip to 2015 and then 2018 either. Hard on the heels of a report blasting the Webb project for being badly behind schedule and over budget, a House committee voted to axe the partially completed telescope entirely.Įven a space nut could appreciate where they were coming from: originally envisioned in the 1990s as a monster scope 26 ft. Follow last we heard about the James Webb Space Telescope, the souped-up, long-planned successor to the Hubble, the news was not good. ![]()
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