MARY LOUISE KELLY, host:
Now, longevity takes on a whole new meaning when we're talking about the stars. And now NASA has a flying telescope, so powerful it's expected to record the birth of distant stars and planets. The telescope, which weighs 17 tons, is built into a 747 that serves as an airborne observatory. It's called SOFIA and it's a marvel of astronomy and aeronautics. But as NPR's Jon Hamilton reports, SOFIA almost didn't get off the ground.
JON HAMILTON: Most telescopes are either fixed to the earth or stuck in orbit, like the Hubble space telescope. The one aboard SOFIA operates somewhere in between - at about 40,000 feet. It does this by peering out through a car-sized hole in the fuselage of 747 as the plane flies through the stratosphere.
Scientists think this novel approach to astronomy will help them to answer some cosmic questions. Eric Becklin, from UCLA, is the project's chief science advisor. He says scientists already know that stars and planets begin as scattered particles in space.
Professor ERIC BECKLIN (UCLA): What we don't know, is when do stars like the sun form? Do they form just out all by themselves and then an earth forms out there, or do they form in clusters? These are the kind of answers that we want to get to. But to do that, we have to go to the very earliest time that stars are forming. And that's what SOFIA can do.
HAMILTON: SOFIA sees these infant stars by detecting infrared radiation, heat rather than visible light. Infrared telescopes don't work very well on the ground because moisture in the atmosphere absorbs the radiation.
But Becklin says at 40,000 feet, there is almost no moisture left.
Prof. BECKLIN: We can actually fly up to a region where it really clears up. So it's kind of like being a cloudy day down here, and all of a sudden it's clear. And you can do that with an airplane. And that's why SOFIA is so special.
HAMILTON: Of course, infrared telescopes in space stay above all the moisture. But they have short lives and can't be tweaked or fixed once they're in orbit. SOFIA is designed to fly for 20 years, and it can be modified after every flight.
That's got scientists pretty excited. But just four years ago, Becklin says, the project almost died.
Prof. BECKLIN: The telescope had been integrated, but we hadn't flown yet. And then all of a sudden, NASA said we're going to cancel SOFIA.
HAMILTON: To understand why SOFIA's future was in doubt, you have to go back to its start 14 years ago. Bob Meyer is the program's manager at Dryden Flight Research Center near Palmdale, California. Meyer says SOFIA always had doubters. Early on, he says, people tended to ask him the same question...
Mr. BOB MEYER (Director, Dryden Flight Research Center): Who would've thought of cutting this big a hole in the back of an airplane? And, you know, my response was, NASA takes on challenges like this and takes what appear to other people to be crazy ideas in turns them into reality.
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HAMILTON: The first step was picking a plane. Meyer says this 747, once part of the old Pan Am fleet, was an obvious choice.
Mr. MEYER: At the time, the 747 was the largest airplane flying. And the telescope was engineered to be as large as it could be and still fit inside a 747.
HAMILTON: That turned out to be more than eight feet across. The plane ended up looking like it had swallowed something very large. There's a noticeable bulge behind the wing. Part of that bulge is a garage-sized door that retracts to give the telescope's mirrors direct access to the night sky. Meyer says the observatory can fly like this for hours.
Mr. MEYER: We're looking at light that was generated, you know, literally hundreds of millions of years ago. So in order to get enough light, it may take hour of just looking at that target to gather enough light from it to reconstruct the picture.
HAMILTON: Skeptics also asked whether a 747 with a big hole in it would fly smoothly enough for cutting-edge astronomy.
Troy Asher, a research test pilot for NASA, remembers the first time they opened the door in flight.
Mr. TROY ASHER (Research Test Pilot, NASA): Sitting there waiting, and they say, okay, we're going to open the door. And there's a countdown: three, two, one, open. And if you didn't actually pay attention extremely carefully when they say ready, ready now, you would've missed it.
HAMILTON: Great engineering. But it all took a lot longer and cost a lot more than it was supposed to, which is why after a decade of overruns, NASA was ready to cancel the program.
Scientists and the German Aerospace Center, a partner in the project, got the decision reversed. But the reprieve came with huge pressure to finish quickly. So it was a big deal when, a few weeks ago, SOFIA took off and opened its telescope to the skies for the first time.
Eric Becklin says the results were better than anyone had expected.
Prof. BECKLIN: We had images that are the sharpest images that have ever been seen of Jupiter and M82, which is a galaxy, a nearby galaxy where massive stars are forming.
HAMILTON: Becklin says now, SOFIA can turn its gaze to distant galaxies, where future stars are still just particles scattered in space.
Jon Hamilton, NPR News.
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