Flying telescope makes heavenly visit

Long-awaited--and long-delayed--airborne observatory called Sofia makes first trip to NASA Ames, which had been expected to be its home. Photos: Flying observatory's homecoming

MOUNTAIN VIEW, Calif.--Visiting the world's largest flying telescopic research lab here Monday, I got a flash of the 1970s film Heaven Can Wait.

Not so much for the content of the movie, which starred Warren Beatty, but more for its title. The plane, called Sofia (for "stratospheric observatory for infrared astronomy"), is being built so that scientists can study celestial bodies more accurately with a powerhouse infrared telescope, yet it's been 12 years in the making--delayed at least six years--and still isn't off the ground.

Also, much as in the film, in which actors slowly board a jumbo jet toward their "final destination," employees here at NASA Ames Research Center were awed to finally see in person a project they've worked on for years. At its start in 1996, Sofia was expected to be stationed at Ames, whose lab has worked on scientific instrumentation for the plane, among other things. But Sofia is now housed at NASA Dryden in Southern California, and Monday was the plane's first visit.

To illustrate the disbelief, one NASA Ames employee on a tour of the plane said co-workers jokingly replace the line "When pigs fly"--meant to convey a sense of impossibility--with "When Sofia gets here."

Jokes aside, the day was exciting for everyone involved--especially Sofia's lead scientists. They expect to see the airborne observatory finally conduct scientific missions as early as April 2009, after the completion of further test flights. The project is expected to be funded for 20 years, at an estimated total cost of $1.7 billion, according to a NASA representative.

Sofia is a former Pan-Am 747 SP (special performance) passenger plane, one of only 45 made and formerly named the Clipper Lindbergh, after aviation pioneer Charles Lindbergh. It was before NASA took it over to replace its predecessor, the Kuiper Airborne Observatory, a C-141 cargo jet that operated from 1975 to 1996. (The Kuiper carried a 36-inch telescope.)

In 2001, NASA gutted Sofia and cut a 16-foot hole through its exterior to eventually place inside a 2.5-meter infrared telescope, which was built by a German company. (Germany is a partner with the United States on Sofia.) Today, the mirrored telescope is securely inside, pressurized, and protected in part by an external electronic door on the plane, which can open and track the angle of the telescope while flying. That way, the telescope always has a clear shot of its subject matter.

The delicacy of the design, however, demands testing. Last year, NASA completed successful flights of the plane with its door closed. And this fall, it plans to evaluate flight with the electronic door open--a crucial test to see whether the telescope can withstand vibration while airborne.

Last year, Sofia was rededicated as the Clipper Lindbergh by Erik Lindbergh, the grandson of Charles Lindbergh.

Sofia carries the largest airborne infrared telescope, which measures 2.5 meters in diameter. With Sofia flying at an altitude of 45,000 feet, above 99 percent of the Earth's water vapor that blocks infrared heat, the telescope will be able to detect most of the infrared radiation reaching Earth from celestial objects, according to NASA. That way, scientists can study regions obstructed by dust, older stars, or other colder materials.

It's a more efficient way of studying the cosmos, NASA says, because technicians can replace instrumentation in the plane like they would with a ground-based telescope, without the expense of a space telescope like the Hubble.

According to Sofia's chief scientist, Eric Becklin, the team plans for its first scientific mission to look at a massive black hole in the Milky Way--the closest black hole to Earth.

"We'll have a clearer view of it than ever before," Becklin said.

Foreshadowing the heavenly mission, he said: "This is a major observatory that's unique in the world. It's going to make new discoveries."

I guess we'll have to wait.

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