Catholic University professor pioneers lunar telescope-making method

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TELESCOPE Jul-10-2008 (810 words) With photos. xxxn

Catholic University professor pioneers lunar telescope-makingmethod

By Brandy Wilson
Catholic News Service

GREENBELT, Md. (CNS) -- An adjunct professor at The CatholicUniversity of America in Washington has devised a new way to seeouter space -- from the moon.

Astrophysicist Peter Chen, along with colleagues Michael VanSteenberg, Ronald Oliversen and Douglas Rabin at NASA's GoddardSpace Flight Center, has pioneered a method to create gianttelescope mirrors on the moon.

"We can do something really unique here. We can go to the moon andcreate a large telescope 20 or 50 meters across. This is far out ofanything that exists on earth," said Chen in an interview with Catholic News Service July 8 at the space center in Greenbelt, a Washington suburb.

Gravity limits to much smaller diameters how big telescopes can bebuilt on earth.

The new technique uses a combination of a carbon-fiber compositematerial known as carbon nanotubes, simulated moon dust andepoxies. Chen had already been working with carbon-fiber materials.Van Steenberg was working with lunar dust. They wondered what theymight get if they combined the ingredients.

"It came about by accident," Chen said. "We were just playingaround."

After several attempts and a "few gooey messes," they came up withsomething the consistency of a very hard concrete brick. They laterdetermined that by adding an aluminum coating they also could makea sturdy telescope mirror that could withstand extreme temperaturechanges on the moon and the rare meteor hit. Currently, there areno working telescopes on the moon.

"People are trying to find interesting ways to (advance) science bygoing back to the moon, to justify going back to the moon," FrankReddy, a senior editor at Astronomy magazine, told CNS in a phoneinterview. Reddy attended a presentation Chen gave to the AmericanAstronomical Society.

The testing equipment for Chen and his colleagues' research wasfairly low-tech. That first successful prototype was formed usingthe bottom of a foam cup as a mold. Chen spun subsequent prototypeson a pottery wheel to get the mirror's parabolic shape. Test modelswere hardened in cake pans.

Despite the low-tech approach, their technique breaks new groundfor several reasons. First, it utilizes lunar regolith, or moondust, as an ingredient. Moon dust is an abundant, local resource onthe moon for which scientists until now haven't found much use.Second, the mirrors will be manufactured on the moon.

Until now, telescopes have been produced on earth and shipped toouter space. Making the telescope mirrors on the moon would reducethe cost and risks entailed with shipping a giant telescope mirrorto the moon. No longer would their size be limited by the size ofthe rocket.

Rabin, chief of NASA's Solar Physics Laboratory, said, "You havepeople thinking about a new way to do things. Ordinary ways ofputting telescopes on the moon, scientists have not found thatattractive. But when you say 20 meters, everything changes. It's aninnovative way of thinking."

The method Chen and his colleagues developed is new, but he hasworked on producing lightweight telescope mirrors for more than adecade and has worked on several space missions.

"I've always enjoyed looking at the stars and wondered what was outthere," he said.

Chen's work could make it easier to find out. By comparison, thelargest telescope in space, the Hubble Space Telescope, has adiameter of 2.4 meters. Chen's method could produce mirrors thatstart at 20 to 50 meters in diameter. Larger mirrors reflect morelight, thus offering finer detail. A 50-meter telescope couldreasonably detect signs of life in a planetary atmosphere.

The bricklike material could also be used to create housingstructures on the moon as well as solar collectors. "The wholepremise of building structures on the moon is something NASA's beenconcerned with for a very long time," Van Steenberg said.

The method is still in development and because NASA won't bereturning to the moon for at least another 10 years, it'll beawhile before it can be field-tested on the moon.

But Chen's work is not without its critics. Larry Taylor, directorof the Planetary Geosciences Institute at the University ofTennessee, Knoxville, is skeptical.

"It's pie in the sky," he told CNS in a phone interview. "Theshowstopper is the amount of material you have to bring from theearth. I think it is a way of making mirrors, but there are otherways you can do it that are more efficient."

But Reddy said, "How practical this is remains to be seen, but it'snot crazy."

In addition to his work with NASA, Chen is an adjunct researchprofessor for Catholic University's Institute for Astrophysics andComputational Science. He's a married father of four, with a cat hesaid thinks it's a dog.

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