Saturday, July 12, 2008

Catholic University professor pioneers lunar telescope-making method

By Brandy Wilson
Catholic News Service

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

Astrophysicist Peter Chen, along with colleagues Michael Van Steenberg, Ronald Oliversen and Douglas Rabin at NASA's Goddard Space Flight Center, has pioneered a method to create giant telescope mirrors on the moon.

"We can do something really unique here. We can go to the moon and create a large telescope 20 or 50 meters across. This is far out of anything 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 be built on earth.

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

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

After several attempts and a "few gooey messes," they came up with something the consistency of a very hard concrete brick. They later determined that by adding an aluminum coating they also could make a sturdy telescope mirror that could withstand extreme temperature changes on the moon and the rare meteor hit. Currently, there are no working telescopes on the moon.

"People are trying to find interesting ways to (advance) science by going back to the moon, to justify going back to the moon," Frank Reddy, a senior editor at Astronomy magazine, told CNS in a phone interview. Reddy attended a presentation Chen gave to the American Astronomical Society.

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

Despite the low-tech approach, their technique breaks new ground for several reasons. First, it utilizes lunar regolith, or moon dust, as an ingredient. Moon dust is an abundant, local resource on the 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 to outer space. Making the telescope mirrors on the moon would reduce the cost and risks entailed with shipping a giant telescope mirror to the moon. No longer would their size be limited by the size of the rocket.

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

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

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

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

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

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

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

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

But Reddy said, "How practical this is remains to be seen, but it's not crazy."

In addition to his work with NASA, Chen is an adjunct research professor for Catholic University's Institute for Astrophysics and Computational Science. He's a married father of four, with a cat he said thinks it's a dog.

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