"Lunar Concrete" May Form Buildings on the Moon

Ker Than
for National Geographic News
June 4, 2008
A new type of "lunar concrete," made by mixing moondust and carbon nanotubes, could be used to construct buildings, solar power arrays, and monolithic telescopes on the moon.

"We could make huge telescopes on the moon relatively easily and avoid the large expense of transporting a large mirror from Earth," said Peter Chen of NASA Goddard Space Flight Center and the Catholic University of America.

Astronauts would only need to bring aluminum to coat the surface of the telescope.

"Since most of the materials are already there in the form of dust, you don't have to bring very much stuff with you—and that saves a ton of money."

(Related: "Moon Base Announced by NASA" [December 4, 2006].)

The new technique was described today at a meeting of the American Astronomical Society in St. Louis.

Smelly Goo

Chen and his colleagues were working on ways of using carbon-fiber composites to create lightweight telescopes easily transportable to the moon when they decided to substitute the carbon fiber with carbon nanotubes—tiny tubes made of pure carbon.

The team wondered what would happen if they mixed carbon nanotubes with gluelike materials called epoxies and simulated moondust supplied by NASA.

"We went to the lab, whipped up a batch of this stuff, and presto, we ended up with something very gooey and very smelly," he said.

After some more tinkering, the team ended up with a very strong material that had the consistency of concrete.

Looking for ways to put the material to good use, the team applied additional layers of epoxy to their lunar concrete as it was spinning.

The result was a 12-inch-wide (30-centimer-wide) bowl-shaped object that could be coated with aluminum and transformed into a mirror.

The mirror could be used to create solar arrays that collect sunlight on the moon or enormous telescopes unlike anything seen on Earth.

"Our method could be scaled up on the moon, using the ubiquitous lunar dust, to create giant telescope mirrors up to 50 meters [164 feet] in diameter," Chen said.

(See photos of past missions to the moon.)

Ideal Site

Such an observatory would dwarf the 34-foot (10.4-meter) Gran Telescopio Canarias in the Canary Islands, currently the largest optical telescope in the world.

"The moon is generally considered the best site in space for astronomy because it combines the best quality of space, which is vacuum, and the ground, which is a stable platform," Chen said.

With no atmosphere to absorb or blur sunlight, a colossal lunar telescope could gather light from distant exoplanets or detect traces of life in their atmospheres.

(Related: "New Alien-Life Search Aims to Eavesdrop on ETs" [January 11, 2007].)

Two or more such telescopes working together could directly image Earthlike planets around nearby stars.

"But why stop there?" Chen asked. "If we know how to smooth the dusty surface on the moon and make it shiny, why don't we just go ahead and do a whole crater …? We can actually go and 'mirrorize' a whole crater."

Yu Qiao is a materials scientist at the University of California, San Diego, who has also worked on lunar infrastructure materials but was not involved in Chen's study.

He called the new technique "very promising" but said the material will have to pass long-term durability tests.

"Many epoxies may be fragile after a few years of exposure to radiation, and radiation at the lunar surface is very intense," he said.

Qiao also noted that some materials more lightweight than epoxy might also be suitable for the task.

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