07-23-2009 - Space

The recent 40th anniversary of the first lunar landing reminded me of a conversation I had a year ago with Peter Chen of the NASA Goddard Space Flight Center and the Catholic University of America, which is located in Washington, D.C.

He said then that moon fever is staying alive with hopes of turning lunar dust into concrete, and even mirrors for a possible 50-meter telescope 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,” he said.

Chen and his colleagues used crushed rock with similar composition and grain size to what’s abundant on the surface of the moon, and they mixed in cryogenic glue-like epoxies and carbon nanotubes for thermal stability to withstand the harsh temperature changes found on the moon.

“We made several tries in the laboratory,” said Chen to EarthSky, “and interestingly enough we found something that is very hard. It has the consistency of concrete, and it’s quite stable in the sense that we can heat it, and we drop it in liquid nitrogen and it comes out fine.”

Chen added, “so we said, hey, that makes a very good stable structure. Maybe we can use it in place of glass to make a telescope on the moon.” That’s done by topping a slab of the lunar concrete off with additional layers of epoxy and spinning the material to the smoothness needed for mirrors at room temperature.

Chen said that the moon is considered by many scientists as the best site for an astronomical observatory, mainly because of the clarity of images obtained from space in the absence of an atmosphere and the stable platform of the lunar surface compared to moving space-based observatories.

“And this is especially true of the project for looking for other planets like Earth,” said Chen.

Chen used the analogy that attempting to look for an Earth-like planet around another star at 30 parsecs is equivalent to “looking for a speck of dust 100 micrometers across in Los Angeles, looking from New York.”

“So you can see,” he added, “to resolve the object, you need a large area to collect the photons, and secondly you have to be extremely stable in your pointing. And the moon can let you do that.”

What’s more, Chen speculated on the enormous potential for mirror-building material, with the possibility of coating entire craters with telescopic mirrors, and in a sense, turning the moon into what might appear to be an enormous disco ball.

“You can actually daydream about putting a giant, shiny spot on the moon, or actually make the moon into a whole giant mirror ball with this technique, Chen said. “This kind of thing is what makes science fun, and that it is not actually that far-fetched.”

NASA plans a manned mission to the moon by 2020 as a precursor to missions to Mars, and the lunar concrete could also be used for housing and other structures needed for a long-term lunar base.

Written by Jorge Salazar