An astronomical telescope: This artist’s rendering shows a proposed 50-meter telescope that could be built on the moon using NASA’s new approach. To show just how large this is, note the 18-wheeler and two people standing in front of the telescope.
In contrast, NASA scientists used a combination of readily accessible materials: carbon nanotubes, epoxies, and a crushed rock that has the same composition and grain size as lunar dust. The mixture created a very strong material with the consistency of concrete. The scientists then added another layer of epoxy and spun the material to generate a 12-inch-wide mirror with the parabolic shape of a telescope mirror. Although spinning epoxy is unlikely to freeze the mirror into a perfect optical surface, it is easy to adapt standard industrial processes to make telescope mirrors of high quality and smoothness, says Chen. He and his group have also developed a noncontact method called reactive ion etching, which they have shown can modify the epoxy surface at will, remotely.
“Demonstrating this [method] on a 12-inch mirror is just a first small step towards what it would take to build a production facility capable of making a 50-meter telescope,” says Lee Feinberg, a NASA scientist who manages the James Webb telescope.
A major concern regarding equipment constructed on the moon would be keeping high-precision mechanical surfaces (joints, bearings, and so on) from being clogged by dust. There are also large temperature swings between daytime and nighttime that would place high demands on the integrity of the moving mechanical parts.
But first, NASA has to get to the moon, a feat that it hopes to accomplish by 2020.