NASA plans to study the galaxy through giant telescopes on the moon
07 Jun 2008
Washington: Scientists from the National Aeronautical and Space Agency (Nasa) plan to fabricate the largest telescopes ever on the surface of the Earth's moon, using a mixture of carbon and moon dust.
According to NASA's Peter Chen, the huge telescopes could be made on the moon relatively easily, and would be cheaper than transporting a large mirror from Earth. He says most of the materials are already there in the form of dust, so ''you don't have to bring very much stuff with you, and that saves a ton of money."
Chen had been working with carbon-fibre composite materials for many years, to produce prime telescope mirrors. Later, he substituted carbon nano-tubes, the tubular structures of pure carbon, for carbon-fibre composites. When mixed with small amounts of carbon nanotubes and epoxy, a glue-like material, with crushed rock that had the same composition as lunar dust, it created a very strong concrete-like material, which can be used instead of glass to make mirrors.
Chen says that next they applied additional layers of epoxy, and then spun the material at room temperature, resulting in a 12-inch wide mirror blank with the parabolic shape of a telescope mirror.
"After that, all we needed to do was coat the mirror blank with a small amount of aluminium and voilà, we had a highly reflective telescope mirror," says Chen's fellow scientist at NASA, Douglas Rabin. "Our method could be scaled-up on the moon, using the ubiquitous lunar dust, to create giant telescope mirrors up to 50 meters in diameter."
An observatory of this kind would effectively dwarf the world's largest optical telescope, which is the 10.4-metre Gran Telescopio Canarias located in the Canary Islands.
The capabilities of a 50-meter telescope on the Moon open unimagined possibilities, says NASA.
A stable platform, with no atmosphere to absorb or blur starlight, the lunar telescope could document the spectra of extra solar terrestrial planets, and detect atmospheric biomarkers such as ozone and methane.
Moreover, two or more such telescopes spanning the surface of the Moon can work in tandem to photograph direct images of Earth-like planets around nearby stars, and find brightness variations from oceans and continents. They could also make detailed observations of galaxies at various distances, and provide insights into the evolution of the universe.
"We could also use this on-site composite material to build habitats for the astronauts, and mirrors to collect sunlight for solar-power farms,'' says Chen.
