GETTING a telescope into orbit is challenging and costly. Astronomers want instruments with the biggest mirrors possible. Big mirrors gather more light, so can see fainter objects. They also have higher magnification, so can resolve finer details. There is a limit, though, to the size and weight of mirror that can be lifted into space on a rocket.
Size can be dealt with by clever design—for example, making a mirror out of hexagonal petals that fold up on top of one another for launch. This is the approach being taken for the forthcoming James Webb space telescope. Weight, though, will always be a problem. What is needed is a radical rethink about what mirrors are made from. And Marco Quadrelli of the Jet Propulsion Laboratory, in Pasadena, California, and Grover Swartzlander of the Rochester Institute of Technology, in New York state, have now provided one.
Their idea is to launch a rocket full of tiny, reflective particles, jettison said particles and then sculpt the resulting cloud of glitter into the shape of a telescope mirror, using laser beams. The lasers would sit on board satellites in orbit close to the cloud.
Shining a laser at something exerts two forces on it. One is in the direction that the beam is travelling, and tends to push the object struck away from the beam’s source. This is known as the scatter force...
from The Economist: Science and technology http://ift.tt/1FRGs75
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