Saturday, December 5, 2009
For the longest time, I have been wondering if a refracting telescope could be used in space, or perhaps even built there. On earth, refractors have not been built past 40 inches (or about 1 meter), because the weight of the glass causes sagging and lens deformation. In space, not only would this not be a problem, but also the lens could be made very thin as it would not need to support any weight. And similarly, the very long focal length could be accommodated with a light weight truss system, tethers, or perhaps nothing at all.
There is also the possible use of Fresnel type lenses, or perhaps even electronic lenses. In any event, this is a project that is considering a 100 meter space telescope. Such a telescope would greatly enhance our understanding of The Universe. It could directly image the surfaces of planets around other stars, probably even showing surface details. It would be a life finder. We would be able to clearly image the most distant galaxies, such as those in the Hubble deep field, and let us clearly see how they have evolved over time. A telescope like this could also probably view solar system objects with as much detail as orbiters. I suspect it could image the surface of Pluto with as good a resolution as New Horizons, but I have not done any math to confirm that.
It sounds impossible now, but a gossamer spacecraft and lens system could potentially be built to 1KM diameter some day. Because almost all of the observable universe is totally out of reach to our probes, we can only look at these things. Light is the key to all astronomy, and telescopes are the light collectors. The bigger the collector, the better. After the incredible work done by the Hubble, space will be exposed to ever larger generations of space telescopes. The James Webb will be next, and it alone will probably blow all previous observations out of the water. When the Ares V comes out, there are plans for monolithic 8m telescopes, and folding telescopes to 16 meters. These will compliment land based telescopes that will approach 50 meters. Decades later, perhaps a space telescopes will pass 50 meters, and then decades later 100 meters.
PDF from the source