September 19, 2008

Space flux telescope without upper size limit

Here is a diagram for a many small mirror modules that held in position for a space telescope using magnetic flux pinning is 200 meters in diameter.

The phenomenon of magnetic flux pinning might provide a way to connect the telescope components that overcomes the limitations of formation flight or a mechanical support structure. A type of interaction between a magnet and a type II superconductor, flux pinning is analogous to a damped spring force that acts over a distance. A simple model is that of a magnet and a superconductor connected by a virtual spring and damper. This interaction is passively stable and requires only the power needed to keep the superconductor cooled below a critical temperature.

Other Ways to Make Space Telescopes
The limited capacity of a launch vehicle places an upper bound on the size of monolithic telescopes that can be assembled on the ground and sent into orbit. To maximize the size of a monolithic telescope that can be launched, several ingenious strategies have been developed. These strategies include designing inflatable structures and using creative folding techniques to minimize the volume of the telescope. The 6.6m primary mirror of the James Webb Space Telescope, for example,
is designed to fold compactly to allow the telescope to fit into a 5m shroud.

-Origami-like folding technique allows a 25m lens to fit inside current launch
vehicles, the telescope has a focal length of approximately 1 km, necessitating the use of two spacecraft: one for the lens and one for the detector.

-A primary mirror diameter of over 40m in a monolithic telescope is needed for directly imaging earth size planets in other solar systems.

There are several potential advantages to the flux telescope design.

First and foremost, the design is scalable. Although the initial radius of the telescope is determined by the number of mirror segments that are launched, the radius can grow if additional mirror segments are added later. As a result, the aperture of the telescope can be increased gradually, spreading the cost over time. The reconfigurable nature of the flux-pinning interfaces offers another advantage: unlike the Hubble Space Telescope, which required an expensive manned mission to repair a defective mirror, a telescope whose mirror segments were flux-pinned could be repaired autonomously. Misplaced or imperfectly deformed mirror segments can be repositioned or reoriented remotely, and since the mirror segments are interchangeable, removing and replacing any damaged or destroyed segments can require minimal human involvement. In addition, since flux pinning requires no active control, the telescope is passively stable in the event of a software-related failure and able to maintain its shape using only the minimal amount of power required to cool the superconductors. One final advantage of this design stems from its overall geometry. As a spherical shell of mirror segments with a detector floating at the center, the telescope is roughly isotropic, so it can be repointed by rotating the central detector and deforming the mirror segments appropriately. If the mirrors are capable of deforming sufficiently quickly, then this telescope could repoint in less time [shapeshifting like a liquid Terminator to point in a new direction] than an equivalently sized telescope requires to slew, lending the telescope high agility.

blog comments powered by Disqus