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December 10, 2006

Near term solar sails

Centauri dreams has a couple of interesting articles about near term solar sails. Gregory Benford (University of California at Irvine) and his brother James (Microwave Sciences) have solar sail with a painted polymer layer that desorp from the sail as extra propulsion

The solar sail could be deployed in low Earth orbit by conventional rocket. It would then be launched by microwave beam, the heat of which would cause a polymer layer to desorp from the sail (think of desorption as the opposite of absorption — some of the ‘paint’ material is released to provide propulsion).

The microwave beaming cancels most of the sail’s orbital velocity around the Sun, causing it to fall toward it. The craft approaches edge-on but at perihelion, a few solar radii out, it rotates to face the Sun. Now a second layer of polymers desorps away under the intense sunlight, and the craft gets a 50 kilometer per second boost, departing the area as a conventional reflecting solar sail with its final layer of aluminum now exposed. Mission speed is approximately 10 AU per year. A parting boost from a microwave transmitter in Earth orbit could add still more delta-V.


New Scientist also covered this solar sail with painted on propulsion fuel

Wikipedia covers solar sails In 2000, Energy Science Laboratories developed a new carbon fiber material which might be useful for solar sails.[5] The material is over 200 times thicker than conventional solar sail designs, but it is so porous that it has the same weight. The rigidity and durability of this material could make solar sails that are significantly better than plastic films. The material could self-deploy and should withstand higher temperatures. Energy Science Laboratories' new carbon fiber material weighs in at 3g/m2.

There is another article about near term solar sails

Magnetically inflation could be used to expand 1 kilometer or larger solar sails



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