Solar sail

Recently, Interest has been shown in a solar sail to propel spacecraft through the solar system, using the pressure of sunlight on the sail as the driving force (1, ). A thin reflective metal-coated plastic film was required for the sail which would be stable for long periods of time to the severe temperature and radiation conditions encountered in space. One of the films considered for the solar sail was the polyimide film prepared from pyromellitlc dianhydride and bis-(4-amlnophenyl) ether (, ) 5... 

The desired thickness of the film for the solar sail application was 2.5 ym, but the thinnest commercially available film of this type was Du Font s Kapton O) with a thickness of <7.5 ym. Hence, a need existed to thin the latter film and to assess the photo-and thermal stability of the resulting, thinned film. This paper describes the use of a radiofrequency (RF) oxygen plasma for etching (thinning) of poly[, N-oxydiphenylene) pyromellitimide] (POP) film, and presents data on the photo/thermal degradation of etched and unetched film in vacuum. Although plasma etching has been applied to many polymers, it has scarcely been used on... 

Wright, J., and Warmke, J., "Solar Sail Mission Application," Paper 76-808, AIAA/AAS Astrodynamics Conference, August 1976. 

A California company called HaveBlue sells a power system for sailing yachts with solar panels, a wind generator and a fuel cell. The solar panels provide 400 watts of power for the cabin systems and electrolyzer for producing hydrogen from salt or fresh water. The hydrogen is stored in six tanks in the keel. Up to 17 kilograms of hydrogen is stored in solid matrix metal hydrid. The tanks replace 3,000 pounds of lead ballast. 

Jet Propulsion Laboratory. "Sail Film Materials and Supporting Structures for a Solar Sail" JPL Report 720-9 Pasadena, CA , 1979. 

Mclnnes, C.R., Solar Sailing Technology, Dynamics, and Mission Applications. Springer, Berlin, 2004. 

Sunlight strikes a solar sail on a spacecraft and is converted directly into a force on the sail, which causes motion of the craft. 

Extreme Applications of Barometry. The basic origins of pressure can be used to explain the pressure due to radiation as the momentum flux of photons. At Earth s orbit around the Sun, the solar intensity of 1.38 kilowatts per square meter causes a radiation pressure of roughly 4.56 micropascals. Solar sails have been proposed for long-duration missions in space, driven by this pressure. Close to the center of the Earth, the pressure reaches 3.2 to 3.4 million bars. Inside the Sun, pressure as high as 250 billion bars is expected, while the explosion of a nuclear-fusion weapon may produce a quarter of that. Metallic solid hydrogen is projected to form at pressures of 250,000 to 500,000 bars. 

The field of propulsion deals with the means by which aircraft, missiles, and spacecraft are propelled toward their destinations. Subjects of development include propellers and rotors driven by internal combustion engines or jet engines, rockets powered by solid- or liquid-fueled engines, spacecraft powered by ion engines, solar sails or nuclear reactors, and matter-antimatter engines. Propulsion system metrics include thrust, power, cycle efficiency, propulsion efficiency, specific impulse, and thrust-specific fuel consumption. Advances in this field have enabled hiunanity to travel across the world in a few hours, visit space and the Moon, and send probes to distant planets. 

Solar sails, consisting of large membrane mirrors that would utilize solar radiation pressure, have been proposed for spacecraft propulsion. Unlike rockets, the thrust is small, but because solar sails require no fuel and operate continuously when exposed to sunlight, significant speeds can be achieved when they are deployed in space. 

PI(3,3 /4, 4 -ODPA/4,4 -ODA) was the smallest, as shown in the polyimides from BPDA and E was maintained at 10 Pa at 400°C as a result of crystallization. The E values of PI(2,3,3, 4 -ODPA/ 4,4 -ODA) and PI(2,2,3, 3 -ODPA/4,4 -ODA) decreased drastically at the Tg, and showed high thermoplasticity. PI(2,3,3, 4 -ODPA/ 4,4 -ODA) could be prepared as thin film because of its high thermoplasticity [43, 45]. As the thin film maintained high strength even after molten adhesion, PI(2,3,3, 4 -ODPA/4,4 -ODA) was used with APICAL AH ( Kapton-type polyimide) as the thin film on the Small Solar Power Sail Demonstrator "IKAROS". Wholly aromatic polyimides without aliphatic moietes have electron-beam-resistant and proton-beam-resistant characteristics in space environments. 

One might think also of a solar-driven aircraft The availability of photoactive organic polymers may give rise to photovoltaic "sails" for the collection of solar energy in flight. 

JAXA (Japan Aerospace Exploration Agency) Press release of 23 July 2010, Small Solar Power Sail Demonstrator TKAROS Successful Attitude Control by Liquid Crystal Device. 

Edwards, L., IKAROS unfurls first ever solar sail in space, 11.06.2010 http // www.physorg.eom/newsl95460006.html. 

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