Laser and the Space Elevator: an Approachment
- Paper number
IAC-07-D4.1.06
- Author
Mrs. Elisenda Bou, Universitat Politecnica de Catalunya, Spain
- Year
2007
- Abstract
Some previous experience as a competer in the Space Elevator Challenge, one of NASA X-Prize inspired Centennial Challenges made me realize that higher level on demands in the Elevator Challenge (most because of the higher height teams are expected to arrive to), made teams decline for laser beam-powered designs and discard the Xenon-Focus lights designs of last year competition. Laser beam-powering allow teams to perform better with high distances: prototypes can ascend more than with xenon focus with adaptative optics systems and also it solves the defocalization problems of xenon bulbs. Laser light consists of a very small band of wavelengths emitted in a narrow beam, which contrasts with light sources that emit incoherent photons in almost all directions. \\ Laser beam will spread much less than a beam of incoherent light. The beam reminds collimated over a distance wich varies with the square fo the beam diameter. Thus, a beam generated by a small laboratory laser such as a helium-neon laser spreads to about 1.6 kilometres (1 mile) diameter if shone from the Earth to the Moon. Moreover, every laser divergent beam can be transformed into a collimated beam by means of lens. In contrast, the light from non-laser sources cannot be collimated by optics.\\ By way of illustration, last year there were required at least 6 xenon arc lamps of 7KW to reach the top (40 meters high, less than half of the distance teams are supposed to reach this year) and they had a spread of 1.5m in front of the laser one which is is negligible at this height.\\ However, a solution with laser it is more expensive and there will be needed some adaptative optics to fill the photovoltaic array of the climbers. \\ Therefore, it seems that team's designs are approaching day by day to the beam-powered Laser Elevator as Brad C. Edwards proposed in "The Space Elevator: an ideal application for the free electron laser". But, how can laser principles be applied in a 20kg model of space elevator? What are the advantages and disadvantages? How to manage its costs? What models of adaptative optics should be made? We shall show the differences between the X-Prize Challenge scale (20kg climbers) and the theoretical proposals of the Space Elevator. What kind of laser is optimized for each case and why?
- Abstract document
- Manuscript document
IAC-07-D4.1.06.pdf (🔒 authorized access only).
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