Nanotechnology has thrown up some wild ideas in the past few years, but none can be quite as far-reachingly ambitious, if not fantastic, as that of NASA-backed project to launch a 100000-kilometre-long ribbon into space as a climbing frame for future pace vehicles. The idea of building an elevator to -pace may seem outlandish, but the consensus of leading aerospace scientists and researchers seems to be that it s not a question of if it will be built, but when. After launching, the competing forces of gravity at the lower end and outward centripetal acceleration at the far end would keep the ribbon under tension and stationary over a single position on Earth. The ribbon, once deployed, could be ascended by mechanical means to Earth orbit. If a climbing vehicle proceeds to the far end of the ribbon and releases, it would have sufficient energy to escape from Earth's gravity and travel to the Moon, Mars, Venus and the asteroids. An ocean-going platform, based on the current Sea Launch programme, would be used for the Earth anchor and located in the equatorial Pacific. The major risk of damage to the ribbon comes from meteor impacts and atomic oxygen erosion, but it is believed both could be mitigated through several methods, such as curved ribbon design and metal coating. Initially, it was suggested that a small, carbon-nanotube-composite ribbon (10 to 20 cm wide and microns thick) capable of supporting 990 kg payloads would be deployed from geosynchronous orbit using tour rockets and a 'magneto-plasma-dynamic' upper stage. Around 230 cargo climbers would be sent up the initial ribbon - one every 3-4 days - adding small ribbons alongside the first to increase its strength. After 2.3 years a ribbon capable of supporting 20000 kg cargo climbers would be complete. The design of the ribbon in the report is very specific and would have a two-square-millimetre cross-sectional area, be one metre wide and microns thick. The size and critical performance of the cable means that its production will be challenging. The cable length that we are proposing is 100000 km and its mass is 750000 kg. Although this in itself sounds daunting, many structures of similar size and complexity have been constructed. Lift Port Inc. is a privately hold company dedicated to the commercial development of the first elevator to space. The Space Elevator envisaged would not be a tower, or even an elevator shaft, just the elevator cable, without even any big motors at the top to pull things up. Vehicles and their payloads would have to pull themselves up the cable with their own motors and power supply.
Celestial stepping stones or pie in the sky?
Himmelstürmer senden Steine oder Pasteten in den Weltraum
Future Materials - fm ; Sep/Oct ; 6-9
2003
4 Seiten, 4 Bilder
Article (Journal)
English
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