Symposium on the far future: renewed visions (D4.) Space Elevator System Infrastructures (1.)

摘要

The single most difficult task in building the Space Elevator is achieving the required tether strength-to-weight ratio, in other words, developing a material that is both strong enough and light enough to support a 100,000 km long tether on which elevator cars or climbers can move up and down. In order to fuel the development of such super strong materials for the potential future use in a Space Elevator cable (or for other structural aerospace applications) the so-called Tether Challenge has been introduced by NASA. It is the second category of the space elevator games that are managed by the Spaceward Foundation. The competition requires a 50 While theoretically carbon nanotubes can have tensile strengths beyond 200 GPa (some proposals predict strengths up to 1TPa), in practice the highest tensile strengths ever observed in single/multi-walled tubes range between 50 GPa and 150 GPa. However, even the strongest fibre made of carbon nanotubes is likely to have notably less strength than its components. Improving tensile strength depends on further research on purity and different types of nanotubes. The paper discusses the status of the art in advanced materials as highlighted by the results of the Tether Challenge at the Spaceward Games since 2005. In addition recent advancements in CNT fibre engineering in Europe and the US are presented where strength improvements of roughly 100 over the last couple of years have been achieved, demonstrating the basic truth that super strong CNT threads can be made.