Abstract

The SPICE Geoengineering project is investigating the feasibility of pumping particles into the stratosphere at an elevation of 20km, with a view to replicating the effects of large volcanoes. By injecting particles that scatter light at visible wavelengths, but not in the infra-red, some of the incoming sunlight will be reflected back into space without interfering with the earth’s own radiated light. The seminar will consider the structural issues associated with providing a tether to a balloon located at 20km, which will have to withstand not only the high axial forces due to the weight of the tether but also internal pressures as high as 6000 bar. Consideration will be given to some of the options for the material of the tether, its form of construction, and the ways in which it might be anchored. Alternative means of getting material to 20 km will also be considered, including an outline design of a tower 20km tall made from advanced fibres. It is concluded that this is not a serious prospect with any material that is currently envisaged!