Scientists study ‘moon catapult’

A plan to support a moon mission using a giant slingshot is to be studied by researchers at Glasgow University.The three-month study will look at the feasibility of propelling food and equipment from earth to the moon. The theory is that cargo could be transferred using giant cables and the power of the moon and earth's orbits. The scientists, who have won funding from the European Space Agency, said the system could replace rockets and would be cheaper in the long-term.

The study, by Dr Gianmarco Radice and Prof Matthew Cartmell, will look at the maths surrounding the system, rather than creating a physical model. The cables used to propel items would be many kilometres long and could be made of Kevlar, tungsten or graphite. The idea is that another set of long cables could be built on the moon to pull the items towards it.

The scientists said there was renewed interest in lunar exploration, with the possibility of building bases on the moon in the next 25 years, so such a system could become a useful reality. Dr Radice said: "Tether systems are an extremely attractive possibility for space transportation as they do not require any fuel. "The cargo is transferred from one orbit to the other using the orbital velocity of the system. "There are a number of practical issues that have to be addressed, as the cables are kilometres long and have to be extremely resistant, but this could provide an efficient method of transporting goods between the earth and moon".

They aren't talking about connecting the Moon to the Earth by cables. Here is a bit more detail:

It sounds fantastical to the layman, but this device resembles a double-ended slingshot, powered by a central motor. Designed to remain in orbit around the earth, it would fling outgoing loads into space while also catching incoming loads and handing them safely down to Earth. The system works by building up speed, like a slingshot, until it has enough momentum to fling its load off into space. The attraction of this ?motorised tether system? would be its long-term cost-effectiveness. As Professor Cartmell says, ?It?s actually virtually free once it?s up there.? And he hopes that its curiosity value will do a lot to regenerate the public?s interest in space projects. - link