End of their tether

Teams from industry and universities joined amateur enthusiasts last weekend to compete in NASA’s 2005 Beam Power and Tether challenges — two contests to build a climbing robot and high-strength tether for possible application in the construction of a space elevator.

Engineers believe that in a couple of decades it will be possible to build a fixed line from Earth to space to carry an elevator. The line would consist of a high-strength tether made from carbon nanotubes. Elevator cars would travel up and down the tether, powered by highintensity, Earth-based lasers aimed at photovoltaic cells on the cars’ undersides.

To speed up research into technologies needed for such a project, NASA offered £28,000 prizes to innovators who could reach two key milestones. The competition, sponsored by the non-profit Spaceward Foundation, took place at the NASA Ames Research Centre in Mountain View, California.

The Beam Power Challenge, designed to create a solution for powering the space elevator, required teams to build a robotic climber that could scale a 61m cable, powered by photoelectric cells capable of converting light from a 10,000W industrial searchlight into electricity.

The challenge was to send the robot 50m up the ribbon in under 50 seconds. In the Tether Challenge, the goal was to create a 2-gram tether tougher than a 3-gram band made from a high-strength material called Zylon.

Although neither challenge was met and the prizes were unclaimed, NASA said the results were promising. In the Beam Power contest, no robot met the speed requirement, but the University of Saskatchewan Space Design Team set the height record at 12m.

A team from Centaurus Aerospace produced the strongest tether, but could not beat the Zylon tether by the required margin of 50 per cent.

Next year, NASA plans to increase the reward to £112,000 for each competition, though the technical criteria will be made harder.