Oct
30
2007

# Space elevator update, 2007

### Million dollar prize unclaimed

Space elevator: Artist Pat Rawling's concept of a space elevator viewed from the geostationary transfer station looking down along the length of the elevator toward Earth.
The concept of building an elevator to carry materials up to space orbit was proposed by Arthur C. Clarke in his 1987 science fiction novel, 2061: Odyssey Three. Spaceward Foundation, which partnered with NASA holds two space-elevator-related competitions - the Tether Challenge and the Beam Power Challenge.

### Tether Challenge

The tether competition is a perpetual dare for any group to present a tether that is at least 50% better than last year's best offering. Tethers are ranked according to strength and weight.

The strength of a material is measured in Giga-Pascals (GPa) and its weight, or more precisely, its density, is measured in grams per cubic centimeter {g/cc). In order to build the Space Elevator, we need a material that has a specific strength of 80-100 GPa-cc/g. elevator2010.org

The best entry in 2005 tether competition, using spectra 2000 fiber (Honeywell) had specific strength of 2.8. The best entry in 2006 tether competition, using Zylon fiber (Toyobo Inc.) had a specific strength of 3. This year's \$500,000 offered to any team that could produce a tether with a specific strength of 4.5 went unclaimed.

### Beam Power Challenge

The Beam Challenge tests the climbing ability and weight-bearing capability of robots scaling a cable.

The climbers net weight is limited to between 10 and 25 kg [22 - 55 lbs], and they must ascend the ribbon at a minimum of 2 m/s. [6.6 feet per second] Climbers will be rated according to their speed multiplied by the amount of payload they carried, and divided by their net weight. For example, a 15 kg climber, carrying 5 kgs of payload at 2.5 m/s will have a score of 5 · 2.5 · / 15 = 0.83

Climbers have to scale the ribbon while carrying some amount of payload, using only power that was transferred from the ground using beamed power. Power is unlimited. Some teams used mirrors and sunlight instead of laser beams. They were big trouble on cloudy days, though. The University of Saskatchewan Design for Space (USST) team came in first but missed the big money prize by a few seconds. Click here to see a video of the USST climber attempt.