In a few weeks, scientists from all over the world will once again meet in New Mexico to participate in an ambitious competition:
Some researchers will unveil robots, powered by solar panels, that will climb long lengths of cable. Others will demonstrate materials so light and strong that mile-long stretches of the stuff could be hung in the air without snapping. And some will highlight their plans to launch satellites carrying sets of mini-probes tethered together, to discover how they behave in space.
All these different projects are united by one extraordinary goal: to build a stairway to heaven. Each of the groups that will gather in New Mexico is competing to win a Nasa prize set up to encourage entrepreneurs to start development work on the technology needed to create a space elevator. Such a device would involve constructing a 23,000-mile cable that could pull men and goods into orbit without blasting them there on top of expensive, and dangerous, rockets.
'I think there are going to be lots of people that rise to this challenge,' said Michael Laine, president of the Washington-based company LiftPort, which will take part in the competition. 'We're at the beginning of something really great.'
The key feature of a space elevator would be the use of a satellite that will orbit almost 23,000 miles above Earth. At this altitude, known as geostationary orbit, the orbital period of a satellite moving around the globe matches Earth's rotation. The craft then hovers over a single spot on the equator.
However, a space elevator would have one extra key feature: a massive cable would be lowered from it to link it to the ground where it would remain fixed, like a tube line to the stars.