Famously proposed by Arthur C Clarke, a space elevator is a little closer to reality.
As part of a $2 million compeition, a laser-powered robot has successfully climbed a cable nearly a kilometre long dangling from a helicopter.
The long-term goal is to create a cheap way of getting objects into orbit by simply lifting them to orbit with an elevator climbing a fixed cable.
The device, created by LaserMotive, made it to the top in a little over four minutes, half the time of the previous record holder, winning its inventors a $900,000 prize.
"The entire team is exceedingly satisfied that our system performed this well today," says the company, which is hoping to improve on its speed today.
The LaserMotive system uses a high-power laser array to shine ultra-intense infrared light onto high-efficiency solar cells, converting the light into electric power which then drives a motor.
The SpaceWard Foundation, which created the competition, says the project is a serious one. "Our goal is to generate enough interest in the project, so that within five years the Space Elevator basic building blocks can be demonstrated as feasible, and full-scale design and construction can begin," it says.
The biggest challenge is likely to be the creation of a tether strong enough and light enough to stay intact over the 60,000 mile distance to geosynchronous orbit. So far, the organisers have had no serious contenders.