Rocket launches are difficult. They’re expensive, they require an insane amount of fuel, their exhausts blast pollution into the atmosphere. One concept that seems straight out of science fiction could solve these problems: an elevator connecting Earth and space. And now Japanese engineers are about to start testing one.
On September 11, a team from Shizuoka University’s Faculty of Engineering will be launching a scale model of a space elevator into Earth orbit: two small cubic satellites just 10 centimetres (4 inches) a side, connected by a 10-metre (33-foot) steel cable.
A motorised box will travel back and forth along the cable, between the two satellites, while cameras in the satellites monitor its progress.
“It’s going to be the world’s first experiment to test elevator movement in space,” a university spokesperson told AFP.
Engineers have been dreaming of a space elevator for over 100 years, ever since Russian scientist Konstantin Tsiolkovsky came up with the idea after seeing the Eiffel Tower in 1895. The technology has made multiple appearances in science fiction since.
But the technical challenges involved in implementing a space elevator are gargantuan. For starters, it would need to be constructed of a material that’s light enough not to collapse under its own weight.
But this material would also need to be strong enough to withstand the tension induced by the centrifugal force acting on the elevator’s counterweight, way beyond Earth’s atmosphere, to keep the elevator upright.
It would also have to withstand the gravitational forces from Earth, the Sun and Moon, and the stresses induced by Earth’s atmospheric conditions, such as strong winds.
Japanese construction company Obayashi Corp., which is working with Shizuoka University, has previously announced that it hopes to get a space elevator operational by 2050. This would include a space station in geostationary orbit at an altitude of 35,000 kilometres (22,000 miles) and a tether in the Pacific Ocean.
It’s been eyeing off carbon nanotube technology for the cable. But that’s not really a possibility either. For one thing, we don’t currently have the technology to manufacture carbon nanotube even close to the scales required to produce a 96,000-kilometre (60,000-mile) cable.
For another, even if we could, the material is just not strong enough. Apply enough pressure, according to engineer Keith Henson, and the hexagonal carbon bonds become unstable – that cable could unzip like a run in a stocking.
But the Japanese team are still optimistic.
“In theory, a space elevator is highly plausible,” Shizuoka University engineer Yoji Ishikawa said. “Space travel may become something popular in the future.”
It’s possible that a new wonder material will emerge sometime in the next 30 years that will meet the requirements needed for a space elevator.
If and when that time comes, having the groundwork test data down will be invaluable.