Photo credit by BBC
By Ahmad A. Malik
“The space elevator will be built about 50 years after everyone stops laughing.”
- Arthur C. Clarke, 1985
“It’ll be built 10 years after everybody stops laughing, and I think they have stopped laughing.”
- Arthur C. Clarke, 2003
Japanese construction giant, Obayashi Corporation, announced plans last week to construct an elevator reaching into geospatial territory by the year 2050. The announcement comes in light of the company realizing their industrial capability to construct this technologically advanced system.
The elevator is expected to reach 59,652 miles into space, servicing the International Space Station. For reference, space lies beyond the Kàrmàn Line at an altitude of 60 miles from Earth’s surface.
By using magnetized robotic cars traveling up a powerful rail counterweighted by Earth’s rotation, the elevator is expected to ferry materials and astronauts to the ISS, thereby vastly reducing the need for risky, costly shuttle launches, while pioneering the greatest transportation revolution since the invention of the railroad.
Currently, it costs around $10,000 per pound to transport cargo to space. With the space elevator, it is estimated to cost closer to $400 per pound. For reference, on JetBlue it costs about $1 per pound to check luggage. Additionally, the payload size, very much unlike a limited spaceship, can be built to practically any scale. A tether increased by only a few inches can increase the weight capacity of the elevator one hundred fold. The Obayashi Corporation says it has the necessary tools to do just that.
The expected travel time for the elevator is seven days, while a traditional shuttle launch takes two days. However, shuttle launches are limited and costly. With a space elevator, it would be able to send materials multiple times a day, effectively cancelling out the increased travel time.
The space elevator was a concept born out of science fiction, but now is considered the most viable option in next-generation space travel. The process will require no fuel and will incur no turbulence – it more closely resembles a train than a space shuttle. As such, the risks and costs associated with shuttle launches are tremendously decreased.
Yuri Artsutanov proposed the idea of space elevators in 1960, but the idea wasn’t taken seriously since any such technologies or materials strong enough to create a structure so robust did not existed. That all changed with Sumio Iijima’s discovery of carbon nanotubes in 1990.
The space elevator will use these carbon nanotube as a sort of track on which the elevator rides. This end of this track is attached to an offshore sea platform, counterweighted by an object on the other end, 59,652 mile away.
The track works similar to a game of tetherball, where a ball is attached to an upright pole via a string. In this example, the pole functions as the Earth, the string is collection of carbon nanotubes, and the ball is the counterweight. So now, the ball must be traveling fast enough to keep the string taut. The taut string is now, theoretically, strong enough to function as a pathway between the pole and ball. This speed is generated naturally through the spin of the Earth, which rotates at around 1,000 miles per hour. This is the entire idea behind the space elevator.
Carbon nanotubes come in to play as the string or railway between earth and the ISS. These elements are 100 times stronger than steel and are as flexible as plastic. Scientists create fibers from these carbon nanotubes, and create threads that will form the track. Before carbon nanotubes, no material was strong enough to form a track. Once constructed, it will be the largest structure mankind has ever made – looming over the Bourge Khalifa, the tallest structure in the world, literally, astronomically. Researches at Obayashi are currently working on created nanotubes long enough to form the track.
“The tensile strength is almost a hundred times stronger than steel cable so it’s possible,” said Obayashi research and development manager, Yoji Ishikawa. “Right now we can’t make the cable long enough. We can only make 3-centimeter-long nanotubes, but we need much more. We think by 2030 we’ll be able to do it.”
As for the elevator itself, a series of lifters will be constructed to travel along the carbon nanotubes. The lifters will vary from five to 20 tons in capacity, the latter being able to carry almost 13 tons of payload. With this capability, researches can send items like satellites to solar-powered panels into space. Humans will be able to ride this elevator as well, at an approximate speed of 118 miles per hour.