Is A Space Elevator Possible Using Today's Technology?

One of the biggest challenges to space travel is escaping Earth's orbit. Whether it be traveling to an orbital space station, going to the moon, or setting out for other planets, breaking free of Earth's orbit is the first, and biggest, step.

Space elevators, long a staple of science fiction, promise an innovative way to overcome Earth's orbit. According to the premise, a long cable, anchored to Earth at the equator, provides a way to move people, supplies, and vehicles into space. By having a counterbalance at the far end of the tether, the centrifugal forces created by Earth's rotation would overcome Earth's gravity, resulting in the cable remaining taut and vertical.

Despite being described as early as 1895 by Russian scientist Konstantin Tsiolkovsky (via NASA), materials strong enough to build a traditional space elevator do not yet exist or are prohibitive to make in the necessary quantities. With some modifications, however, an elevator may be possible. Scientists have been working on ways of making the space elevator a reality using current technologies and materials. These efforts have fallen into at least two separate camps.

The most promising method is one proposed by York University's George Zhu, a professor of mechanical engineering who has co-authored a study on the idea, according to Mashable. The method would involve using two cables, rather than one, much like a cable car system.

"It's like cable cars, moving from a lower spacecraft to an upper spacecraft," Zhu explains. "They keep going in a loop, they keep it stable. In technical terms, it's almost done... I'm very confident we will have it by the 22nd century."

Using two cables, instead of a single one, would make it much easier to keep the elevator stable and prevent cross-winds in Earth's atmosphere from buffeting it about. The two cables would be suspended above the Earth's surface, rather than anchored to it, further reducing stresses. Even with a rocket required to reach the lower level of the elevator, the overall cost would still be significantly lower than using a rocket for the entire journey.

While Zhu believes this design is possible in the 22nd century, the project's lead, Brendan Quine, associate professor of York's department of earth and space science and engineering, seems more optimistic about the time frame.

"I don't want to understate the technological issues (but) I think it would be realizable within 10 years," he told Toronto.com.

Another, more ambitious project, is one that would reverse the direction of the space elevator. Instead of being anchored on Earth, Zephyr Penoyre from the University of Cambridge and Emily Sandford at Columbia University, propose anchoring the space elevator on the Moon.

As MIT Technology Review explains, the cable would pass through the Lagrange point, the point between the Earth and Moon where their gravitational forces cancel each other out. This would be the ideal spot to build a sort of "base camp" where construction projects and scientific experiments could be safely conducted. Unlike Earth's orbit, the area would offer true zero-g, with no gravitational forces pulling in any direction.

This particular type of space elevator would not be as useful as traditional proposals for breaking free of Earth's orbit, or activities immediately in its vicinity. It would, however, significantly reduce the cost and challenges involved in traveling to and from the Moon, making colonization a very real possibility.

The best thing about both of these proposals is that they can be built entirely with materials — such as titanium and aluminum — that are widely available, making a space elevator a very real possibility using today's technology.