A Canadian space firm is one step closer to revolutionising space travel with a simple idea – instead of taking a rocket ship, why not take a giant elevator into space?
Thoth Technology Inc has been granted both US and UK patents for a space elevator designed to take astronauts up into the stratosphere, so they can then be propelled into space.
The company said the tower, named the ThothX Tower, will be an inflatable, freestanding structure complete with an electrical elevator and will reach 20km (12.5 miles) above the Earth.
"Astronauts would ascend to 20km by electrical elevator. From the top of the tower, space planes will launch in a single stage to orbit, returning to the top of the tower for refueling and reflight," Brendan Quine, the tower's inventor, said in a statement.
Traditionally, regions above 50km (31 miles) in altitude can only be reached by rocket ships, where mass is expelled at a high velocity to achieve thrust in the opposite direction. Quine said in the patent that rocketry is “extremely inefficient” and that a space elevator would take less energy.
In the patent, Quine explained that rocket ships expend more energy because they “must counter the gravitational force during the flight by carrying mass in the form of propellant and must overcome atmospheric drag”.
In contrast, by using an elevator system, “the work done is significantly less as no expulsion mass must be carried to do work against gravity, and lower ascent speeds in the lower atmosphere can virtually eliminate atmospheric drag”.
“Part of the limitation on space travel is the cost of getting to space,” Quine said. “The tower could change space travel because professional rockets are very energy intensive and not very environmentally friendly.”
The elevator cars can also be powered electrically or inductively, eliminating the need to carry fuel, Quine wrote. The technology offers a way to access space through reusable hardware, and will save more than 30 per cent of the fuel of a conventional rocket, Thoth Technology said in a July statement.
Quine said when a traditional rocket ship launches from Earth, it flies vertically about 15-25km (9-15 miles) before hitting drop-off stages, when sections of the rocket drop back to Earth, usually falling into the ocean. During the final stage when it enters space it is flying horizontally.
The ThothX Tower will eliminate the need for the vertical flight and drop-off stages, which are very energy intensive.
“In our concept, you ascend electrically and remove the whole vertical launch phase,” Quine said. “Then you get into a space plane, which is like a passenger jet, and take off horizontally.”
An elevator to space has been a long-standing idea as an alternative to rocket ships, but has always been believed as unfeasible because no known material can support itself at such a height. Thoth’s design sidesteps this problem by building the elevator to 20km so it sits within the stratosphere rather than all the way in the geostationary orbit, where satellites fly.
The tower, pneumatically pressurised and actively guided over its base, could also be used for wind-energy generation and communications, according to Thoth Technology.
Quine said the tower will also be open to tourists, providing a way for people to experience space-like conditions without losing gravity.
Citing science-fiction author Arthur C Clarke's proposal of a space elevator in his 1978 novel The Fountains of Paradise, Quine explains in the patent that a space elevator could be constructed with a cable and counterbalanced mass system.
Thoth's president and chief executive Caroline Roberts said space travel, coupled with self-landing rocket technologies being developed by other companies, will bring a new era of space transportation.
“Landing on a barge at sea level is a great demonstration, but landing at 12 miles above sea level will make space flight more like taking a passenger jet,” she said.