York University researchers have designed a prototype of a space elevator that would carry equipment and tourists to 20 kilometres above Earth.
"For decades, scientists have been grappling to find a more efficient means of getting payloads into space," says Brendan Quine (right), professor of space physics and engineering in York's Faculty of Science & Engineering, who is heading the project. A paper detailing the design was recently published in the journal Acta Astronautica; it is co-authored by York space engineering Professor George Zhu and graduate student Raj Seth.
"Rocketry is an extremely inefficient way of getting equipment into space," Quine says. "In the initial stages of flight, you’re wasting an enormous amount of energy fighting gravity and atmospheric drag."
Constructed from Kevlar, the free-standing structure would use pneumatically-inflated sections pressurized with lightweight gas such as hydrogen or helium, to actively stabilize itself and allow for flexibility. A series of platforms or pods, supported by the elevator, would be used to launch payloads into Earth's orbit.
The design intends to circumvent problems associated with the space tether concept, first popularized in the 1970s. Begun as science fiction, the tether evolved into a complex design for a cable and counter-balanced mass system; the counterbalance hangs in orbit, like a small asteroid, with a cable extending tens of thousands of kilometres to Earth.
Material strength constraints, the need for in-space construction, as well as maintenance concerns have kept the scientific community searching for alternatives.
Left and below right: A prototype of the space elevator shows the free-standing structure constructed from Kevlar. It uses pneumatically inflated sections, pressurized with lightweight gas such as hydrogen or helium, to actively stabilize itself.
"All concepts have thus far relied on the manufacture of incredibly long and strong cables. However, the materials we have today are simply not strong enough to manufacture a cable of that length. It would not even be capable of supporting its own weight," Quine says.
The design aims for a lofty 20 kilometres above sea level. However, researchers hope it can be scaled to access higher altitudes.
"Eventually, we could foresee going as high as 200 kilometres," Quine says. By contrast, the world’s tallest buildings have yet to reach a kilometre in height. The Burj Dubai, currently under construction, holds the record, having surpassed 800 metres.
Seth, a graduate student in York’s Department of Physics & Astronomy, notes that an innovative construction method is a key element of the prototype. Stacks of pods containing control and stabilization machinery are embedded in its core structure, and then pulled o
ut and extended vertically via a system of rollers.
"You can visualize it as a system of nesting segments that roll out vertically and snap into position, much like a telescoping wand," Seth says. "You’re not constructing externally, but rather, from internally."
The structure’s position would be maintained by an active control system that corrects its centre of gravity using methods such as pressure balancing and gyroscopic stabilization. The system would also counter the forces of nature, says Quine. "During high wind conditions, the structure will need to lean into the wind in order to cancel out external forces," he says.
The team has filed for international patent protection for their design, in partnership with space technology company, Thoth Technology Inc.
"We hope our design will help to realize the dream of a space elevator within the next decade," Quine says.