OTTAWA • Press "S" for space?

A Canadian company wants to build a tower that would allow astronauts to take a lift part way into orbit. The tower would be 20 times higher than Dubai's Burj Khalifa, currently the world's tallest building that soars 830m into the sky.

The "space elevator" idea was first proposed in 1895 by Russian scientist Konstantin Tsiolkovsky after he saw the Eiffel Tower in Paris, and was revisited nearly a century later in a novel by Arthur C. Clarke. But technical barriers have always kept plans stuck at the conceptual stage.

Last month, however, Thoth Technology was granted a US patent for its "space elevator", which is modest in comparison but promises to significantly reduce the cost of space travel.

The Canadian firm envisions building a 20km-high tower with a platform at the top "for launching payloads, tourism, observation, scientific research and communications". The tower would be built of pressurised, stacked cells, according to the patent. "Elevator cars may ascend or descend on the outer surface of the elevator core structure or in a shaft on the interior of the elevator core structure."

Hauling payloads on a lift into near space would virtually eliminate atmospheric drag, and launching them into space from the stratosphere would require less fuel. Thoth estimates this would cut the cost of space flight by one third.

In his 1979 novel, The Fountains Of Paradise, Clarke proposed delivering payloads using a huge cable anchored to an orbiting platform. But this required a 35,000km-long cable - which cannot be built using existing materials - and a counterweight the size of a small asteroid.

AGENCE FRANCE-PRESSE