Patent approvals don't get much more 'out there' than this. A gigantic "space elevator" tower standing some 20 kilometres (12.4 miles) high has been patented in the US and the UK by a Canadian company that's seeking to change how astronauts get into space.

Thoth Technology, which specialises in technology related to space travel and defence, has dreamed up ThothX Tower: a freestanding, partially inflated structure with a runway at the top that can launch spacecraft directly into Earth's stratosphere.

"Astronauts would ascend to 20 km 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 refuelling and reflight," said Brendan Quine, the inventor of the space elevator concept, in a press release.

The idea is that by launching spacecraft into orbit from this height – which is 24 times taller than the world's current tallest structure, Dubai's Burj Khalifa in the United Arab Emirates – as much as 30 percent of the fuel used in a conventional rocket launch could be saved, ostensibly making it easier, cheaper and more environmentally friendly to get astronauts into space. As Quine puts it in the patent:

*Traditionally, regions above 50 km in altitude can only be accessed using rocketry, where mass is expelled at high velocity in order to achieve thrust in the opposite direction. This process is extremely inefficient as rockets must counter the gravitational force during the flight by carrying mass in the form of propellant and must overcome atmospheric drag.

In contrast, if a payload is hauled to space or near space along 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.*

While the concept of using such super-high towers for astronomical purposes isn't new (sci-fi writer Arthur C Clarke suggested the concept back in the 1970s, as observed by the patent), we've never had a means of building such an immense structure that could support its own weight and withstand high winds.

The ThothX Tower would get around this by virtue of its partially inflated design, with each segment of the tower using pneumatically pressurised cells filled with air or some other? gas. This could provide a lightweight, manoeuvrable form, with the entire structure stabilised by gyroscopes and active control machinery, ensuring that the tower remains in a straight, vertical position as much as possible.

"Landing on a barge at sea level is a great demonstration, but landing at 12 miles [19.3 km] above sea level will make space flight more like taking a passenger jet," said Caroline Roberts, Thoth president and CEO.

In addition to providing an elevated launch and landing platform for space exploration, the space tower's designers say the structure could be used for any number of pursuits, including wind-energy generation, communications, and even tourism.

"As a tourist destination, the elevator platforms provide stations located at fixed attitudes from the surface for observation," writes Quine in the patent. "The elevator platforms provide the means to safely access a region of space with a view extending hundreds of kilometres."

But don't cancel your trip to Disney World just yet. As promising as the space elevator looks, Thoth Technology hasn't yet confirmed any concrete plans to actually build this thing – and it's likely there'd be significant regulatory hurdles to overcome if that's the company's plan. We'll be watching.