A US company has launched a fund-raising campaign to build a prototype “slingatron” that could be used to propel a 100 g object to a speed of one kilometre per second. HyperV Technologies, based in Virginia in the US, is now attempting to raise $250,000 via the crowd-funding website Kickstarter to build the device, which it says will pave the way for a full scaled-up version that can launch much heavier cargo into space.

Spin me right round

A slingatron is based upon an old-fashioned weapon known as a “sling” – it involves a heavy mass on the end of a rope, which a person whirls around their head with increasing frequency before letting go, sending the object flying. However, with the slingatron the rope is replaced by a spiral track spinning at a constant frequency. When an object is released from the middle, it follows the track round with an increasing radius, getting faster and faster as it does so. The larger the final radius – and the greater the spin frequency – the faster the object travels when it leaves.

The idea for this sort of mechanical propulsion is not new. In 2006 it was revealed that the US Defense Advanced Research Projects Agency budgeted around $3m to explore whether a slingatron could accelerate masses to extremely high speeds without using rockets, before claiming that the approach was unpromising.

HyperV claims that its last prototype, the 2-m-tall “Mark II Slingatron”, successfully accelerated a 230 g object to 100 m s^–1. The challenge with the next, crowd-funded prototype is to demonstrate that a 5-m-wide slingatron can generate speeds that are 10 times greater, and to pave the way for an even bigger slingatron that can launch cargo faster than 11 km^–1 – quickly enough to go into orbit. HyperV believes that the concept will be far cheaper than conventional rocket launches, although it will only be suitable for non-human cargo that can withstand a g-force of 60,000.

Interesting approach

Dennis Bushnell, chief scientist at NASA’s Langley Research Center in Virginia, points out that a NASA study conducted early this century found slingatrons to be “the most interesting ‘gun’ approach”, in terms of cost and capacity, to launch cargo into space. “It is well worth serious further study,” he says. “[But] whether [HyperV] has pockets deep enough to plough through the issues is to be determined.”

However, Jim Fiske at California-based LaunchPoint Technologies, which has previously investigated a method to launch objects using a stationary magnetic rail, is sceptical of HyperV’s idea. “I must confess that I don’t see much advantage in spending money on such a project,” he says. “Wouldn’t it make far more sense to accelerate the vehicle directly and leave the track stationary?” Indeed, money may well be a stumbling block – currently, only $24,760 had been pledged to the project. “We knew going into it that it was a long shot,” says HyperV spokesperson Chris Faranetta. “Our main objective with the Kickstarter was to get the public thinking and caring about the slingatron.”

Take a look at this video to learn more about HyperV’s slingatron project.