Feeds

Space elevators, vacuum chutes: What next for big rocket tech?

How boffins hope to escape long shadow of the V2

Secure remote control for conventional and virtual desktops

More bangs for your bucks

In the 1960s, ballistics engineer Gerald Bull persuaded the Canadian and US defence departments that it might be possible to fire a payload into space from a very large gun.

Cue Project HARP (High Altitude Research Project), which rolled out a US Navy 16in (406mm) piece to lob projectiles over the Atlantic from a base in Barbados.

The HARP gun firing, and as it is today, abandoned in Barbados

The HARP gun in action, and abandoned today

With an initial barrel length of 20m, later extended to 40m, HARP eventually managed to propel a 180kg slug at 3,600m/s to an altitude of 180km.

The project was cancelled shortly after this 1966 high, and Bull went on to develop the Iraqi-funded "Project Babylon" supergun, ostensibly a means of getting satellites into orbit.

Bull's 1990 assassination brought Project Babylon to an abrupt halt, but US scientists continued to work on the spacegun concept.

In 1992, the US fired up its Super High Altitude Research Project (SHARP) light gas gun. SHARP worked by igniting methane to drive a piston which in turn compressed hydrogen, all within a pump tube. At the required moment, the pressurised hydrogen was released behind a projectile sitting in the launch tube, which exited the 10cm diameter, 47m-long "barrel" at tremendous speed.

Artist's impression of the Quicklaunch system

Quicklaunch

SHARP was able to accelerate a 5kg projectile to 3,000m/s. A proposed giant version of the gun - the "Jules Verne Launcher" named in honour of the man whose novel From the Earth to the Moon described a cannon-launched manned Moon mission - never got off the drawing board.

The light gas gun isn't entirely dead, though, as SHARP scientist Dr John Hunter continues to fly the flag with the aquatic Quicklaunch.

The Quicklaunch system will overcome one hurdle facing ground-launched projectiles - that of air resistance slowing their progress through the atmosphere - by deploying rocket motor boost at altitude.

What it won't be able to do, though, is put people into space. Jules Verne's vision didn't encompass the effects of enormous G-forces on the human body, which would relegate any space gun to lifting inanimate objects.

What we need, therefore, is a gentler way to fly, and what better than to float skywards using the lifting power of gas?

This sedate approach relies on the lighter-than-air properties of hydrogen or helium to provide lift. Last year, the Red Bull Stratos mission saw Felix Baumgartner soar to 39,068.5m under a substantial helium-filled globe, so what's to prevent a balloon drifting ever upwards into orbit?

The launch of the Red Bull Stratos. Pic: Red Bull

The Launch of the Red Bull Stratos in 2012

Well, for starters, you've got the fact that as you ascend, the lifting gas expands, meaning you've either got to have a gargantuan envelope to start with, or an envelope capable of stretching to gargantuan proportions, or you'll have to vent some gas, meaning loss of lift.

Wind conditions in the lower atmosphere are severe, so the larger your balloon at ground level, the more vulnerable it becomes as it rises.

To address these issues, the volunteers who form the US's JP Aerospace have drawn up a three-stage "Airship to Orbit" concept, with each of the system's stages designed to operate in its particular operating environment.

Firstly, The "Ascender" hybrid "atmospheric airship", using a combination of buoyancy and aerodynamic lift, is steered by electric-driven propellers to around 42,000m.

There, it docks with a floating "Dark Sky Station", which is the jumping-off point for the third stage: "an airship/dynamic vehicle that flies directly to orbit".

In order to get any kind of lift at that altitude, the orbital vehicle needs to be quite large - over 1.6km long, according to JP aerospace. Once it's ascended to 60,000m, electric motors gradually accelerate it to orbital velocity.

It's an audacious plan, but hardly more bold than the Lofstrom loop - a 2000km-long maglev orbital launch track theoretically capable of flinging manned vehicles of up to five tonnes into orbit.

Artists impression of the loop. Pic: Keith Lofstrom

The Loftsrom Loop

The loop is formed by a sheath containing an iron tube which spins longitudinally within the sheath, causing it to rise from the ground into a tethered arc. When a payload is placed onto the loop, it's magnetically levitated and driven forwards, gradually gaining speed until it's lobbed into orbit.

Related maglev concepts include a circular configuration, around which payloads are accelerated until they can be projected spacewards.

On a more realistic note, NASA has mulled the use of magnetic levitation in hybrid launch technologies, where it might be deployed to give vehicles that first kick.

NASA concept drawing of a maglev launcher. Pic: NASA

NASA's concept of a maglev launch platform

These might propel scramjet-powered vehicles to the velocity necessary for their engines to cut in, without the need for conventional rocket-powered assist.

The StarTram is an advanced version of the maglev-assist idea, in which spacecraft would accelerate in a vacuum up a tube to an altitude of 22km, after which conventional motors would do the rest.

Sketch of the StarTram tube. Pic: StarTram

StarTram

The big downside of maglev launchers is the quantity of juice required to drive them. At Loftsrom Loop scales, just keeping the thing elevated would require an estimated 200MW, meaning quite shocking electricity bills for the operator.

Top 5 reasons to deploy VMware with Tegile

More from The Register

next story
Antarctic ice THICKER than first feared – penguin-bot boffins
Robo-sub scans freezing waters, rocks warming models
I'll be back (and forward): Hollywood's time travel tribulations
Quick, call the Time Cops to sort out this paradox!
Your PHONE is slowly KILLING YOU
Doctors find new Digitillnesses - 'text neck' and 'telepressure'
Reuse the Force, Luke: SpaceX's Elon Musk reveals X-WING designs
And a floating carrier for recyclable rockets
NASA launches new climate model at SC14
75 days of supercomputing later ...
Britain's HUMAN DNA-strewing Moon mission rakes in £200k
3 days, and Kickstarter moves lander 37% nearer takeoff
prev story

Whitepapers

Go beyond APM with real-time IT operations analytics
How IT operations teams can harness the wealth of wire data already flowing through their environment for real-time operational intelligence.
5 critical considerations for enterprise cloud backup
Key considerations when evaluating cloud backup solutions to ensure adequate protection security and availability of enterprise data.
Getting started with customer-focused identity management
Learn why identity is a fundamental requirement to digital growth, and how without it there is no way to identify and engage customers in a meaningful way.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Simplify SSL certificate management across the enterprise
Simple steps to take control of SSL across the enterprise, and recommendations for a management platform for full visibility and single-point of control for these Certificates.