A Trident missile is not the only way of putting a warhead anywhere in the world on target at short notice. A couple of weeks back I mentioned the Slingatron, which appeared in a US Army report on possible low-cost routes to space. The idea of a giant spiral Hula Hoop, somewhat bigger than a football stadium and oscillating at about nine revolutions a second, may seem a bit radical to some people. But – if you didn’t know already – no idea is too radical for DARPA. Budget documents reveal that they are not just doing studies. They have their very own Slingatron program , budgeted at at $3 million for 2006 rising to $4 million in 2007. Here’s how it’s described:
The Slingatron program will use modern engineering and physics concepts to accelerate masses to extremely high velocities. This mechanical mass acceleration concept, based on using centripetal body forces, is fundamentally different from electro-magnetic accelerators and hence avoids the limitations of those machines. Initial studies have demonstrated the fundamental feasibility of the Slingatron concept. This program will explore the concept’s bounding limits and seek to develop uses for the technology within those limits. Included in this program will be studies of the key technologies that will allow the accelerator to achieve very high projectile energies.
The program plans are nothing if not ambitious, aiming to:
- Fabricate experimental launchers.
- Demonstrate mass launchers that range in capabilities over three to four orders of magnitude.
- Demonstrate mass velocities on the order of several km/s and perhaps higher than 10km/s.
However, a perusal of DARPA’s latest plans showed no sign of the Slingatron. I checked with the Agency itself, and spokeswoman Jan Walker advised me:
“We did some preliminary investigation and results were not promising, so we decided not to proceed further.”
This could mean one of two things. Either the idea is too crazy even for DARPA, and it really cannot be made to work. Or else it does work, and the whole thing has gone underground, with a giant black program somewhere to construct one of these things. If a huge rotating structure appears in your neck of the woods, accompanied by occasional whooshing sounds and shooting stars…I’d advise you to stay quiet about it.
THERE’S MORE The U.S. Air Force has its own ideas about ground-based space launchers according to this piece in New Scientist magazine. The work is being carried out by LaunchPoint Technologies who are working on an innovative magnetic space launch system. It’s based on a sled which works like a maglev train running on a circular track. When it reaches a high enough speed – which might take a large number of revolutions – it is diverted off the track and off into space. LaunchPoint suggest that they will be able to put payloads into orbit for as little as $750/lb for their first system, perhaps later dropping to $100/lb, against current costs of $4,000/lb or more. Such a device could also be used to launch projectiles. The initial capital cost would be expensive – but then Trident submarines are not cheap either, and they’re not so useful for putting up satellites.
Mr. Hambling, an interesting article. Let’s try to be more accurate with regard to ballistic missile submarine satellite launches, however. Russia has been doing this with some success for quite a while. Here are only two, recent links: http://www.nasaspaceflight.com/content/?id=4513>nasaspaceflight.com
and
Bellona
Thanks for the comment Vigilis – I’m glad you brought up the Russian subs converted to satellite launch, this very example is discussed in my book Weapons Grade. However, such a system will never be able to match the launch rate or low cost-per-launch of a ground-based launcher – IF one can ever be successfully built.
That’s a big IF – but the rewards would be tremendous in terms of being able to put payloads into orbit cheaply. Personally I would say that the military are more likely than NASA to build the system that will be the stepping stone to space.
General Atomics of San Diego, Ca. (www.ga.com) has developed electrically driven linear linear motors to launch U.S.Naval aircraft from their newest aircraft carrier that is in construction today. These launchers can be scaled to launch any mass desired. Power generation and storage needs to be scaled to match the launch energy requirements as well.
Place such a system on the side of a very tall mountain peak, at the desired azimuth and elevation angle and you probably will have replaced the first stage of a mass launcher. The inital high altitude of the launcher reduces air drag as well.
If the mountain is near a sea port and rail access developed, the launch rate could be significant.
G forces would probably exceed what humans could endure unless the launcher were long enough to allow lower acceleration forces.
Why do you act like it is a surprise that DARPA canceled this? As was pointed out last time you posted about the project, it defies basic physics. Even DARPA notices such glaring errors sooner or later.
It doesn’t violate basic physics, but the risks are way too big even for DARPA. They’re not stupid and that’s what they will have been studying. The folks at http://www.slingatron.com/ still reckon it works though.
I don’t think any laws of physics are being threatened here – DARPA and the US Army are not as stupid as you seem to imply – check out the papers listed
here and The Spiral Slingatron Mass Launcher in particular.
Then again, there were people saying the Wright Brothers had it all wrong too
Sorry, scientific papers are here:
http://www.slingatron.com/publications.htm
Especially this:
http://www.slingatron.com/Publications/Linked/The%20Spiral%20Slingatron%20Mass%20Launcher.pdf
On the physcis of using a slingatron for space launch
Tim, it doesn’t violate basic laws of physics. Sometimes asymmetrical (i.e. ungainly big frying pans) would do the problem just fine. Besides, to get acceleration down to 3gs you’d need something like 30 miles(correct me if I am wrong) of railgun whereas you could curve that path and make it a dish. It’s still better than using rockets for everything.