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Magnetic Ring Could Launch Satellites, Weapons
MattSparkes writes, "A new study funded by the US Air Force has suggested a cheaper method of sending satellites (possibly missile weapons) into orbit. A 2-km-wide ring of superconducting magnets would contain and propel a payload, accelerating it over a period of hours, before suddenly flinging the satellite into space at 23 times the speed of sound. The satellites would be engineered to withstand the g-forces encountered (2,000 g), and be cased in an aerodynamic shell. A two-year study has been commisioned and will begin within a few weeks at LaunchPoint Technologies in Goleta, California." New Scientist points out that if such a launch ring were built, it would instantly become "one of the most important targets on the planet."
Space burials (presumably of cremated remains). At $200 each (plus cremation) I am sure they could sell a few thousand of these per year. Now if they could only figure out a way to allow living people to withstand 2000g of acceleration, space tourism might actually be affordable.
I Am My Own Worst Enemy
"I also wonder how much energy it would use to do such a thing compared to the energy expended launching the payload using a conventional solid/liquid fuel rocket."
;-)
I don't know the numbers, but the bulk of a conventional rocket fuel us used up getting the last bit of fuel to near orbit. So the for example, the first 100kg of fuel is used lifting the last 10kg of fuel.
With this ring type of accelerator, there is no basically no fuel onboard to used to enter orbit, so you don't need the resulting mass to accellerate is 100x smaller. Look how big the Saturn 5 was just to lift a basically small payload. Most of the lifting was lifting the fuel to do the lifting.
That novel did not describe a ring. The electromagnetic launchers in that book were both "simple" linear accelerators. :)
In the launch-ring article, I noticed the air-resistance problem being mentioned, during the initial acceleration phase.
I might suggest this idea as pointing out a solution to that problem.
What about using this thing to shoot water/food/structural materials into space? That is where the savings really come into play. If there is to be a moon base, all the water has to be shipped up there. People need lots of water, so cutting the cost per kilogram to 1% of current levels is a very big deal.
This post climbed Mt. Washington.
The reason that most meteors don't hit the ground is because they are so small. The one that do hit the ground and are found right away often have FROST on them since they were so cold in space. As for exploding into a million pieces, meteors aren't designed for reentry.
Any compentent aeroshell engineer could design a case that would protect the payload (such as a capsule covered with the stuff they use for ablatively cooling rocket nozzles). The big concern usually with burning through airframes isn't that we don't have materials that can withstand the heat and friction; it is that those materials typically aren't very light-weight or are too expensive.
Besides, once the track is set up, it should be easy to try out new aeroshell designs! One of the stumbling blocks right now is trying to accellerate a test article to high enough speeds. Very often, they stick a test article on a sounding rocket that sends back data during re-entry.
And yes, IAARS.
science is a religion
The long-term expensive part about space is not sending equipment up. It is the costs of fuel, water, air, and food i.e. consumables. Fuel and Water can all withstand the high Gs. If this works, the first thing that would make sense is to send all of these up. At that point, you can make the ring pay for a large part of its costs. From there, sats. can be developed that can withstand those forces.
The down fall is that the privatization world will probably be a bit upset about this.
I prefer the "u" in honour as it seems to be missing these days.
I was at a presentation last week by the guys in this article.
The track design is based on particle colliders, so the entire thing is evacuated. Part of it is a rough vacuum and part is a hard vaccum (the actual track). The rough vacuum is because they have to limit thermal transfer to their super-cooled superconducting magnets.
The acceleration is actually not linear- it's radial. Going around a 2km track at 10km/s has some hefty acceleration associated with it. When ejected into the atmosphere, the projectile shouldn't immediately slow a great deal, although it will lose a lot of momentum before leaving the atmosphere. The design is a very long and skinny cone, to reduce thermal heating and drag force.
The best thing about this design for a launcher is that it doesn't require a lot of instantaneous power, unlike a linear accelerator. You can accelerate slowly.
Also, did anyone else immediately think of Xenogears when they saw this?
The gaseous explosion doesn't happen, fortunately. During the Appolo program, a guy in a vaccuum chamber fell down and shattered his face mask - he was very suddenly exposed to total vaccuum. He was consious for a few seconds (say 5-10), and then passed out. It took them another few seconds to bring the chamber back up to atmospheric (say about 20-30 seconds). He was resuscitated, and had no long term injuries from the experience.
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