# Tag Info

14

I've been wondering this for years, not knowing how to approach the problem. Then at a NasaSpaceFlight thread a poster who calls him(her?)self R7 told me about dynamic pressure, also known as q. $q=.5*\rho*v^2$ q is measured in pascals. R7 told me the expression Max-Q is the maximum dynamic pressure a space craft endures during it's flight. Page 109 of ...

14

It’s an interesting idea, but the problem will be accuracy. Depending on the conditions found on the ground, it might be difficult to produce uniform “ammunition” and an “engine” with a sufficiently reproducible throw. The catcher would also have to be a substantial structure capable of dealing with significant wear. I would use a cable car / chairlift ...

11

I'm not sure if a thrower-catcher system is a good solution. Some points: Getting a canon (or launcher of any sort) to fire accurately across four kilometers without precision machined shots or a guidance system is going to be very, very difficult. Especially considering the lack of atmosphere which makes aerodynamic flight stability and control infeasible, ...

7

Short answer: Yes. Big. Long answer: There's no law that says this technology doesn't scale. Railguns functionality is dead simple. You apply a current to two rails and bridge across which produces a large perpendicular force with magnetic fields. The reason I originally voted to close this question was because asking if something is feasible is pretty ...

4

You could build a much safer, if less dramatic, system by transporting slugs of ice through 4.5 km of thin-wall flexible tubing in the manner of a pneumatic mail tube. If you have water ice, both hydrogen and oxygen are available through electrolysis to use as the working gas. Use whichever gas works better. If you can build such a system using two tubes -- ...

3

The showstopper for Earth launch is the atmosphere. Drag grows proportional to velocity squared, so materials accelerated up to several km/s are going to slow down very quickly. Each doubling of velocity is only going to give you the same amount of extra jet range as the previous doubling. This is a very efficient ceiling for how fast things can go inside ...

2

The potential of a horizontal launch within the earth's atmosphere is very much limited by the atmosphere itself. At a low height the maximum speed is limited by the high atmospheric pressure and at medium height there is not enough oxygen left for the scramjet. But to get into a low orbit, much more speed and height is necessary, about 8 km/s speed instead ...

2

Gerald Bull's work on Project Babylon in the late 1980s was very promising and it seems likely that his system could have worked to get payloads into orbit. His systems were essentially very large conventional artillery pieces. He was assassinated in 1990. This has somewhat discouraged further research into this area.

2

The general concept of leaving all the heavy parts of a launcher have been investigated several times and the notes here remain relevant. The actual firing into space is quite possible, the difficulty is that space is more than just going up, you also need 7kms sideways velocity so being fired to 200km straight up still leaves you needing most of the rocket ...

2

I can see 2 problems with your idea. First of all, if the object leaves the mass driver with anything like orbital speed, the driver had better be located very high. Otherwise, the payload will burn up as soon as it exits into the atmosphere. Note that I'm assuming the driver tube is kept in vacuum; if it isn't, atmospheric friction will destroy the payload ...

2

You're going at this the wrong way. What you are showing is meant for mobile use. That means it runs at very high power densities and you're going to get some nasty scaling problems due to the square-cube law. I would consider your mission probably impossible because of this. Your requirement to float is almost certainly impossible--given the extreme ...

1

If you launch a lump of metal from Earth's surface, then after less than or equal to one orbit it will re-intersect the surface of Earth. This is obviously the end for it. Therefore any gun proposal to launch into orbit must have a way of applying a force to the object well after it has left the gun in order to circularize the orbit. Quicklaunch solved ...

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