If this has been asked before I apologize…but…
Why can’t we shoot a satellite into space using some sort of accellerant and ( for lack of a better word) gun. Whether it be gun powder or even nuclear power. Besides the obvious gravity problem, what else stands in the way? Survivability of the payload? Or is it that we can’t develop a barrel long enough? Would the detonation be too much for any metal that might be use to construct a gun which would shoot a technological package into space?
If we could…think of the savings.
Of course that’s just my opinion I could be wrong.
Dennis Miller
There’s a few problems with just shooting things off the planet. First is the acceleration you need to do it. If you assume that it all takes place within the barrel length of the “big gun”, the force would be too much for any payload to withstand. If you want to know the exact G force, ask someone from the calculus thread, I barely passed it. Assuming the payload could withstand the force, you’d have to deal with making a “capsule” that could stand the air friction of going someting like 23,000 miles an hour, the escape velocity of th earth. Not yet possible but maybe someday…
Yes, there are people who concieve of a very large cannon as a way of getting non-fragile payloads into space. I don’t think most instrumentation would survive, unless billions were spent making it tough enough to survive, but sturdy things like food and water could probably be put into space one day. The cannon could make use of electromagnetic technology as well, which would get round some of the problems with gunpowder.
Almost, but not quite, because the resulting “orbit” intersects the earth again somewhat later, which is bad.
However, if you do an orbital insertion burn near apogee, you can do it, and greatly reduce how much fuel you need to carry to achieve orbit. So the idea is a good one (save for the practical issues of building such a gun, and that it only works for very hardy payloads). I think some amount of study has gone into the concept.
I remember reading about the late Dr. Gerald Bull, the Canadian expert on high-velocity guns. He met an untimely end, due to the fact that he was a consultant for Saddam hussein (the Israeli Mossad bumped him off).Supposedly, he was working on s supergun that would have launed a projectile up to 500 miles! Has anybody revived interest in these “super guns”?
As was pointed out up thread it is entirely possible to “shoot” something into space, but the acceleration makes it hard on anything fragile.
Most plans for large scale development in space postulate Lunar mining facilities which launch raw materials into space using mass drivers, essentially large electromagnetic guns. Of course they are doing this with rocks from a low gravity location with no atmosphere.
“Drink your coffee! Remember, there are people sleeping in China.”
The Super Gun was indeed real and able to do this. However, as men are, they decided it would be better as a weapon and thats as far as it got. It could indeed send up a satellite carefully.
For any reasonable-sized “gun”, there’s another problem – the air in the barrel. Since the thing has to be way more than supersonic to get to orbit, the air in the barrel won’t get out of the way. At the speeds involved, hitting that air’s like hitting a brick wall, and if you add more explosive, it only gets worse.
A miles-long railgun doesn’t the same problem, since the energy doesn’t have to be built up in one “boom”.
John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams
More on “super guns”. In WWI, the germans had a gun that could lob shells up to 75 miles (the Paris Gun). These were built by Krupp, and very curiously, all of the guns and the blueprints were destroyed by Krupp after the armistice. Dr. Bull was able to launch modified artillery shells up to altitudes of 12 miles. Too bad he got wasted!
There have been several proposals to use earth-based railguns or mass drivers to help get payloads into orbit. You don’t have to launch them all the way to orbit - if you can get them even 18,000 ft up, you’ve put them above half of the Earth’s atmosphere, and a secondary rocket fired from there would use a lot less fuel to achieve orbit. A rocket launched from the ground uses up a high percentage of its fuel by the time its a few thousand feet above the ground, because it needs more fuel to lift the fuel it needs, etc. If you can find a way to avoid even just the first phase of a rocket launch, you can save a ton of money.
dhanson, but we aren’t talking about rockets but about big cannons that can shoot. Most important about them is the barrel has to be very long, extremely long & this allows the pressure to do it’s work.
During WW2 , radar-fused anti-aircraft shells were used. These shells used a proximity fuse that generally operated on the same principle as radar. They used (obviously) vacuum-tube technology. If glass vacuum tubes could be built in the 1940’s, I fail to see the difficulty in building the neccessary technology today. It is quite possibly “off the shelf” gear; & should easily be able to survive the “spacegun” being fired.
“Show me a sane man, and I will cure him for you.”----Jung
I believe the first “supergun” was the WW1 Paris Gun mentioned above. According to my huge book on weapons of war, it was mounted on a railroad car. In WW2, the Germans tried to build a battery of 50 guns in Normandy, France that could shell London. The max rate of fire was projected to be something like 800 shells per hour! Joseph Kennedy was killed in a pre-emptive bombing raid on these guns. Half of them were destroyed, and repairs and technical problems stalled completion of the other half until after D-day. As for Saddam’s superguns, I suppose he wanted them as a sort of poor man’s cruise missle. Does anyone know if he ever shot any of them? If he did, I assume that either Saudi Arabia or Israel was the target.
“I had a feeling that in Hell there would be mushrooms.” -The Secret of Monkey Island
These shells were only fired at a velocity that would take them, say, 4 or 5 miles high (where the enemy planes were). The velocity needed to send a shell 100 miles high and into orbit would be many times faster (hence many time more damaging to instrumentation.)
The problem with a super-cannon is that the propulsive energy is expended in the very first fractions of a second after the explosive has, well, exploded. The incredible amount of thrust needed to achieve escape velocity would produce g-forces that would destroy most satellite components.
As several posters have pointed out, a rail-gun would be able to launch an object into space. Since the acceleration is produced over a longer period of time (the lenth of the rail), the g-forces would not be quite as extreme. I wouldn’t recommend using it for a manned mission, but you could shoot raw materials into space and have them captured by a waiting craft.
I’ve read some speculative articles that suggest building a rail gun on the Moon, and use that to launch material mined from the Moon towards Earth. You’d have to perform some tricky calculations, but it would be an interesting way to get raw materials from the Moon to the Earth. Of course, it would also be the mother of all weapons, should the lunar colonists ever decide to attack Mother Earth…
Guy, the moon based railgun would be probably fixed to fire at one of the Lagrange points or similar, and then the material redirected towards earth, is cheaper I believe.
There is a group that has designed a prototype rocket that will be launched via a railgun/similar device, and then will fuel up using a KC-130 aircraft at 35000 feet to do the final assent to to LEO.
Also, one of the groups going for the LEO prize (I believe $100,000 for first amatures to put rocket into LEO) is using several weather ballons to lift the rocket to high altitude before launch. I also believe most think they will be the winners of the prize.
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