# What is the highest a projectile has been thrown or fired from ground level on earth?

Anyway from here:-
http://www.astronautix.com/stages/harpgun.htm

250 kg projectile accelerated at 13,000 peak G's to 2,300 m/s muzzle velocity

This 2,300 m/s is the fastest muzzle velocity I can find.

Anyhow those seem like the sort of speeds at which you will have serious heat problems perhaps, maybe also that is why the stopped the project.

Furthermore it seems this is not actually a gun at all!!

It seems like it fires a rocket.

As you can see here it seems to be a gun fired rocket, which is ineligible!!

http://www.astronautix.com/articles/abroject.htm

The altitude reported earlier of about 180km is wrong as it is no applicable to a gun.

DaveC426913
Gold Member

Furthermore it seems this is not actually a gun at all!!

It seems like it fires a rocket.

As you can see here it seems to be a gun fired rocket, which is ineligible!!

I wondered that too. No. They're just ballistic missiles.

So I expect it is possible to calculate a pretty much maximum possible height because I believe there comes a point at which the projectile is going to melt in the barrel with probably rather unpleasant consequences!!

That was kind of the whole point of the initial thread.

So I think some of the comments aimed at me have been rather unfair.

DaveC426913
Gold Member

So I expect it is possible to calculate a pretty much maximum possible height because I believe there comes a point at which the projectile is going to melt in the barrel with probably rather unpleasant consequences!!

That was kind of the whole point of the initial thread.

Except that that's simply an engineering problem. It is simply a matter of someone being clever enough to tinker with it until it goes faster.

For example, who needs a barrel at all?

("simply". Ha ha. The engineers are strangling themselves right now.)

Except that that's simply an engineering problem. It is simply a matter of someone being clever enough to tinker with it until it goes faster.

For example, who needs a barrel at all?

("simply". Ha ha. The engineers are strangling themselves right now.)

Well the problem seems to be that it needs to be fired at such a speed that projectile will burn up. That will it seems happen whether you have a barrel or not.

One way round it would be to use a bigger projectile or there would be something left after the melt but that just seems to scale up the problem.

I just can't see it being possible to escape earth's gravity whatever method you use.

Getting rid of the barrel would create more problems than it solves I would imagine.

Aw come on guys, the bullet fired from yuma was a small aluminum slug in a sabot. At least that was the final stage, the gun holds the record for shooting from the ground onto space whatever the distance was. see HARP

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SpectraCat

Anyway from here:-
http://www.astronautix.com/stages/harpgun.htm

250 kg projectile accelerated at 13,000 peak G's to 2,300 m/s muzzle velocity

This 2,300 m/s is the fastest muzzle velocity I can find.

Anyhow those seem like the sort of speeds at which you will have serious heat problems perhaps, maybe also that is why the stopped the project.

Furthermore it seems this is not actually a gun at all!!

It seems like it fires a rocket.

As you can see here it seems to be a gun fired rocket, which is ineligible!!

http://www.astronautix.com/articles/abroject.htm

The altitude reported earlier of about 180km is wrong as it is no applicable to a gun.

From the HARP page on wikipedia:
"HARP used a non-rocket spacelaunch method based on a very large gun to fire the models to high altitudes and speeds."

And

"The project was based on a flight range of the Seawell Airport in Barbados, from which shells were fired eastward toward the Atlantic Ocean. Using an old U.S. Navy 16 inch (406 mm) 50 caliber gun (20 m), later extended to 100 caliber (40 m), the team was able to fire a 180 kilogram slug at 3,600 meters per second (13,000 km/h), reaching an altitude of 180 kilometers. "

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We have been through all this before you need to define stuff for these sorts of questions.

Modify the LHC a bit and you could definitely fire a big clump of protons out of the planet at 99% the speed of light but are a clump of protons considered a projectile in your definition.

The protons would not get very far IMO the they would disperse in the atmosphere fairly rapidly.

QuantumPion
Gold Member

Possibly during http://en.wikipedia.org/wiki/Operation_Plumbbob" [Broken]:

During the Pascal-B nuclear test, a heavy (900 kg) steel plate cap (a piece of armor plate) was blasted off the top of a test shaft at an unknown speed. The test's experimental designer Dr. Brownlee had performed a highly approximate calculation that suggested that the nuclear explosion, combined with the specific design of the shaft, would accelerate the plate to six times escape velocity. The plate was never found, but Dr. Brownlee believes that the plate never left the atmosphere (it may even have been vaporized by compression heating of the atmosphere due to its high speed). The calculated velocity was sufficiently interesting that the crew trained a high-speed camera on the plate, which unfortunately only appeared in one frame, but this nevertheless gave a very high lower bound for the speed. After the event, Dr. Robert R. Brownlee described the best estimate of the cover's speed from the photographic evidence as "going like a bat!"

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DaveC426913
Gold Member

Possibly during http://en.wikipedia.org/wiki/Operation_Plumbbob" [Broken]:

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Hmmm.... might explain that gash on the moon appearing right afterwards ))

Surely it is fairly simple to calculate the heat generate on a projectile "of minimum heat generation" at the required 'launch speed'?
I expect such a calculation who save them building a lot of expensive guns!!

I am not sure how to go about the calculation myself, ie the heating effect at various speeds, there must be some sort of equation knocking about somewhere?

I mean we see the massive problems with the re-enter of the space shuttle, the heat generated here must be an order of magnitude above that, surely!?

http://en.wikipedia.org/wiki/Electromagnetic_gun" [Broken] about rail guns says: the U.S. Navy has tested a railgun that accelerates a 3.2 kg (7 pound) projectile to approximately 2.4 kilometres per second (5,400 mph). It also talks about current research to use this technology to launch things into orbit. For this application it states that the muzzle velocity would be 7.5 km/s

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