John Hunter wants to shoot stuff into space with a 3,600-foot gun. And he's dead serious—he's done the math. Making deliveries to an orbital outpost on a rocket costs $5,000 per pound, but using a space gun would cost just $250 per pound.
Building colossal guns has been Hunter's pet project since 1992, when, while a physicist at Lawrence Livermore National Laboratory, he first fired a 425-foot gun he built to test-launch hypersonic engines. Its methane-driven piston compressed hydrogen gas, which then expanded up the barrel to shoot a projectile. Mechanical firing can fail, however, so when Hunter's company, Quicklaunch, released its plans last fall, it swapped the piston for a combustor that burns natural gas. Heat the hydrogen in a confined space and it should build up enough pressure to send a half-ton payload into the sky at 13,000 mph.
Hunter wants to operate the gun, the "Quicklauncher," in the ocean near the equator, where the Earth's fast rotation will help slingshot objects into space. A floating cannon—dipping 1,600 feet below sea level and steadied by a ballast system—would let operators swivel it for different orbits. Next month, Hunter will test a functional, 10-foot prototype in a water tank. He says a full-size launcher could be ready in seven years, provided the company can round up the $500 million. Despite the upfront cost, Hunter says he has drawn interest from investors because his reusable gun saves so much cash in the long haul. Just don't ever expect a ride in the thing: The gun produces 5,000 Gs, so it's only for fuel tanks and ruggedized satellites. "A person shot out of it would probably get compressed to half their size," Hunter says. "It'd be over real quick."
How to Shoot Stuff into Space
STEP 1: HEAT IT
The gun combusts natural gas in a heat exchanger within a
chamber of hydrogen gas, heating the hydrogen to 2,600˚F and causing a 500 percent increase in pressure.
STEP 2: LET THE HYDROGEN LOOSE
Operators open the valve, and the hot, pressurized hydrogen quickly expands down the tube, pushing the payload forward.
STEP 3: TO INFINITY AND BEYOND
After speeding down the 3,300-foot-long barrel, the projectile shoots out of the gun at 13,000 mph. An iris at the end of the gun closes, capturing the hydrogen gas to use again.
I like the idea. Will the projectile be able to control itself once in orbit? How can it be retrieved. Also, what is the range of this gun? Will it shoot its projectile far enough to retain orbit until it can be retrieved?
I like the writing in this article. Much more scientific based and a whole lot less opinionated than most articles on PopSci have become.
Applaud Amina Elahi
I suppose this issue might apply to rockets too, but is there a chance the eventual orbit of the payload might be affected if it hit a seagull on its way to space?
Interesting news: WIN
Not using SI units in a science article: FAIL
@Mikron i agree
500% increase in pressure? That's only an increase of five times. Doesn't seem like a lot for a shot to orbit.
I'm a little confused... if he were firing an object from the surface of Earth to go into space, wouldn't he have to get the object to reach the escape velocity from the surface? My understanding was that any object fired from the surface would require a speed of 11.2 km/s (25,000 mph) unless it has a system of propulsion to counteract the acceleration (or deceleration in this case) of gravity. How can he fire it off at only 13,000 mph? Does being at the equator really help that much, or am I just missing some basic physics here?
Just missing some basic physics...
11.2 km/s is what you need if you want to escape the earth gravity all together without no danger of falling back ever again. No orbit, that is. The equator gives you an extra 2 km/s for free, compared to firing from the poles.
463 m/s = 40 000 km/24h (more or less...)
"extra 0.463 km/s for free,"
Just playing devil's advocate here...any investigation into possible effects of sonic impulse or recoil on marine life?
Okay, if you don't want your payload flattened, this is the way to go. (apologies for non-SI units throughout). Let's look at a constant acceleration model to see what the g-force would be on this fateful trip:
Length of cannon=3300ft
Final velocity=13000 mph=19066 ft/s
V_f = 2*D/T
Therefore time to escape cannon=.3461 s
A=2*D/T^2 = 55098 ft/sec^2 = (drumroll) 1721 G
Holy cow! Not even cockroaches can survive a tenth of that force.
2 ways why this is impractical/impossible:
1)Building and designing a satellite would be a nightmare. Even if this does work, the structural integrity to overcome the g-loading at launch would add so much weight to the satellite, that it would keep requiring for the power to launch to increase, in result, would require you to increase the strength of the satellite...then you have a never ending loop. Part two of this problem, the instruments on the satellite would also have a requirement to over come the launch g-loading, unless your launching rocks, sounds impractical and extremely expensive. The cost of building and designing the thing would be more than to launch it.
2) In order to launch something into space from the ground economically, the object has to lose mass, or be launched at a higher altitude. Such as the rocket, you burn fuel, drop fuel tanks, etc...basic physics you can find in wikipedia for "escape velocity". And just like jelam04 stated, this thing isn't going anywhere but back down unless it can reach 25,000 mph. Oh and we're not even considering air drag!! At that speed,near ground level, the launch package would hit dynamic q and wouldn't be able to accelerate enough to reach escape velocity.
This would at best be a good warhead launcher.
dfs2010, who cares? It makes a big boom...only downfall it doesn't have boobs or bacon!
also, hope this thing is attached to the bottom of the sea floor, ocean currents can really mess up a launch. Also the moment that the launch would create, I imagine would rock the platform quite a bit (it is essentially a huge unconstrained gun), and by the time the payload is out of the tube, it would be on an altered trajectory.
You do not need to accelerate an object to escape velocity in order to put it into closed orbit. You need to reach just first cosmic velocity which is about 13000 mph. Escape velocity is necessary if you need to escape the Earth gravity, or put an object into unclosed orbit (go into outer space).
If you check out the companies website they have a video of John Hunter presenting his pitch to Google.
Goal muzzle velocities around 6-7.6km/s
gun length 1100m
payloads are multistage (shot out and then use rocket)
used mostly for supplies
they built a satellite for $40k with COTS that could survive 3200gs with only 2% mass increase (doubt it had much sensitive equipment)
Interesting development and another possible contender for private sector space missions.
Super guns to fire projectiles into low Earth orbit are not a new idea. (Saddam Hussein tried to build one for military purposes and its history goes back even further than that.) But building a sea-based gun is very innovative. Aside from mobility, it allows for easy loading while on the surface before submerging the rear-end to the optimal depth. Unlike land-based super guns, it also allows for flexibility in angle orientation. I'm sure that utilizing all that pressure a couple of thousand feet below the surface would be useful as well.
projectile is multistage (shot out the gun and then single stage rocket)
I suppose this cannon placed inside a ship would negate any effects of ocean current and dampen the effects upon sea life, plus the ship would be used to deliver and point the cannon too.
One cargo that would easily withstand the high Gs of launch would be Carbon Nano Tube, the stuff the space elevator cable will be made!
I doubt it would be used much for satellites, but fuel could easily be loaded, and that is very valuable.
Hmm more interesting is the ability make this ship or sub deploy-able. Rounds on target almost anywhere in the world in 40 minutes. This would create a low cost alternative to missile systems. I for one am not sure how I feel about the idea of creating a "low tech" alternative to ICMB's. Lets be honest folks if a guy like me sitting at home see this and instantly thinks that then I am sure there are people in other less stable and friendly places that are thinking the same thing.
OH I would like to add that a weapon of this sort would get by most of the Major powers missile threat detection system as there would be no missile launch to detect and a warhead fired from a weapon like this would most likely be dismissed until to late due to its size on radar when it was detected.
The projectile must be able to maneuver in orbit. Otherwise it will re-enter on the second half of the same orbit it was launched into.
Doubt it will work. At sea level at the kind of speeds they are talking, atmospheric drag will be extreme, causing de-acceleration and heat. Underwater has advantages but also big disadvantages. It might be better to build a longer large bore unit up the side of a mountain so as to have just first stage performance with lower barrel exit velocity.
Still, it can be used to send basic raw materials into orbit, to be captured by some already-existing station there that was launched by conventional means.
With a cheap means of getting raw materials into orbit, I'll really be looking forward to seeing orbital shipyards. Hopefully by then fusion would be advanced enough to power rugged high-capacity ion drives.
HA. Who am I kidding, we're never gonna get that far :(
I agree with richiej615.
lnwolf41 No one said anything about stable orbit or escaped velocity. They said shoot into orbit, where it could be retrieved by some type of tug. Also to reduce the sudden impact of hitting the air shoot a laser that would create a vacume at launch time. As for recoil deploy wide baffles along the length of the tube, and a tube within a tube to absorbe and reduce the recoil like shockabsorbers. as for to hard on satilites create a non conductive (slime, oil,liquid) to immerse all the components that would support everything yet would be easy to drain out once the sattilite was recovered prior to insertion to a stable orbit.
lnwolf41 Could it be used as a weapon? yes, just like a car ,plane, envelope in the mail, a rock, baseball bat, molavtoff cocktail. Everything that man/ woman has made or invented can be used as a weapon. So MRDAHUT you have a valid point but not one that says we shouldn't build it.
Now all we need is a sky pipe a modification of the non-geosynchronous sky hook. Only a couple of hundred miles long it would be 100 times smaller then the space tether and done with less ambitious materials than 24,000 miles long nanotubes. Various posts with fuel cells would pump and suck hydrogen up it from a steady fleet of fuel tanker aircraft. It would use that fuel to maintain its own orbit. At 70 miles up a bag would fill with fuel for a spaceship one like vehicle to pick it up and go to geosynchronous orbit, or go the end of the sky pipe and pick up an even bigger bag to go the moon. No rockets necessary, just inflate and build you space station close to earth then inflate the fuel to take it to the Moon and then Mars.
lnwolf41 I agree I'm not saying the project should not proceed. I was merely pointing out that it is an almost instantly deployable weapon system. IF it wasn't thought of now it would have been thought of by some one some where some when. But we need to look at any technology and consider its offensive potential to consider how to counter that threat.
It would be good for launching food and water and fuel into space