Posted: 11/15/2012 10:45:19 AM EDT
| I realize they'd have to be BIG balloons, but it seems to me that if you can put a small "capsule" at 128,000 feet with a single balloon, you could rig up something bigger to carry a small ship that high. How much less fuel would you need if you could eliminate the first 120,000 feet of vertical thrust requirement? And how much smaller could a launch vehicle be as a result? |
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I realize they'd have to be BIG balloons, but it seems to me that if you can put a small "capsule" at 128,000 feet with a single balloon, you could rig up something bigger to carry a small ship that high. How much less fuel would you need if you could eliminate the first 120,000 feet of vertical thrust requirement? And how much smaller could a launch vehicle be as a result? It's not the altitude, it's the delta-V. Getting to ungodly high altitude isn't terribly hard (SpaceShipOne gets to 328,000 feet with a fairly small fuel fraction) it's getting to orbital velocity (17,600 ish mph). There are airborne launch platforms (Pegasus) but there are diminishing returns. |
| I'm not a Rocket Surgeon, and I didn't stay at a Holiday Inn last night, but it seems to me that you have not considered escape velocity. If your launch vehicle was at maximum altitude at launch, how far would it fall before the propulsion would overcome gravity and the vehicle would start climbing again? And what would happen if Wiley Coyote ran out of matches before he could light the fuse? |
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Quoted: I realize they'd have to be BIG balloons, but it seems to me that if you can put a small "capsule" at 128,000 feet with a single balloon, you could rig up something bigger to carry a small ship that high. How much less fuel would you need if you could eliminate the first 120,000 feet of vertical thrust requirement? And how much smaller could a launch vehicle be as a result? At altitude, the RedBull balloon had a capacity of about 30 million cubic feet. The capsule/man combination weighed about 1.5 tons. That's less than the weight of the balloon itself. The sizes that would be needed to lift small ships border on the absurd. And you sacrifice nearly all navigation, guidance, and other precision aspects typically essential to orbital missions. NASA has been working with balloons to lift smaller instrument packages. I believe they must occur from a limited launch window in Antarctica though. |
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I realize they'd have to be BIG balloons, but it seems to me that if you can put a small "capsule" at 128,000 feet with a single balloon, you could rig up something bigger to carry a small ship that high. How much less fuel would you need if you could eliminate the first 120,000 feet of vertical thrust requirement? And how much smaller could a launch vehicle be as a result? 25% less fuel. That's a NASA number, not something I just pulled out of my ass. It's just not feasible for large launches, but for satellites under about 2 pounds, it could be a decent idea. A gas gun would probably be more reliable. |
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I realize they'd have to be BIG balloons, but it seems to me that if you can put a small "capsule" at 128,000 feet with a single balloon, you could rig up something bigger to carry a small ship that high. How much less fuel would you need if you could eliminate the first 120,000 feet of vertical thrust requirement? And how much smaller could a launch vehicle be as a result? 25% less fuel. That's a NASA number, not something I just pulled out of my ass. It's just not feasible for large launches, but for satellites under about 2 pounds, it could be a decent idea. A gas gun would probably be more reliable. Yeah if i remember correctly its not so much the height as it is getting the object up to orbital speed. IIRC if your not doing ~17,000 mph when you get to your orbit, your coming back down. I remember reading an article about a big gas gun quite a few years ago that was looking to launch non-G sensitive items into orbit, think food, raw materials, pretty much anything that isn't going to be damaged by being accelerated to 30,000 mph in 1/4 of a mile. |
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Somewhere around 50 years ago I used to enjoy a TV show called Watch Mr. Wizard. One of the cool parts was kids making their own devices and demonstrating them on the show. One kid made a sled that was pulled down some rails by electromagnets. A simple wheel was rotated to change which set of magnets was powered. He had the rail curve up to an almost vertical position at the end. With a simple crank of the wheel he powered the sled down the rails and launched it a few feet into the air.
His theory was that in using the electromagnets to overcome inertia, you could cut down the amount of fuel needed to launch a rocket by somewhere near 50%. This would allow larger payloads on smaller rockets. It sure makes sense to me. Huge cost savings. |
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I realize they'd have to be BIG balloons, but it seems to me that if you can put a small "capsule" at 128,000 feet with a single balloon, you could rig up something bigger to carry a small ship that high. How much less fuel would you need if you could eliminate the first 120,000 feet of vertical thrust requirement? And how much smaller could a launch vehicle be as a result? 25% less fuel. That's a NASA number, not something I just pulled out of my ass. It's just not feasible for large launches, but for satellites under about 2 pounds, it could be a decent idea. A gas gun would probably be more reliable. Yeah if i remember correctly its not so much the height as it is getting the object up to orbital speed. IIRC if your not doing ~17,000 mph when you get to your orbit, your coming back down. I remember reading an article about a big gas gun quite a few years ago that was looking to launch non-G sensitive items into orbit, think food, raw materials, pretty much anything that isn't going to be damaged by being accelerated to 30,000 mph in 1/4 of a mile. SHARP is the gun your thinking about, it was the successor to the HARP gun (not the weather controlling HAARP  ) that was 2 16" battleship barrels welded together. HARP was led by Gerald Bull, the guy who later designed the Babylon gun for Saddam.
Quicklaunch is a company that wants to make a larger version of the SHARP gun, and use it to create a fuel depot in space. Not having to launch all your fuel with a normal rocket would have a huge effect on any mission beyond LEO, you could have a larger spacecraft, or use a smaller rocket to launch your spacecraft. The saving on getting the fuel into orbit would be huge as well. |