Is it possible to launch a rocket from a balloon?
The launch components will get very cold, is there a way to keep the rocket in good condition for ignition and blastoff?
We could use a hybrid airship as a reusable launch shuttle....
Put the platform between two airships as a pad
or four airships
0 X 0
X = Launch pad
Hybrids act as a wing AND a balloon
I need to correct myself before someone else does - it wouldn't take the same amount of fuel, it would be a bit less because you wouldn't have to fight against gravity and most of the air resistance. But you'd still have to carry up the majority of it
Orbital speed is still the same regardless, it only depends on the height you're orbiting at. You can calculate the amount of fuel you'd need using the Tsiolkovsky rocket equation. If your rocket is starting from the ground, then you have to account for the effects of air resistance and gravity drag by using a bit more fuel
During 2002 an ultra-thin-film balloon named BU60-1 made of polyethylene film 3.4 µm thick with a volume of 60,000 m3 was launched from Sanriku Balloon Center at Ofunato City, Iwate in Japan at 6:35 on May 23, 2002. The balloon ascended at a speed of 260 m per minute and successfully reached the altitude of 53.0 km (173,900 ft), breaking the previous world record set during 1972
As the other anon said, only up to the top of the atmosphere with a balloon. You might be interested in the idea of a space elevator if you haven't heard of it, that would be able to lift something all the way into orbit without using a rocket at all. It's also a good meme topic
For getting into orbit its speed you want not altitude. The ISS goes more than 7 km per second. A balloon will not going take you anywhere resembling a significant fraction of that speed. It does however loft you above most of the atmosphere so there's less drag once you actually start going.
Keeping the rocket's components at proper temperature shouldn't be that difficult. Many space rockets use cryogenic propellants, remember?
And several smaller rockets actually have been launched from balloons, and the USAF test-launched an ICBM from a parachute which would probably be quite similar.
You still have to fight against gravity, but since air drag isn't penalizing you so much you can get away with higher acceleration which reduces the cost of gravity drag.
And another factor you failed to mention was air pressure - rockets achieve better specific impulse in near vacuum than in atmospheric pressure.
In either case, decreasing ambient pressure is going to improve specific impulse. Even a nozzle designed for sea level operation will still perform better in vacuum - just not as well as one designed to work in a vacuum.
For the money required to build a jet that can reach as high as a balloon you may as well spend it on an extra booster
This is the kind of stuff I've thought of too but unvortunately I think it's another case of it if was such a great idea others would be doing it. The big problem is that balloons can lift hardly anything, it would have to be vast to be able to lift a rocket big enough to reach orbital velocity, may as well just use an extra booster. An idea that really needs more attention however is the "big dumb booster" concept. A company back in the 70s successfully did launches with cheap as fuck solid boosters lashed together but it got shut down because the powers that be didn't want cheap ballistic missiles floating around. In short, big ass boosters are the only way to go.
Okay so lets assume the best
You get a space train to 50 km above the surface.
Then you load your rocket in said space train and fire....
A projected naval rail gun with a 2.5km/sec muzzle velocity...shit...you could be on to something.....could deliver a guided projectile with an impact velocity of Mach 5 to targets at ranges of 250 miles........
It just isn't worth the extra weight (inb4 gaben). It ends up being more fuel-efficient to have a fixed nozzle. Fighter jet engines tend to have variable nozzle areas, since fuel efficiency and cost aren't as important as pure performance.
What's going to happen to a launch platform suspended by a balloon when it's bombarded by gas escaping from the nozzle of a rocket? We launch then from solid ground for a reason. That rocket is going to destabilize the platform, fall off the platform, accelerate towards the ground, and kill lots of people.
Because then you have to get to the moon first. That kind of thing has been suggested though - get your payload to the moon, and then launch it using a rocket+fuel or railgun that was manufactured on the moon itself. (Hundreds of years beyond our reach of course)