Single Stage to Orbit Vehicle

[penlu]

A single stage to orbit vehicle is really difficult. I think that if the fuel tanks were combustible, the vehicle could become single stage to orbit. Right?

 

[Deke]

A single stage to orbit vehicle is really difficult. I think that if the fuel tanks were combustible, the vehicle could become single stage to orbit. Right?

You mean like, a single booster + payload? Or all one spacecraft with no seperations during launch?

 

[Jarvitä]

A single stage to orbit vehicle is really difficult. I think that if the fuel tanks were combustible, the vehicle could become single stage to orbit. Right?

What? If it has more than one stage, it's not a "single stage" vehicle, no matter what kind of fuel tanks you put into it. With that said, the tanks for liquid hydrogen have to insulate it to prevent it from warming up too much, so they couldn't really be made "combustible" unless you want to count their disintegration upon atmospheric re-entry as a combustion.

 

[Andy44]

Combustible fuel tanks is actuall a neat idea, I think. Kind of like caseless rifle cartridges, hmm? It'd be hard to make it work, though.

 

[Eagle]

SSTO vehicles aren't easy, but definitely possible. The old Atlas that launched the Mercury Spacecraft was almost a SSTO. The Atlas dropped 2 of its engines during launch to reduce weight (Officially a 1.5 stage rocket), but the rest of the rocket made it to orbit.

And this was back in 1957!

 

[SiberianTiger]

It's easier to imagine something like this with a solid rocket than a liquid: a solid fuel that is a containment for itself. The only problem is what's the nozzle might be made of.

 

[penlu]

No, nothing is dropped. The empty fuel tanks would be burned as solid fuel. But it's true that it would be hard to keep the oxygen tanks from burning 0_o.

 

[Urwumpe]

You can't combust pressurized tanks (and even more pressure on solid rocket motors) past a point. That is a limitation you can't avoid. Some structural mass will be inevitable. This pressure does also not drop when you consume fuel.

You can reduce mass by using less pressure in the tanks, but this requires you more complex propellant management systems, as well as more complex engines.

The best way into orbit is no SSTO, but IMHO, a reusable two stage rocket. You can do that with existing technology, it just requires R&D costs to reduce or manage complexity.

 

[C3PO]

The best way into orbit is no SSTO, but IMHO, a reusable two stage rocket. You can do that with existing technology, it just requires R&D costs to reduce or manage complexity.

I agree. Well, sort of.

For heavy payloads, a two stage is the way to go IMHO.

But I believe that manned flight should be separated from the heavy launches. Or put another way, manned surface --> LEO --> surface should be a system separate from the rest.
This way you would get enough flights to:
A: Bring the cost down
B: Get out of the prototype stage (more flight history, experience, data etc.)

The ascent and reentry requirements are very specialized, and most of the equipment will be 'dead weight' during the mission (wings, shield, landing system).
I particularly like the White Knight type air launch, and I hope that SSCRAM engines will "take off" :lol:

 

[Andy44]

SSTO vehicles aren't easy, but definitely possible. The old Atlas that launched the Mercury Spacecraft was almost a SSTO. The Atlas dropped 2 of its engines during launch to reduce weight (Officially a 1.5 stage rocket), but the rest of the rocket made it to orbit.

And this was back in 1957!

The Space Shuttle is also a stage and a half, as all engines are ignited on the pad and some of them drop off at SRB sep. But this is nowhere near being "almost SSTO", unless you replace the orbiter with something a lot smaller and lighter.

 

[Kaito]

Instead of launching straight up and having to fight gravity indefinitely, get a smaller shuttle, and use a magnetic launch system. Angle it east, angle it up, and launch it. We already have rail guns (guns that use a magnetic launch system (basically, the projectile rides a magnetic "wave")), and if combined with a decent engine, it could probably get us into space.

Problem: Rail guns take A LOT of power. According to wikipedia, "As of February 2008, the largest known energy ever used in a railgun was 32 million joules." So, they are big, need TONS of energy, generate heat, etc, etc, etc.

I know that we launch straight up to leave the atmosphere quickly, but if we want SSTO, we need to not fight gravity indefinitely.

~Kaito

 

[John_L]

To get true SSTO craft, you need a different rocket engine, such as the aerospike engines that were being developed for the now defunct Venture Star...

 

[cjp]

I don't think that burning your fuel tanks will solve anything. As soon as holes start appearing in the sides, exhaust material will escape in the wrong places, so in the best case it won't give you any thrust, and in the worst case it will make your rocket spin around. You might as well throw away the empty fuel tank, as the space shuttle does.

Besides, you can wonder whether SSTO is an interesting goal. Suppose you manage to make a SSTO vehicle. With current technology, it will bring itself into LEO, and a very small amount of payload. Bringing your payload to LEO is what you want, but bringing the rocket to LEO is useless, unless you can bring it back to earth and re-use it. If you can't re-use it, you might as well make it multi-stage to make it more efficient. So SSTO is only interesting if it can be re-used. And even then you can wonder whether it will be cheaper in the end than re-usable multi-stage, or non-reusable concepts.

I like the idea of having a magnetic catapult as first stage. I've recently been to Shanghai, where they have this German maglev train :speakcool:. They use it up to 420 km/h (unfortunately, when I used it, it "only" did 300 km/h), but I guess you can easily boost it to above 600 km/h. Then a ramjet might be a nice in-atmosphere second stage, up to maybe mach 5 or 6? I guess you can do the rest with rockets.
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[thomasantony]

Maybe they can make a humoungously long rail gun tracks in some desert like Mojave. Accelerate the craft to enough velocities to use Ram Jets, then fire them up and take off!! . No turbines.

 

[Eagle]

I think about the only way to burn your fuel tanks is to either have a giant stick of solid fuel and have your engine burn it from the bottom up as it travels forward. Kind of like candles with those glass things on the top that push the sides in as it burns down.

You could do it other ways where you crumple and burn the fuel tanks, but those are probably less effective.

 

[Kaito]

So SSTO is only interesting if it can be re-used. And even then you can wonder whether it will be cheaper in the end than re-usable multi-stage, or non-reusable concepts.
​

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It would be reusable. When thinking of SSTO, think of the Delta Glider.

 

[Urwumpe]

[/left]
It would be reusable. When thinking of SSTO, think of the Delta Glider.

The Deltaglider ist NOT realistic. When the engines would be running, they would evaporate the spaceport. I think somebody once made the effort calculating the chamber pressure of this monster.

 

[Kaito]

i know the DG isn't realistic. Its just an example of SSTO

 

[Urwumpe]

i know the DG isn't realistic. Its just an example of SSTO

Yes. And it only works by unobtainium. You can't plan with such a thing existing soon like that one.

 

[Linguofreak]

Instead of launching straight up and having to fight gravity indefinitely, get a smaller shuttle, and use a magnetic launch system. Angle it east, angle it up, and launch it. We already have rail guns (guns that use a magnetic launch system (basically, the projectile rides a magnetic "wave")), and if combined with a decent engine, it could probably get us into space.

Problem: Rail guns take A LOT of power. According to wikipedia, "As of February 2008, the largest known energy ever used in a railgun was 32 million joules." So, they are big, need TONS of energy, generate heat, etc, etc, etc.

I know that we launch straight up to leave the atmosphere quickly, but if we want SSTO, we need to not fight gravity indefinitely.

~Kaito

Another problem: You can't launch live humans on a railgun. The acceleration involved would reduce any live payload to strawberry jam.