Does is possible to launch object into space using only SRB

[Pawelk198604]

From what i knew is possible in KSP, but i wondering does it possible do it possible IRL without staging whatsoever

[astropapi1]

You'd need a big SRB, but I don't see why not.

[Themohawkninja]

I know that some rockets only use solid fuel in reality, so yes it is possible.

[Brotoro]

The Scout launch vehicle use all solid fuel stages, so sure.

[Thaniel]

Well, it is possible to make SRB´s that can be shut down in vacuum, by opening them up in both ends. But good planning, custom filled boosters and balanced payloads, if you atleast allow for detailed orbiatl maneuvers to be done using liquid engines of some sort, then yeah, SRB´s can be used to put cargo into orbit.

[Nibb31]

It depends on the payload and on the orbit that you want. It's highly impractical to use SRBs for upper stage burns, though. You wouldn't have much control over orbital altitude, which would make it stupid to use as an operational launcher.

[Kryten]

It's perfectly possible to use SRBs for precise, planned (e.g. GTO-GSO transfer) orbital maneuvers; the models used are designed so small amounts of fuel can be removed without affecting performance.

[astropapi1]

You wouldn't have much control over orbital altitude, which would make it stupid to use as an operational launcher.

You could get some kind of control over it by using Hybrid rockets:

http://en.wikipedia.org/wiki/Hybrid_rocket

It's either 100% or 0%, but far better than a normal SRB.

[Kerbal01]

The European Vega rocket is all SRB, so's the lockeed Martin rocket, Athena.

[Cheebsta]

SRB Launch Vehicle Wiki

Though, I don't know enough to know if that list is complete or not.

[K^2]

You could get some kind of control over it by using Hybrid rockets:

http://en.wikipedia.org/wiki/Hybrid_rocket

It's either 100% or 0%, but far better than a normal SRB.

You can do gradual thrust control with a hybrid. But then you sacrifice fuel efficiency, so it's not really worth it. With proper TWR, there should not really be a reason to do anything other than full throttle or nothing.

Edit: In fact, from the very page you linked. "Start/stop/restart and throttling are all achievable with appropriate oxidizer control."

Edited July 23, 2013 by K^2

[Fractal_UK]

You don't neccessarily need to use a hybrid rocket, you can get throttle control with a pure SRB rocket by altering the fuel density of the solid rocket fuel, allowing you to predefine a thrust profile for your rocket. It doesn't give you the ability to control your throttle on the fly but it does allow you to vary your throttle throughout your ascent profile as part of a predefined flight plan. Similarly you can make an SRB restartable by altering the design parametres of the solid fuel within the booster such that it burns in two or more sections.

[Captain Sierra]

Back to the main question, can you actually get a rocket in KSP in orbit with just solids? I imagine the orbit won't be pretty but who cares. Can it be done (without exploding, breaking SoI, or aerobraking and as a result, lithobraking)? I know I can do it with a KW mega SRB and a liquid fuel circularization stage (as a probe launcher).

[Kimberly]

SRB Launch Vehicle Wiki

Though, I don't know enough to know if that list is complete or not.

Sorry, I have to go into pedantry mode here. You just linked to an article on Wikipedia. Wikipedia is a particularly well-known example of a wiki, a website that can be edited by the general public. You made it look like you were linking to a wiki devoted entirely to SRB launch vehicles.

[CalculusWarrior]

...a wiki devoted entirely to SRB launch vehicles.

That would be the best wiki ever created. Just imagine... Jeb would have a field day!

[Cheebsta]

Sorry, I have to go into pedantry mode here. You just linked to an article on Wikipedia. Wikipedia is a particularly well-known example of a wiki, a website that can be edited by the general public. You made it look like you were linking to a wiki devoted entirely to SRB launch vehicles.

Yeah, I care about this, cause the link doesn't pop up in your browser without clicking.

[K^2]

Back to the main question, can you actually get a rocket in KSP in orbit with just solids? I imagine the orbit won't be pretty but who cares. Can it be done (without exploding, breaking SoI, or aerobraking and as a result, lithobraking)? I know I can do it with a KW mega SRB and a liquid fuel circularization stage (as a probe launcher).

Yes, it's definitely possible with good timing and staging. You will have to have at least two stages, because while RT-10 does have delta-V reserve that would be sufficient for a good rocket to reach orbit, its TWR is too high to make use of that delta-V reserve efficiently, meaning you wouldn't be able to ride one to orbit. With two stages you can build a craft that has more than sufficient delta-V at whatever TWR you end up with, so what you'll actually end up having to do is turn around at just the right moment and use the remaining SRB fuel of the second stage to slow you down. Then you might have to do a few more flips to make sure you don't overshoot either way. Alternatively, you can build the whole thing to allow it to jettison the second stage boosters once in proper orbit.

I might have to try this. I'll post back if I get anything cool out of it.

P.S. I'd buy a beer for whoever first came up with term "lighobraking".

[Thaniel]

About a year ago or so, there was a challenge regarding this. As far as I can remember, it was get to the mun (and back) using nothing but SRB´s. The winner got to the mun, and back again sucessfully.

[magnemoe]

Well, it is possible to make SRB´s that can be shut down in vacuum, by opening them up in both ends. But good planning, custom filled boosters and balanced payloads, if you atleast allow for detailed orbiatl maneuvers to be done using liquid engines of some sort, then yeah, SRB´s can be used to put cargo into orbit.

Some ICBM has blow out panels to cancel trust of solid state rockets, however not sure you can reach orbit in an single stage solid state rocket, icbm is the closest we have to pure solid state and they has many stages as it don't cost much.

[Nibb31]

The European Vega rocket is all SRB, so's the lockeed Martin rocket, Athena.

You're right about Athena (although it doesn't seem to have been a very successful launcher). Vega uses an liquid upper stage called AVUM, with multiple restart capability, which makes it much more flexible.

The reason the Athena IUS upper stage uses solids, is that it was designed for Shuttle payloads, and liquid upper stages were banned from Shuttle flight rules after Challenger.

The problem with a 100% solid rocket is that you need to perfectly calculate and custom-build your solid upper-stage for the payload and target orbit. Any variation from the nominal trajectory, and your payload ends up in the wrong place. Although it is technically possible, it isn't very practical for a commercial launcher, where throttling and restartability allows more flexibility.

[tomf]

If you wanted a single stage to orbit SRB you need to have it at least 98.5% fuel by mass, which doesn't leave you much mass for payload, casing, controls etc.

mass full/mass empty = e^(delta-v/(ISP*9.8))

The delta-v required for earth orbit is around 10,000 and the ISP of the shuttle SRBs is 245.

[SunJumper]

If you wanted a single stage to orbit SRB you need to have it at least 98.5% fuel by mass, which doesn't leave you much mass for payload, casing, controls etc.

mass full/mass empty = e^(delta-v/(ISP*9.8))

The delta-v required for earth orbit is around 10,000 and the ISP of the shuttle SRBs is 245.

But the delta-v for Kerbin orbit is only 4500 m/s, for a fuel by mass percentage of 84.7%. And that is with the above value for isp.

[softweir]

I am quite sure that a 100% solid rocket could reach orbit, but only if you didn't care which actual orbit it reached. However, most rocket launches are aiming for specific orbits because the customer wants their payload to go "there and not anywhere else, thank you very much!"

It is, in theory, possible to reach a specified orbit with just solid rockets, but only if your theory ignores atmospheric disruption and fuel irregularities. In reality, any and all variations of atmospheric conditions can affect the amount of fuel needed to get to orbit. Humidity increases drag, Increased pressure increases drag. Lower temperature increases drag. Winds can push a rocket off the optimal trajectory, forcing the guidance systems to compensate, causing more fuel to be burnt. Tiny variations in fuel manufacture can affect the ISP of a rocket.

As a result, all launches go up with a few percent of excess fuel, and almost never burn the optimal, intended amount - they either end up with more or less than the predicted fuel excess, and either shut off the engines early or late. Pure SRBs can't safely shut down: there are designs that could open an SRB to vacuum and thus drop internal pressure to below that needed to maintain combustion, but they are dangerous as they are liable to create an uncontrolled failure resulting in shrapnel capable of destroying a payload.

As a result, it is almost certain that any "SRB launch" will in fact have at least an upper stage that is either hybrid SRB or liquid fuel.

[Kryten]

Except scout didn't, athena didn't, and on most launches pegasus doesn't. Not to mention most ICBMs, which while not orbital do require very precise trajectory adjustment.

[Fuzzy Dunlop]

Yeah acctually the vast majority of US commercial launches have used solid upper stages. You can easily plan the trajectory by adding balast to the payload to make it up to a nominal weight. The RCS system of the payload is almost always enough to fine tune an orbit if nessecary.