Any value in having SRBs after stage one?

[The Ideal Gas Lawyer]

They're so heavy when not firing it seems to me like they're only good for the first stage to give your ship a kick in the pants and get some initial velocity. After that, is there any good reason to use them instead of liquid fuel engines? Especially if you can asparagus the tanks and constantly be dumping dry weight.

I've stayed away from using boom trashcans after the start every since some early disasters

[robly18]

They're probably gonna be a hecka lot more useful on career mode. The main reason NASA uses those is because they're cheaper to make than liquid fuel boosters. So you can expect these to cost like 100 of whatever the currency is while liquid boosters (fuel+engine) might cost up to 1K.

[RoboRay]

Right now, no, they are really only useful for getting off the pad up to terminal velocity quickly. And they're of questionable value for that.

When we're spending money on parts in career mode, though, SRBs are going to be very popular.

[Guest]

My attempts at using SRB's to supplement upper stages have had scattered success. As in successfully scattering the launch vehicles across Booster Bay.

[RoboRay]

"Booster Bay"

Oh, I'm definitely going to be using that name from now on.

[BeefTenderloin]

If I'm not mistaken, the Orbital Industries launch vehicle uses a second stage that utilizes solid fuel. I believe this is due to the original design being capable of reusing old "Minuteman" parts.

[spacecake]

Speaking of old, how old is that screenshot?

[SpaceCowboy]

The Delta III had nine SRBs: six that ignited on the ground and three that were air-lit and started after the first six were jettisoned.

[lobsterbark]

If making an icbm, then using srbs for stage 2 is actually quite useful.

[erkha343]

SRB's are cheap, you'll be using them more once career mode is implemented.

They have much higher twr too

[Westo454]

Right now, I don't use SRBs unless I absolutely must. I am definitely going to start seeing an increase in my SRB count once I get Career mode though.

[HGGundamReviews]

In my case I find them very useful. On most of my heavy lifters I add a layer of the large SRB's on radial decouplers, and then on top of them and set of the small SRB's on decouplers. The combination work very well together. The overall small amount of thrust the small SRB's give add just enough extra efficiency to the over all craft that the large one's will last generally at least 3 to 4km higher than without the smaller ones to kick the whole ship up just that extra little nudge.

[Noticeably FAT]

I've been considering adding small 'booster packs' to the bottom of my interplanetary drives if I know I'm going to need more than 1km/s for the transfer just to save on that precious liquid fuel. I suspect that they will be more trouble than they are worth, but I still wanna try.

[Elemental]

I like to use them for impact probes. It just feels way more cool to light the solid booster and send it careening at the object.

[Scoundrel]

SRBs are best used <13km altitude to keep your 2gs of acceleration through the thickest part of the atmosphere. Once you're at about 13km the atmosphere significantly starts to thin out and you should be starting your gravity turn if you haven't already. Once the gravity turn has been performed, small SRBs may help if you want to throttle back on your main engines to conserve fuel for orbital maneuvers. The problem with doing that though is that they will sort of hinder you as you need gimballing engines to finish your turn since aero control surfaces will be less than useful, and RCS is kind of wasted on anything except translation. And anyways, at high altitudes, you're better off staging liquid engines than hauling up srbs.

[leax256]

you could make some sort of solid booster "crane" to slow your decent in a landing, no not really any other use.

[SunJumper]

There's one use. Jeb's will states that he wants to be launched directly into the sun using only the RT-10s. That would make a grand challenge.

[Designer225]

Thus booster be important, thus rocket shall explode! --- Jeb

I don't use boosters often, but I usually use them to boost the rocket. Yeah, when we are playing in Career mode, this would be a whole lot of heck of usefulness and cheapness.

[Catullus]

Using SRBs in space isn't a good idea, they've got miserable Isp.

[Designer225]

Using SRBs in space isn't a good idea, they've got miserable Isp.

Yeah. Besides, you just can't cut off the motors once they're activated. I think in space we should use liquid engines in space, and use combined liquid engines and solid boosters for launch, to save money.

[Paul Kingtiger]

SRB's are always fueled up so for a military missile they are great, you can launch them straight away. For civilian use they have one big advantage and a lot of drawbacks.

First up, they don't cost very much with is good right? However:

1) They can't be controlled, which means once lit they burn until they run out of fuel. This limits what you can do with them and means they can't be turned off in a emergency or throttled.

2) The fuel and exhaust gas is really toxic, which has an environmental impact. The area around Kennedy Space Center is a nature reserve and is measurably damaged by every launch using SRB. Cars close to the launch site have their paint damaged!

[foamyesque]

There actually are good IRL reasons to have a solid non-first stage; many satellites are placed in their final orbits by a solid booster, for example. Solid rockets are, typically, much less complex than liquid ones, and they are also far more energy dense (in terms of MJ/m^3) than liquids because of their far denser fuel. This means they can be made much more compact.

[Temstar]

There actually are good IRL reasons to have a solid non-first stage; many satellites are placed in their final orbits by a solid booster, for example. Solid rockets are, typically, much less complex than liquid ones, and they are also far more energy dense (in terms of MJ/m^3) than liquids because of their far denser fuel. This means they can be made much more compact.

Awww you're talking about Payload Assist Module. The reason why solids are sometimes used for final stage is because:

1. As mentioned, they're compact for the amount of energy they carry so they can fit inside small spaces like payload fairings or shuttle cargo by

2. They're very reliable because they're simple and have few parts that can go wrong. You won't want to have a situation where shuttle has got the payload to LEO but then have the PAM fail to fire

3. They can be designed as "spinners" where no guidance is needed at all and the PAM + payload is only stabilised by gyroscopic forces like a rifle bullet. This makes them very easy to install as an additional stage onto things not originally designed for them. You can't spin liquid stages because the fuel will vortex and behave unpredictably.

[SwagBoiFresh]

I reject all your realities and substitute Scott Manley's.

[Scoundrel]

Hahahaha! Touché SwagBoiFresh. Touché.