Upper Stage Solid Fuel Engines

[More Boosters]

Hey, I know that SFRs are mostly used for take off with few examples of vacuum use, but I had an idea for a pretty gamey but still sensible (from a gameplay perspective) SRB for KSP that basically has high vacuum ISP, modest thrust, immodest cost, and perhaps an alternative mode that allows it to burn half as fast. I'm thinking about a solid fueled engine that is meant to be used for injection burns, so is there any feasibility in such an engine? If there is, what would it look like? If it's not feasible, how close can you get to a proper vacuum SRB with a good ISP?

[Dkmdlb]

Perhaps something like ATK's Star upper stage motors? Solid motors with Isp approaching 300 seconds in variety of sizes meant for vacuum operation. Would be nice to have something like that in KSP.

https://en.wikipedia.org/wiki/Star_48

[Streetwind]

I'm fairly sure there's a mod that has all the Star solid motors. I just can't remember the name right now Anyone?

There's also RLA Stockalike, which has one that very neatly fits with the stock parts. But it's still winding up for a 1.0 release 8so close though).

[Aethon]

The New Horizons mission to Pluto used a Star 48 kicker as it's last stage. It's very reliable.

The Orbital ATK rocket catalog.

http://www.orbitalatk.com/flight-systems/propulsion-systems/GEM-strapon-booster-system/docs/orbital_atk_motor_catalog_(2012).pdf#search="Star 48 srb"

[Slam_Jones]

As near as I'd work out, you'd need a different one (or a different configuration) for each different destination you may want to go to. Since you can't exactly un-light an SRB (or maybe you can in space? I can't imagine how though), even a little too much or too little could become a big problem.

[Kryten]

Solid final stages are also very common for organisations that are just starting their space programs, and have difficulty producing efficient small liquid stages. The CZ-1 that launched China's first sat, Juno and Vanguard in the US, Paektusan and Unha-2 in the DPRK, the british Black Arrow, et.c.

As near as I'd work out, you'd need a different one (or a different configuration) for each different destination you may want to go to. Since you can't exactly un-light an SRB (or maybe you can in space? I can't imagine how though), even a little too much or too little could become a big problem.

Motors of this type are either designed so that small amounts of propellant can be drilled out to adjust the impulse, or with blow-out panels to stop thrust.

[Aethon]

IIRC, the Star 48 kicked NH a little to hard toward Jupiter and they had to use on board propellant to slow down, so the Star 48 got to Jupiter before New Horizons.

[Slam_Jones]

-snip-

Motors of this type are either designed so that small amounts of propellant can be drilled out to adjust the impulse, or with blow-out panels to stop thrust.

Aha, clever.