Is it possible to orbit with only solid boosters?

[guitarxe]

So that means going to orbit while burning hot all the time right to the end, is it possible to achieve something like that?

[blorgon]

Why don't you try it out and report back? Best way to learn!

[Superfluous J]

Sure it's possible. It'd be a huge pain though.

"All you'd need to do" is make sure you have more than about 3500 m/s of dV, and then make sure you're in space and burning sideways long enough to pull your Pe out of the atmosphere. If you run out too soon, find a way to add some dV and try again. If you end up still burning once in orbit, then find a way to remove some.

But that sounds like too much work for me. As @blorgon said, tough, try it yourself

[MaxL_1023]

It is difficult, but possible. Your best bet is packing about 4 km/s of delta-v, trying to burn to a 200-300km apoapsis then stage something with ~1000 m/s to pull your PE up.

[James Kerman]

It is possible to go anywhere on SRB's as Stratzenblitz75 demonstrates:

 

Edited April 28, 2016 by James Kerman
Credit youtuber

[Streetwind]

In .90 when I played with RemoteTech, I had a smallsat launcher comprised of three solid stages for lifting commsats into Kerbin orbit. It's definitely possible and even cost-efficient, especially if you don't have to hit a specific altitude. Because of the way your ascent profile - and thus your individual piloting - affects dV cost to orbit, creating a SRB launcher that puts you precisely into a 75x75 km orbit is impractical - the slightest piloting mistake will make you miss orbit insertion. No, you build one that deposits you into a 75x125 orbit or so, and thus even with a crass piloting mistake during ascent, you can still limp into a lower orbit. And ideally your payload is something that wants to go higher than 125 anyway.

The one thing stock KSP lacks for the purposes of all solid launchers is the lack of a suitable solid upper stage. You'd want something small with a limited TWR and better-than-normal vacuum Isp (even SRBs can use vacuum nozzles, you know). But the only appropriately sized SRB stock KSP has - the Flea - has absurd amounts of thrust and the worst Isp of all SRBs. So for my career run there, I had a mod installed that added a suitable solid upper stage.

Edited April 28, 2016 by Streetwind

[Corw]

On a single SRB, it would be huge pain, because you would have to start with small TWR at launch which would get larger as you burn. You would have maximum thrust at point where you want to circularize, where you would actually want to fine tune your orbit with low TWR throttable system. So I guess it would be possible but major pain to fly.

[swjr-swis]

8 hours ago, guitarxe said:

Is it possible to orbit with only solid boosters?

Sure, on a single SRB even, if you accept just the Kerbal making it to orbit:

Theoretically, there's about barely enough dV in a single Kickback to make it to 75-80km orbit with a perfect gravity turn, but in practice, avoiding exploding parts and the lack of throttle control other than the initial limiter results in a very subobtimal trajectory. I tried a couple of times and fell about 200-300m/s short, so the only way to achieve orbit was to EVA and circularize just the Kerbal.

Which of course means that it could still be done 'just with solid boosters' if I added a small SRB up top (or even sepratrons, on just the decoupled command chair) for the final circularization stage.

[wumpus]

If you allow a coasting phase and fire up another SRB, it is easy.  If you have a sufficiently light load and a kicker, it is still easy (expect an extremely elliptic orbit).  I've come pretty close to Eve with only SRBs (including a lot of seperatrons), but didn't have the patience to figure out the exact time & date I would need to launch my rocket to really get an encounter (I'm guessing I was only a few hours off, but it took most of my seperatrons just to get to Eve's orbit).

[Temeter]

19 hours ago, 5thHorseman said:

@blorgonSure it's possible. It'd be a huge pain though.

Eh, its not that bad once you get used to it. The rockets in RSS/RO act kinda like KSPs SRB, although the much longer circularization burn allows for much more precision while doing longer burns.

Edited April 28, 2016 by Temeter

[storm_soldier2377]

I can imagine this being done with a Kickback SRB, reaction wheels, and a Mk1 command pod by doing a gravity turn as usual and pointing somewhere between the progrande and radial markers.

[guitarxe]

I finally managed to do it, but it was imperative that there was a burn-free coast to AP before circularizing. I could find no way to do it with a continuous burn, and I realized why. The problem being that by continuously burning, the craft is always at the PE, but you are trying to raise your PE. So the question is, how do you raise your PE when you are at the PE?

I tried doing radial burns, thinking that would shift altitude from the AP to the PE, since I had plenty of altitude to spare there, but that didn't work out.

Hm, now after thinking more about it, I think maybe the problem was also that I was doing a gravity turn the same way I would have with thrustable engines, so I was burning still too low in the atmosphere, so by the time the fuel ran out my PE was still under the atmosphere. I guess if I launch more vertically and pitch horizontally only once I have attained an altitude that I want to be my PE, then continuous burn to orbit could still work out...

[mrclucks]

Yes it is.  I believe I have watched a mission to Laythe(or eloo or Duna or something) and back using only SRBs(and sepertrons).  I can't seem to remember if they only use parachutes for kerbin re-entry or also for the other body.  I can't even fathom how long it took that person to finesse everything to make it possible.