Solid Rockets

[Bill Phil]

I think the solids in KSP could really use some expanding.

We have a few awesome ones, literally. But there are no 0.625 meter SRBs or upper stage SRMs at all. These would add to the game in quite a way.

What if you don't need those 1.25 meter boosters, but something less? Then a 0.625 meter booster is a good size, right?

What if you want a cheap rocket, and using liquid upper stages would be too expensive? Then a solid upper stage could help out a lot.

I'm thinking the 0.625 booster could be modeled after the GEM series of boosters. And the solid upper stage (SUS?) could be modeled after a Star motor.

Basically, solid motors need some love in KSP.

Not to mention that it's showing an image of solids being used only as boosters, when they were used many times as upper stages.

EDIT:

Or even bigger solids, maybe 2.5 meter diameter. This isn't unrealistic at all. Since the INT-05 was a saturn IB with a 260 inch SRB first stage (rivaling, well, the S-IB stage) was a seriously considered launch vehicle.

EDIT2:

Thrust Vectoring, too. It's an actual thing. But on the smaller boosters it would be a bit overpowered.

EDIT3:

The RT-5 Flea is a nice addition to the game, however, a smaller 0.625 meter design is preferred.

Edited April 28, 2015 by Bill Phil

[AbacusWizard]

To take this in another direction: I'd like some larger solid boosters as well. I have a habit of building huge interplanetary starships, and putting them into orbit almost always involves not eight booster rockets but eight clusters of nine booster rockets each. Eight huge booster rockets would be much nicer to the part count.

[Vallius]

The game could use some second stage SRMs. Believe it or not, they are much more common than people realize.

[Bill Phil]

To take this in another direction: I'd like some larger solid boosters as well. I have a habit of building huge interplanetary starships, and putting them into orbit almost always involves not eight booster rockets but eight clusters of nine booster rockets each. Eight huge booster rockets would be much nicer to the part count.

Like on the Saturn INT-05 first stage? A huge solid motor.... I could see that.

[Yukon0009]

I third this request. Small SRBs could be placed early in the tech tree (as they share a lot with big fireworks) so we wouldn't have to research our way up to Oscar B and LV1 just to haves some nice small stages.

[Wolf Baginski]

Somebody made a procedural SRB mod, and there are other SRBs in the big-tank mods such a Novapunch, KWrocketry, and Space-Y. The procedural SRB can be toggled between a low-altitude and high-altitude nozzle on assembly. So a small diameter SRB optimised for high-altitude is possible if anyone wants to try out the ideas.

[Renegrade]

I'm pretty sure I've seen this before, and quite recently, in a different thread, but I supported it then, so I'll support it again now

+1 for more SRB variants!

(the vast, vast, VAST super-ultra-majority of rockets are solid rockets, considering things like missiles (almost all kinds) or fireworks or model rockets are indeed rockets)

[Hcube]

agreed ! the SRBs are pretty much trashed in KSP. A recent post (cannot paste link cause im on mobile but search it, it must 2-3pages back) mentioned adding thrust curves to SRBs also. (just like IRL)

i dont ask for a SRB combustion simulator 2015, but simply some thrust vectoring (maybe only the bigger ones, not the yellow small one because it´d be OP) and thrust curves would be NICE.

i personnaly don't really care much about solid last stages because since you cant turn them off you would need to do a crazy amount of work to calculate the exact amount of fuel to put in it to get your encounter...

Instead i'd like some "strap-on" slanted (i mean assymetrical) SRBs that stick to the sides if the core so that there is no gap between the SRB and the core due to the decoupler... maybe an integrated decoupler ? Much like the delta5 boosters, ariane 5 or even the soyuz ones (even tho those a liquid i know) !

[basic.syntax]

Agree with OP. I've seen a few videos of Space Shuttle designs with 4 S1 SRB's on a quad adapter, and done the same many, many times. I think v.90 Mk3 parts lead to heavier stuff than the v.25 "NASA pack" SRB and its SLS-focused parts envisioned.

Helping Hcube - If other readers haven't seen it, check out the "Make SRB's better" thread.

[Bill Phil]

i personnaly don't really care much about solid last stages because since you cant turn them off you would need to do a crazy amount of work to calculate the exact amount of fuel to put in it to get your encounter...

Instead i'd like some "strap-on" slanted (i mean assymetrical) SRBs that stick to the sides if the core so that there is no gap between the SRB and the core due to the decoupler... maybe an integrated decoupler ? Much like the delta5 boosters, ariane 5 or even the soyuz ones (even tho those a liquid i know) !

Actually, if you know Tsiolkovsky's Rocket Equation well, you can create an equation to solve for the amount of payload with a given Delta-V.

For example, if you want to send something from a 70km above sea level LKO to escape velocity, you need ~1002.5 m/s of Dv. You would divide this Dv by the effective exhaust velocity(Ve), and then put e (~2.718) to that power. This gives you the mass ratio. Let's simplify that to R...

Now we can solve for the payload. Which is added to both the full mass and the empty mass of the stage.

Rocket Equation:

Dv = Ve * ln |(M+x)/(M1+x)|

Solving for "x" and substituting "e^Dv/Ve" for "R" gives you:

x=(RM-M1)/(1-R)

Where "x" is the payload mass (counting extra structure to support it, and other things...), "M" is the empty mass, "M1" is the full mass.

With:

R=1.531477557420375

M=250 kg

M1=750 kg

You get about 690 kg for your payload to escape velocity.

I do agree about the last paragraph and the boosters, though.

Edited April 11, 2015 by Bill Phil

[Starwhip]

I'd like to see this in the game myself... so I made a mod for it.

+1. Also, thrust curves.

[Bill Phil]

I'd like to see this in the game myself... so I made a mod for it.

+1. Also, thrust curves.

I support your mod, sir.

*Tips hat

Reminds me of segmented boosters. Also a realistic thing.

[Hcube]

Actually, if you know Tsiolkovsky's Rocket Equation well, you can create an equation to solve for the amount of payload with a given Delta-V.

For example, if you want to send something from a 70km above sea level LKO to escape velocity, you need ~1002.5 m/s of Dv. You would divide this Dv by the effective exhaust velocity(Ve), and then put e (~2.718) to that power. This gives you the mass ratio. Let's simplify that to R...

Now we can solve for the payload. Which is added to both the full mass and the empty mass of the stage.

Rocket Equation:

Dv = Ve * ln |(M+x)/(M1+x)|

Solving for "x" and substituting "e^Dv/Ve" for "R" gives you:

x=(RM-M1)/(1-R)

Where "x" is the payload mass (counting extra structure to support it, and other things...), "M" is the empty mass, "M1" is the full mass.

With:

R=1.531477557420375

M=250 kg

M1=750 kg

You get about 690 kg for your payload to escape velocity.

I do agree about the last paragraph and the boosters, though.

well, i am aware that it can be calculated, but when you design your rocket, you don't know how much deltaV your transfer will need yet. you only precisely know it once you are in orbit and your maneuver node is set up, because the deltaV needed can vary very much depending of planetary alignement, starting orbit etc ! (and we all know that a .1m/s can make the difference)

i think that you see what i mean now !

[Bill Phil]

well, i am aware that it can be calculated, but when you design your rocket, you don't know how much deltaV your transfer will need yet. you only precisely know it once you are in orbit and your maneuver node is set up, because the deltaV needed can vary very much depending of planetary alignement, starting orbit etc ! (and we all know that a .1m/s can make the difference)

i think that you see what i mean now !

No one said you couldn't use liquid rockets in conjunction with solids. Use the solids to escape Kerbin, and then rely on a much smaller probe to get your remaining Dv.

Plus, you just look up when to transfer. Pretty easy as well.

[Admac]

Good News Everyone!!

KW Rocketry and SpaceY have some sweet 2.5/3.75m SRBs up to 150+ tons.

USI Sounding Rockets has some very early game .35m and .685m SRBs along with tiny parts for them

Sounding Rockets;

http://forum.kerbalspaceprogram.com/threads/102502

KW Rocketry

http://forum.kerbalspaceprogram.com/threads/51037-0-25-KW-Rocketry-v2-6d2-Available-0-25-Compatibility%21-16-10-2014

SpaceY

http://forum.kerbalspaceprogram.com/threads/100408-0-90-WIP-SpaceY-Heavy-Lifter-Parts-Pack-v0-11-%282015-02-18%29

[Bill Phil]

While that's welcome, it would still be very good for stock.

[Wahgineer]

It has also been mentioned in the latest devnotes that they're adding a new SRB: the RT-5 "Flea". The name "Flea" suggests that this new SRB is probably 0.625 meters.

[SmallFatFetus]

2.5m solids are desperately needed. Also, the existing solid boosters have pretty crappy models/textures, and could use an update. In fact, I think squad needs to take a serious look at anything that has remained the same since .17 or so. (1.25m cockpits, aerospike, 2.5m fuel tank textures, mainsail texture, and so on)

SmallFatFetus

[Giggleplex777]

SRBs got more neglect in 1.0. That was very disappointing.

[passinglurker]

You know this is a big opportunity mod wise. There is a big enough gap between solids and liquids for hybrids to find a niche!