Mining for SRBs

[Edax]

I think Scott Manley mentioned something about New Horizon's (Solar System's fastest rocket) last detachable stage was a solid fuel booster, and it was burned while the rocket was already in space. So apparently solid rocket boosters have utility post-lift-off. But I think solid fuel was used for the mundane reason that they were very reliable.

[regex]

I think Scott Manley mentioned something about New Horizon's (Solar System's fastest rocket) last detachable stage was a solid fuel booster, and it was burned while the rocket was already in space. So apparently solid rocket boosters have utility post-lift-off. But I think solid fuel was used for the mundane reason that they were very reliable.

A Star 48 kick motor, probably used not only for reliability but also because New Horizons was already on top of a Centaur booster that would not achieve solar escape velocity.

The Minotaur V is a fully solid-fueled lifter that can take roughly half a ton to GTO, using a Star 48 followed by a Star 37 for the fourth and fifth stages. Both of those likely operate in near vacuum judging by how fast the Minotaur leaves the pad.

[Kaos]

New Horizons is using monoprop: https://en.wikipedia.org/wiki/New_Horizons#Propulsion_and_attitude_control

Then New Horizons was the fastest starting spacecraft ever, but not the fastest one. The Voyager missions could use multiple swing-bys to speed up that much that they are much faster than New Horizons right now.

[regex]

New Horizons is using monoprop: https://en.wikipedia.org/wiki/New_Horizons#Propulsion_and_attitude_control

It most certainly did not use monoprop to achieve solar escape velocity.

[Red Iron Crown]

New Horizons is using monoprop: https://en.wikipedia.org/wiki/New_Horizons#Propulsion_and_attitude_control

That's just for course corrections and attitude control, it used a Centaur LH2/LOX stage to achieve all of its initial velocity.

[regex]

That's just for course corrections and attitude control, it used a Centaur LH2/LOX stage to achieve all of its initial velocity.

Correction: It used a Centaur + Star 48 to achieve all of its initial velocity from parking orbit.

[Red Iron Crown]

Oops you're right, thanks for that.

[Kaos]

I know that. I must have misread one of the postings before, sorry.

[regex]

Oops you're right, thanks for that.

I just want the Star 48 to get its due in a conversation about SRMs.

[Sharpy]

I had no free fall in reality, yet, but in KSP my terminal velocity is about 200 m/s, which is rather 700 km/h than 200 km/h. But on parachute it is indeed mostly much slower.

"The terminal velocity of a falling human being with arms and legs outstretched is about 120 miles per hour (192 km per hour)" [source]

For a massive SRB that will be more, but since the drag rises with square of velocity, it won't be all that much more.

And the actual number for speed of a booster splashdown? 56mph, or 90km/h. Or 25m/s.

Source: around 7:20.

[BudgetHedgehog]

If I can make fuel, oxidiser and monopropellant from Ore, I see no problem with KSP allowing the production of Solid Fuel either. However, as pointed out earlier in the thread, the only places it's useful are Kerbin (where you can get it easily anyway) and Eve. Though, chances are, if you're going to be mining on Eve, you'll probably want to go for the higher Isp Liquid Fuel which you'll need anyway.. So yeah, 'why not? Doesn't seem worth it for me, but I've no problem with it being a thing'.

[Caelib]

Creating a solid propellant isn't feasible from anything except large production facilities.

[Xyphos]

"WHY?" you ask?

how about your Eve return lander lands on Eve with empty SRBs to begin with?

get a scientist to produce the SRB fuel, not from ISRU but from another part.

get an engineer to repack the empty SRBs

suddenly, this makes sense, as the lighter launch vessel would be better optimized and not a giant mundane behemoth.

(and it would make a great addition to go with the Size2 SRBs mentioned in my sig )

Edited August 5, 2015 by Xyphos

[BudgetHedgehog]

how about your Eve return lander lands on Eve with empty SRBs to begin with?

I would then question the benefit of hauling the dry mass of empty SRBs to Eve to fill them with a less efficient version of liquid fuel which I would need to convert anyway.

[Laie]

how about your Eve return lander lands on Eve with empty SRBs to begin with?

SRBs are inferior engines no matter how you roll it. Their only saving grace is the low price. Which is cool on the launchpad -- but once you start moving them off-world, that price appreciates handsomely. So basically, what OWK said.

Besides, SRBs will do you no good on Eve. They can't even lift their own weight there.

[Mad Rocket Scientist]

So, when you've lugged your SRB to eve, the moment you start to refine or into solid fuel, the booster ignites since you can't urn it off? No thanks.

[Skyentist]

What if you could literally mine for SRBs?

Like you go drilling and dig up a BACC or two.

I hear the Minmus flats contain large seams of Seperatrons.

[Sharpy]

I would then question the benefit of hauling the dry mass of empty SRBs to Eve to fill them with a less efficient version of liquid fuel which I would need to convert anyway.

Hauling it only Kerbin-Eve. Launching with them full, draining them on launch from Kerbin.

Personally, I wouldn't mind a mod that allows that, but I don't think that's a good idea for stock.

And Separatrons shouldn't be refuellable by ISRU, but KIS/KAS could carry "Separatron inserts", parts somewhat lighter than separatrons, which would "refuel" them - I'd imagine a separatron to be a metal tube on these small stubby legs with replaceable solid booster core inside, but requiring an engineer to remove the depleted core and mounting a fresh one.