Mining for SRBs

[Xyphos]

Random thought popped up, what if we could convert ore into SRB fuel? re-useable fleas? YES PLEASE.

[Grumman]

No thanks. Even if refurbished SRBs are possible, it's not the sort of thing we should be doing in the field.

[Godot]

I agree with Grumman.

Refurbishing SRBs is a little bit more complicated than (as for luqid fuel) just refilling some tanks.

You will have to examine the SRBs for damages before refilling them (after all, SRBs do a double duty of engine and tanks,

their hulls are therefore subjected to more thermal stress than those of any liquid fuel tanks)

and then press/bake the fuel into them in a very specific shape (with the outlet channel in the middle).

Not totally sure about it, but AFAIK it is even so, that the fuel for each segment of a SRB is refilled/rebaked separately, meaning, you would also have to diassemble the SRBs first, before refilling them.

Definitely no work that could be done in the field

[KerikBalm]

Sure, but the ISRU converter to make new solid fuel plugs is 100tons...

[ShadowZone]

Have to agree with the other guys: SRBs serve a certain purpose, which is not being reused throughout a mission

[Geschosskopf]

Not totally sure about it, but AFAIK it is even so, that the fuel for each segment of a SRB is refilled/rebaked separately, meaning, you would also have to diassemble the SRBs first, before refilling them.

I think you actually underestimate the difficulty. In KSP, SRBs are made the same way as rolling cigarettes. So the Kerbals have to lay out a huge sheet of paper, pour a line of propellant on it, then roll the whole long, heavy thing up evenly and glue the last edge .

However, I think you underestimate the difficulty of refurbishing liquid fuel engines. From what I understand, they pretty much had to rebuild the Shuttle's main engines after every flight so I'm waiting to see what Space X has to do, assuming they can ever actually recover a booster for reuse .

[softweir]

Indeedy! KSP engines are magically enduring, and their tank refilling technology is lightyears better than anything that exists in the real world.

The science in KSP is a lot better than most other games I can think of off the top of my head. KSP's science is definitely chewy, whereas most games are, at best, al dente. But it isn't hard science!

[Sharpy]

I believe it should be a job for off-world construction sites, not an ISRU you can load on a spaceplane. So, yes, if you've built a base with a VAB on Minmus, and you land your BAAAC there, you should be able to refuel. But a quick SRB restoration between Laythe and Tylo? Nope.

[Kaos]

This should go into suggestion not in general discussion. Nevertheless:

Refurbishing SRB is more complicated than just producing fuel (as already said by others), so this should be not simple doable. With a more complicated part than the ISRU unit this might be ok, but there is no reason for it, as SRB are worse in every aspect than fluid engines but for costs for initial launch. If one day mechanics is included to construct new parts on-site, SRB would be a good candidate for it, because constructing SRB is simpler than constructing other engines. But I do not see this feature to be included in the near future, albeit I would like it.

[Wjolcz]

No thanks. Even if refurbished SRBs are possible, it's not the sort of thing we should be doing in the field.

I agree. Can't really imagine how re-stuffing the SRB with solid fuel would work.

[TimePeriod]

You might as well drop the SRB's into pure nitric-acid instead of the ocean.

Ocean and anything which is not intended to go into it, does not mix at all.

[regex]

Considering that you get LiquidFuel, Oxidizer, and Monopropellant from "Ore", I don't have a problem with this. KSP glosses over so much detail in its ISRU that refilling an SRM or "Ablator" wouldn't be out of the ordinary.

[Red Iron Crown]

Realistic or not I'm not sure where I would even use this. Kerbin's basically the only place where SRBs make much sense, everywhere but Eve is easier to get to orbit and most don't suffer from poor atmospheric TWRs.

[Terwin]

Heavy, highly durant, low-isp rocket engines seem a lot less magical than being able to re-fill a solid rocket booster without needing to re-build it.

A 5 ton module that can re-pressurize the filler gas while refilling fuel tanks from an appropriate energy-rich ore also does not seem terribly magical, especially with a reasonable energy input into the process.

Considering their small system, it is not unreasonable to think that Kerbals took more of a Russian Durable aircraft approach instead of the US highly-tuned but delicate aircraft approach to space flight.

(I have heard that in the USSR it was reasonable to just bull-doze a crash off the run-way and deem the runway ready for use as opposed to the multiple-times-a-day manual policing of aircraft carrier flight decks double-checking for any stray bits or pieces that could get sucked into an engine and ruin the plane US approach)

[Fisk02]

I think its impossible without an big and heavy setup of machines to convert ore to solid fuel.

Thats the case in real life anyway.

[Sharpy]

You might as well drop the SRB's into pure nitric-acid instead of the ocean.

Ocean and anything which is not intended to go into it, does not mix at all.

AFAIR the SRBs used to launch the shuttles were landing in the ocean and recovered for refurbishing for the next launch.

[TimePeriod]

AFAIR the SRBs used to launch the shuttles were landing in the ocean and recovered for refurbishing for the next launch.

Yeah, I know.

Thou "refurbished" and "rebuilt" might be the same thing.

That also goes for any kind of rocket engine, they are not supposed to be in sea water.

[regex]

It's pretty magical. I mean, you're creating what essentially amounts to Aerozine50, nitrogen tetroxide, and hydrazine (from the thermal properties since KSP uses a nebulous volume "unit") from "Ore" and then running that Aerozine50 through your jet engines, nuclear engines, and rocket engines, all of which are infinitely throttleable, infinitely reusable, and infinitely ignitable. It is not at all a stretch to say that the ISRU unit should also make Ablator, SolidFuel, and even Xenon from this magical "Ore".

[Red Iron Crown]

It's pretty magical. I mean, you're creating what essentially amounts to Aerozine50, nitrogen tetroxide, and hydrazine (from the thermal properties since KSP uses a nebulous volume "unit") from "Ore" and then running that Aerozine50 through your jet engines, nuclear engines, and rocket engines, all of which are infinitely throttleable, infinitely reusable, and infinitely ignitable. It is not at all a stretch to say that the ISRU unit should also make Ablator, SolidFuel, and even Xenon from this magical "Ore".

Someone should make a mod for more realistic ISRU.

[regex]

Someone should make a mod for more realistic ISRU.

I really need to get back on that.

Anyway, it's not entirely the ISRU representation that is at issue here. Everything else suffering from KSP-itis adds up until you get to a point where arguing over how realistic it is to repack an SRM is just kind of silly because the entire system is silly.

[Sharpy]

Someone should make a mod for more realistic ISRU.

first thing to change, conversion ratio. It's ridiculous that the large ore tank is the best wet:dry ratio tank for LF only engines. You're better off mass-wise packing 33 large ore tanks + ISRU than one LF Fuselage Long.

1 ton of ore should convert to maybe 100kg of fuel, not 1 ton of it.

[regex]

first thing to change, conversion ratio. It's ridiculous that the large ore tank is the best wet:dry ratio tank for LF only engines. You're better off mass-wise packing 33 large ore tanks + ISRU than one LF Fuselage Long.

1 ton of ore should convert to maybe 100kg of fuel, not 1 ton of it.

First thing to change is to throw out the concept of "LiquidFuel".

[Red Iron Crown]

first thing to change, conversion ratio. It's ridiculous that the large ore tank is the best wet:dry ratio tank for LF only engines. You're better off mass-wise packing 33 large ore tanks + ISRU than one LF Fuselage Long.

1 ton of ore should convert to maybe 100kg of fuel, not 1 ton of it.

The Mk1 LF fuselage would like a quick word with you.

[Sharpy]

Yeah, I know.

Thou "refurbished" and "rebuilt" might be the same thing.

That also goes for any kind of rocket engine, they are not supposed to be in sea water.

I really don't think so. They survive several megapascals of pressure inside, stress of lifting several hundreds (thousands?) tons at a few g of acceleration, temperatures of a good few thousand kelvin, contact with what is essentially a sustained explosion and lots of concentrated oxygen being released at high pressure and overheated, and then a phase of suborbital flight through nearly vacuum, followed by heat and stress of reentry. And crash into the ocean, only somewhat slowed down by the parachutes.

And then plain saltwater of all things would destroy them?

I guess you are right though: dropping them into pure nitric acid would have the same effect. That is none at all.

[TimePeriod]

I guess you are right though: dropping them into pure nitric acid would have the same effect. That is none at all.

How fast are these things hitting the water again? 5m/s ? 10 m/s? 30? 50? I don't know.

What I do know is anything going above 30m/s (60miles/h- 100km/h) will yield some serious kinetic energy upon contact with water. It might as well land on concrete.

Also, why the hell would SpaceX want to land their rockets onto a platform if not to reduce the cost of refurbishing the engine or parts of the craft?