Or you know, you could just not use solid rocket boosters at all. Solid rocket booster make absolutely no sense at all, they are only used because they represent a political interest.
Note how there was no attempt at using them for Apollo and no new rocket company uses them.
The only reason so many countries relay on them because it sharing costs with ICBMs.
NASA own internal investigation suggested the same thing, but politics is more important.
If there's significant overlap with ICBMs I could see it being reasonable from the perspective of maintaining military production readiness.
Imagine you need a bunch of people trained to do X, and machines capable of Y, in order to build your missiles, but you don't need many missiles right now, but if a war against a major power broke out you'd need to ramp up production massively and instantly. Either you keep making missiles you don't need, or you somehow train people and maintain machines without actually using them, either way you're spending just to maintain readiness for no immediate value. Or you find a close enough use where you can get some value by producing something similar enough that you can convert to military use rapidly.
That wouldn't be so much political pork as actually practical. But I know little to nothing in this area, so just speculation.
> If there's significant overlap with ICBMs I could see it being reasonable from the perspective of maintaining military production readiness.
In the US this is partly historical. The Shuttle style large solids have no practical military application.
In general, I think by now the technology has diverged quite a bit as the requirements for launching potentially humans and ICBMs is quite different. I don't know how closely the technologies are still linked between the solids used on rockets like Vulcan and ICBMs.
In France this is certainty the case for example.
> major power broke out you'd need to ramp up production massively and instantly.
Lets hope we don't need to rapidly ramp up production of ICBMs since they are mostly just used to carry nukes.
If you think its politically necessary to fund that infrastructure just do so with your military budget. Tying down other space activities, specially civilian, is a bad idea.
> In the US this is partly historical. The Shuttle style large solids have no practical military application.
The huge Space Shuttle SRBs were never an ICBM part themselves. The military angle enters the picture when you realize the SRB fuel is the same fuel used in ICBMs, made by the same company (originally Thiokol, then ATK, which merged with Orbital Sciences to form Orbital ATK, which was then purchased by Northrop Grumman.)
I would think that if you find yourself engaged with a major power, expending your supply of ICBMs, replacing them is probably one of the few things you no longer need to worry about.
Japan's space program focuses on cost effective solid rocket boosters and does not build ballistic missiles out of them. Liquid engines generally have the advantage in ISP, which is why they dominate large rockets. But solid rockets have substantial savings in manufacturing and operational simplicity that shouldn't be simply handwaved away.
> savings in manufacturing and operational simplicity
Solids are very dangerous and complex to handle. The end to end infrastructure cost absolutely does not make them viable.
Are you seriously suggesting something about operational simplicity when you are dealing with a material that is highly explosive and can easy kill a whole launch crew if badly handled?
In addition, solids require very expensive launch infrastructure to modify the boosters to fly specific routes. Check out the highly complex infrastrucutre the Europeans deploy in Kourou.
There is a reason, non of the new commercial companies even remotely want to touch solids, they are avoid like the plague.
The solid based Pegasus rocket is vastly more expensive then the air-launched liquid fueled Virgin Orbit rocket.
Japan with their solids never were a series competitor in the international launch market and their launch rates were always very low.
And solids are also never practically reusable as the expensive part is the whole fuel manufacture and infrastructure.
Solids are just a bad idea and make no sense when fully consider. Only nation state driven launchers would use them.
Nobody builds SRBs "out of" missile boosters, but they are built by the same manufacturers. Fat contracts for one keep the business afloat for the other, keep the workers for one busy and practiced for the other. It's welfare for defense contractors using the same technology, facilities and expertise as the weapons, NOT part re-use. Part re-use was never the argument, not with the Shuttle and not now.
> Japan doesn't have ballistic missiles.
The Japanese SRBs are built by Mitsubishi Heavy Industries. Do you know what else they manufacture? Missiles of course. Not ICBMs, but they do manufacture missiles, particularly the powerful SM-3 Block II.
Japan focused on solid fuels because they needed to build rockets that were impractical enough to not be usable as ICBMs.
They had to do crazy things like launch them sideways.
This comment makes no sense. Missile and rockets both go sideways. Modern missiles all use solid fuel. Japan's solid fuel rockets are build by Mitsubishi Heavy Industries, which uses the same fuel and manufacturing expertise to also manufacture missiles.
Note how there was no attempt at using them for Apollo and no new rocket company uses them.
The only reason so many countries relay on them because it sharing costs with ICBMs.
NASA own internal investigation suggested the same thing, but politics is more important.