> you can't keep a liquid-fuelled rocket permanently fueled so the Minuteman was developed as a solid rocket fuel booster.
You absolutely can! The Soviet doctrine was to use storable liquid propellants in their ICBMs - typically unsymmetrical dimethylhydrazine (UDMH) as the fuel and nitrogen tetroxide as the oxidiser. I don’t know if they need the fuel/oxidiser replaced periodically but that combination is storable for over a decade.
The US went with solid rockets as they are more reliable - no turbines or valves etc - at the expense of performance, but the US perfected making large solid rockets before the USSR. The USSR however perfected oxidiser-rich staged combustion which extracted a lot more performance.
Storable liquid propellants are still used on satellites and deep space missions that need to perform large course corrections during their missions.
You absolutely can! The Soviet doctrine was to use storable liquid propellants in their ICBMs - typically unsymmetrical dimethylhydrazine (UDMH) as the fuel and nitrogen tetroxide as the oxidiser. I don’t know if they need the fuel/oxidiser replaced periodically but that combination is storable for over a decade.
The US went with solid rockets as they are more reliable - no turbines or valves etc - at the expense of performance, but the US perfected making large solid rockets before the USSR. The USSR however perfected oxidiser-rich staged combustion which extracted a lot more performance.
Storable liquid propellants are still used on satellites and deep space missions that need to perform large course corrections during their missions.