> 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 doctr

> 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.