A Rube Goldberg solution would be something like, the commander pulls a string, dropping a piece of cheese. A rat, sensing the cheese, runs over, pulling a string. The string rings a small bell, where a trained parrot that has been conditioned to lay an egg at the sound of a bell, depostis one on a balanced cup. The weight of the egg causes the cup to drop, hitting a lever that releases a ball that rolls down a spiral ramp until it hits a scissors, which cuts a cord, releasing a weight that pulls the trigger of a gun, shooting a charge of explosive and separating the capsule from the booster. Easy peasy!
Reality was far more mundane, but equally as interesting!
For those of us in the “future rocket scientist” group. Estes had a flying model version, which is still in production as of a few years ago.