The Stones, a family of "Loonies" (residents of the Moon), purchase and restore a used spaceship and go sightseeing around the Solar System. After their visit on Mars, instead of returning home as originally planned, they decide to travel to the asteroid belt, where the equivalent of a gold rush is in progress, prospecting for "core material" and radioactive ores. The asteroid miners move around the Belt using small rocket powered scooters, basically an open framework with a rocket engine and only the essential navigation equipment. The twin brothers, Castor and Pollux, build their own scooter out of spare parts and a used engine they buy from a local trader.
This photo is a composite of a photo of my model of the scooter and astronomical background and asteroid images.