I think I've identified the artwork that was pinched - er, I mean, homaged - for that Weetabix picture card of a "Dumb-Bell Spaceship" ['Deep Spaceship' see below, posted 31st August] - please find it above! It's from a book called "Worlds in Space" by Martin Caidin (SWORD connection, via the Six Million Dollar Man and the Lifting Body!) and the art is by Fred l Wolff. The idea, as you probably already know, is that the atomic engine is in the smaller sphere, away from the crew in the larger sphere - see Arthur C Clarke's "The Sands of Mars" for further info!
Card courtesy of the Philosophic Toad