In THE COSMIC ASTONAUTS, Tom Swift has tired of his "solarton" and "super-repelatron" propulsion systems: "The real hope...lies in finding a different type of space propulsion...If only I could come up with a brand-new approach!" The new type of propulsion is the harnessing of cosmic rays using space kites to catch the "winds" of the rays in order to power a space vehicle. NASA has considered such schemes which use the existing "solar-wind" effect for propulsion.
The cover art depicts a type of space tugboat. The controls include a steering wheel and crane-like levers. Astronauts do not fly spaceships with steering wheels. A steering wheel provides two-dimensional control while a hand controller is a three degree of freedom (three dimensional) device. Space navigation is not limited to a two dimensional plane of reference since the effect of gravity is all but removed. Though this is the case, the inclusion of the lever system offers a third degree-of-freedom for control of the spacetug. Actually, a crane used to construct buildings and scoop dirt from the Earth is a three dimensional machine. It is a able to move its lifting scoop in three directions at right angles from one another.