Rip Foster Rides the Gray Planet
 Freshly graduated and commissioned Planeteer (the space-going equivalent of a Marine) Lt. Richard Ingalls Peter ("Rip") Foster, already contending with inter-service rivalry with the Space Force (equivalent to Navy) crewmen with whom he serves, is tasked with retrieving an asteroid made of pure thorium from the asteroid belt and bringing it to Earth for use as fissionable material. In this he is opposed by agents of the "Consolidation of Planetary Governments", who also seek control and use of the asteroid.