Joe Kenmore and his crew, astronauts with the Space Exploration Project, have been assigned to deliver supplies and defensive weapons to the Platform, mankind’s first space station.

Orbiting 4,000 miles above the Earth, the Platform was constructed solely by the United States after the United Nations had rejected the proposal. As a result, the Platform is now targeted by enemy nations suspicious as to its true purpose. Expeditions to and from the Platform are under constant threat of attack by ground to space missiles—which is precisely what happens to Kenmore and crew.

After some quick thinking and imaginative solutions, they manage to thwart the bombardment and safely arrive at the Platform only to be met with scorn by the Platform’s lead scientist, Doctor Sanford. Shortly after Kenmore and his crew unload the supplies, Sanford, on the verge of a mental breakdown under the constant threat of death, attempts to kill everyone aboard the Platform. After a second ship arrives carrying Sanford’s replacement, U.S. Navy Commander Brown, Kenmore and crew depart in their ship while some of the Platform’s crew escort Sanford off in another.

As both vessels approach the Earth’s surface, Sanford’s ship is promptly destroyed by enemy fire while Kenmore and crew narrowly evade destruction. Once back at base, Kenmore is informed that Space Exploration Corporation has been contracted by the U.S. government to build a Moonship. If the vessel survives the journey, the moon will become United States territory. Will Kenmore and his crew be the first men to venture to Earth’s as-yet unexplored satellite?

In terms of plot, Space Tug is a step above the typical young adult SF adventures of the 1950s. Although most of the conflict is external to the protagonist, Murray Leinster delivers surprising moments of depth in Joe Kenmore and his crew—Haney (whose first name is never revealed), native American Chief Bender, and the “midget” Mike Scandia—all of whom are depicted as technically savvy and scientifically literate. In fact, due to his size, Scandia is the most skilled among them in zero-gravity maneuvering—a fact in which he vociferously revels.

There is little fluff in this story, aside from a slight romance brewing between Kenmore and Sally Holt, daughter of Major Holt, the base commander. The pacing is fast, the tension is constant, and there is just enough technical jargon as to provide a sense of authenticity and verisimilitude.