 Why were there no guards present in the ship?
The Spacemen's was a sanctuary, a rest club where in-coming pilots and crewmen could relax before leaving for another voyage. The rule that no females could pass its portals was strictly enforced. A theater to the grizzled colonials on this side of the planet meant a shack on stilts over the muck, zilcon wood seats and dingy atobide lamps. On the stage four Earthmen, two Martians, two Venusians, and one Mercurian sat on an upraised dais. Before each set stood an Earthman operator. I will only say that on this stage are nine visi sets, each tuned to one of the nine planets. For every question missed, the sender will receive a check for one thousand planetoles . Questions from Mars, from Earth, from Saturn flowed in the visi sets.
 The ship was self-operating to defend
 They had all been eliminated by the Green Flames  the metal envelope was the only guard  The ship was well hidden to not need guards  The ship was self-operating to defend