Off the Beam and two more stories

Excerpt: "Thirty hours out of Mars for Terra, the Solar Queen sped along her silent, invisible course. No longer was she completely severed from all connection with the planets of the inner system; the trick cams that controlled the beams at Venus Equilateral kept the ship centered by sheer mathematics. It was a poor communications system, however, since it was but a one-way job. Any message-answe...