Mysterious Big Dumb Objects have been found on Titan. It appears that they have been placed there by the “Others”, who will return to threaten mankind. Although somewhat disjointed and lacking focus, I nevertheless enjoyed this story of mankind under an unknown threat. The novel is vaguely connected with the Orion series.
kIND OF LIKE A FORE RUNNER OF HIS LATER NOVEL JUPITER.wITH THE GIANT ALIENS AND THE SURGICAL ENHACED ASTRONAUTS
I never really thought of that! Of course you are correct.