Medium-future space colony/alien-contact yam featuring some ingenious scientific speculations. When a gas-giant planet, Iris, wanders into the solar system, the youthful crew of the ship Deepstar--intending to colonize Neptune's moon Triton (the solar system is crowded these days)--decide instead to tackle Iris' moon Ocypete. Deepstar's virtually indistinguishable crew, led--sort of--by disturbed tough-guy Brendan Sealock and confused musician John Cornwell, are preoccupied with full-brain computer links (nobody really understands anybody else, you see), computer-generated private realities, and incessant real-time sexual encounters. At first, all goes well on Ocypete; the colony takes shape. But then, buried beneath the ice of Iris' other moon, Aello, the colonists discover a huge alien transport ship, still partly functional Thanks to all that computer expertise, the crew are able to talk to the alien vessel, learning that a second, planet-sized, spaceship is buried in the middle of his itself! Unfortunately its alien computer-brain interprets the crew's probes as an invasion, and retaliates. Seems that, billions of years ago, some lonely aliens decided that their purpose in existence was to roam the universe, creating new lifeforms--until the aliens themselves died out and left their machines to carry on the work. The scientific details and exposition are the chief attractions here. Most of the remainder translates as wearisomely trite computer-age adolescent agonizing Overblown, then, and only patchily alluring.