The Gold at the Starbow's End: by Frederik Pohl
It was perhaps inevitable that it fell to an old-timer like Pohl to chart the decline of America following the assassinations of the 1960s and the supreme folly of Vietnam. No other sf story so effectively captures the death of hope at that time, or the subsequent exploitation of conspiracies to fragment and dispel opposition. The latter is a phenomenon which Noam Chomsky has commented upon repeatedly, viewing conspiracy theory as the most ineffective form of political dissent. But where does that leave Pohl, whose story quite perfectly poses a generational conflict which is suddenly thrown into context by a space mission made futile by conspiracy.
In an America wracked by riots and social unrest, the President and his scientific adviser, Dr Knefhausen, announce a mission to Planet Aleph in Alpha Centauri, crewed by the very bravest and best, the cream of the nation's youth. Besides the announced objectives of the mission, they hope the country will rally to the cause, as it did briefly for the moon landings, and that a shared sense of purpose and hope might renew the social contract, or at least consolidate the status quo. The young are duly dispatched into space, and the President collects his kudos. Mission accomplished. Except perhaps for the astronauts. At first they send back regular mission reports which contain personal messages as well as data relating to onboard experiments. They make a number of startling scientific breakthroughs, for which the President is delighted to accept credit. Later the messages become bitter as the astronauts realise the mission is a dupe - they will never reach Alpha Centauri and were never intended to; in disgust they turn to the I Ching and the Tarot and various exotic philosophies for comfort. They practice tantric sex. They start families. One of them dies and is somehow brought back to life. They invent a faster than light drive, but refuse to share the secret because it would be irresponsible. And it is now that the astronauts have turned into space-faring hippies that the President quickly passes blame for the mission onto Knefhausen, who laments the conspiracy of hippies above and hippies below. His execution is not enough to save the President, or even to save the country from civil war. And at any rate it does not matter - nothing matters, because the astronauts are now returning home, armed by their mission rather than for it, and their revenge threatens more than a smoking gun.
There are a lot of rather clever blanks in Starbow's End. Like many a conspiracy we are left to fill in these blanks from imagination; Pohl's only stipulation is that our imaginings must be the most cynical for the story to proceed. The rule of thumb is to assume the worst and then watch the astronauts evolve beyond opposable thumbs. And then assume another worst and watch them evolve beyond that, etc, until evolution is complete, which, ironically enough, may have been Knefhausen's purpose - he was, after all, an ex-Nazi. And this I think is the point - we suspect; we suspect everything, but we can prove nothing.
Pohl later expanded Starbow's End into the novel Lifeburst, a process sometimes known as a fixup.