Poderia ser Absolutamente Inflexível por Robert Silverberg. Aqui está um resumo (retirado de aqui ):
In the Robert Silverberg story Absolutely Inflexible, the main character, Bureau Chief Mahler, lives in a future where time travel is possible but only to the future. It is also a society where all diseases have been eradicated and no one has been immunized in decades. Thus it is not safe for these people to be released into the general population and they are quarantined on the moon. All of the time travelers are brought to Mahler and his "absolutely inflexible" attitude towards them means they are always quarantined. However, one day a man is brought to him in the regular decontamination suit and says he has a two-way time machine which will bring a person to the future and back. The man seems to recognize Mahler and realizes that he is doomed to be sent to the moon. Mahler decides to test the new machine and goes to the past and back to his present. When he arrives, he is immediately put into a decontamination suit and is brought to the bureau office where he talks to Mahler from his past. It is revealed that the time machine is stuck in a causal loop.