Beyond the Time Barrier

Major Bill Allison flies the X-80 experimental aircraft to sub-orbital spaceflight successfully, though losing radio contact in flight. When he returns to the airbase it appears abandoned, old and deserted. When Allison wakes, he finds himself in a dystopian underground city known as the Citadel. The rest of the inhabitants, including the Supreme's granddaughter Trirene, are deaf-mutes, and everyone except possibly Trirene is sterile.