IIRC the main thing Soviets feared was surprise strike on Moscow by nukes launched from a space shuttle. This sounds rather absurd given that preparing a space

IIRC the main thing Soviets feared was surprise strike on Moscow by nukes launched from a space shuttle. This sounds rather absurd given that preparing a space shuttle for launch takes literally months. But the idea was, as far as I can tell, that it would launch on a regular mission, then use its heat shield and aerodynamic surfaces to change orbit inclination radically while out of reach of soviet radar, resulting in totally unexpected direct overflight of Moscow, making a decapitating strike possible.