American spies discover the Chinese have built a weapon capable of destroying planet Earth, a "doomsday machine" if you will, and plan to use it within a matter of days. Immediately, Project Astra, a manned U.S. space mission to Venus, is taken over by the military and half of its all-male crew is replaced by women just hours before launch. The reason for this becomes apparent when, shortly after Astra leaves Earth's orbit, said planet is completely destroyed (in a cataclysm of stock footage)! Will the crew of the Astra make it safely to Venus? Will the human race survive?