The Sorcerer's Apprentice / D. Bilenkin
A special emergency, analogue to the current Ministry of Emergency Situations, was that nervous knot on which all earth-space communication lines were closed; she had a powerful computing park, a huge informatics. How, without the help of a crane and the like, in a deep pit, carefully lower a steel cube weighing three tons? How to find ways of storing a substance that dissolves everything? The answers to such questions are known to the employees of the Special Emergency, the magicians of thought. Now, to save people, it was necessary to shift the orbit of the asteroid.