On the command deck, the trajectory plot updated. The ship’s vector line bent away from the red swarm. It was working.
Outside, the last battery tumbled end over end into the stars—a small, dead mass carrying away the momentum the Ulysses no longer needed. And the ship, lighter by forty tons and a thousand stories, limped toward home.
Mira placed six shaped charges at the rotor’s stress points. Her hands were steady. She pressed the detonator. action reaction and momentum conservation
The cargo ship Ulysses was dead in the black. Its fusion drive, a colossal cylinder of magnets and nozzles, had seized. Chief Engineer Mira Vasquez stared at the diagnostic hologram. The rotor, a fifty-ton beryllium-steel alloy wheel spinning at 15,000 RPM, had locked solid. Without its gyroscopic stability, the ship would drift. Without its reaction mass pump, they had no thrust.
But Captain Okonkwo wasn’t celebrating. “Mira, we’re not turning. We’re drifting sideways. The meteor swarm is wide. We’ll clip the edge.” On the command deck, the trajectory plot updated
She saw the problem. Their initial momentum was forward at 100 m/s. The side-jolt added lateral momentum. But the ship was now slowly rotating—the ejected mass had imparted a torque. In ten minutes, the bow would be pointing at the swarm. They’d fly sideways into the rocks.
“We need a second push,” she said. “Conservation of momentum requires that the total momentum of an isolated system remains constant. We’re the system. We have to throw something else.” Outside, the last battery tumbled end over end
“Reaction confirmed,” Mira coughed, smoke filling the bay. “We have lateral delta-v. Twenty meters per second and climbing.”