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.
“Newton’s cradle,” she said with a tired smile. “You push one ball, the other moves. Except we were the ball that didn’t want to move. We just had to push harder.” action reaction and momentum conservation
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. The cargo ship Ulysses was dead in the black
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.” The rotor, a fifty-ton beryllium-steel alloy wheel spinning
Mira looked around the engine bay. Her eyes landed on the emergency fuel cells—twelve lead-acid batteries, each a half-ton brick. They were useless without the engine. But they had mass.
“On my count,” Mira said, positioning herself by the manual airlock lever. “We throw them out the forward port. Action: battery mass ejected backward at 10 m/s. Reaction: the ship gains forward momentum. But more importantly, if we throw them tangentially to our spin, we can cancel the rotation.”