The Combustion Drive is a technology that allows the construction of Small Cargo and Large Cargo ships, Light Fighters, Recyclers, and Espionage Probes. In addition, all ships that use the Combustion Drive will have their Base Speed increased by 10% for every level of the Combustion Drive technology. After upgrading to level 5 of the Impulse Drive, the base speed of Small Cargo ships double and they henceforth proceed to use the Impulse Drive instead of the Combustion Drive when calculating speed and fuel efficiency.