There are many types of engines. They come in all shapes and sizes; powers and plusses; boons and banes. For most people, one Cosmic Explorer can last a lifetime. However, intrepid adventurers like you are no such people. You may be constantly buying/selling installing stuff. There are three “types” of engines, determined by their fuel sources. The first is Nuclear. These use fusion/fission to power/propel stuff. Nuclear Engines are powerful but require a steady stream of Uranium. Luckily, Uranium is fairly cheap and Nuclear engines require little other maintenance but Uranium. The second is Gravitational. Gravitational engines manipulate the gravity of large celestial objects for power. These require no fuel, but a lot of precision, and often break and become useless until repaired. What’s more, they tend to be very expensive. The third is Biological. Biological engines harness the powers of a living creature/organic substance, like a psychically gifted arthropod or an energy producing tumor. Unfortunately, this requires not only the capture and enslavement of these creatures, but the obtaining of another life support system To actually install/upgrade an engine, you need either training in Science or a mechanic (found in most towns). It takes 6 hours to do so and requires only Vehicle Tools and the Engine you wish to install. To upgrade an engine, you need only Vehicle Tools and the components needed to upgrade the engine.