Spaceships produced and used by both the Empire of the Solar Throne and those outside the Empire are typically powered by both gravity-control tech and nuclear-fusion engines that allow easy interplanetary flight. Some larger spacecraft also are equipped with time-dilation drives that allow them to travel very nearly at the speed of light, with time passing in mere Earth days on the ship while years pass in the surrounding universe, permitting relatively easy interstellar flight. The larger ships with time-dilation capability are often equipped to carry smaller ships capable of only interplanetary space flight on their own. Spaceships also have artificial, onboard gravity to the gravity-control technology. Some ships (usually for military or law-enforcement purposes but also some civilian vessels both legal and illicit) are armed with weaponry, usually missiles powered by gravity-control tech, laser guns, and guns using electromagnetism or gravity-control tech to power solid, physical projectiles.