Without materials such as metals, food, and fuel, a galactic empire would not last very long. All planets need food to survive, most need trillum for fuel, and some need metals to build ships. Keeping each planet supplied with the materials that it needs is as important a task as any other that an imperial ruler may face. There are five main categories of materials: supplies, trillum, metals, chemicals, and ambrosia.
The most important materials of an empire are probably food, medicine, and other basic necessities of life, commonly grouped under the label supplies. Most worlds are self-sufficient and do not need supplies to be shipped in, but some worlds are dedicated to a single industry and must import part of their supplies from other worlds. The amount of supplies that each world needs is directly proportional to its population. Millions will suffer and die if a world does not have enough supplies to support its population. Not only will this reduce the productivity of the world, but it will also increase the chance that the people will revolt against the empire.
Trillum is probably the next most important material. A combination of hydrogen and rare crystals, trillum is used as a high-yield fuel for ships and heavy industry. Without trillum, worlds cannot build ships or deploy fleets. Not all worlds are suitable for the mining and processing of trillum. Barren worlds are often ideal because they have large supplies of the components of trillum, but ocean worlds, for example, are very poor at producing the fuel.
Used for the construction of ships and industry, metals encompass all types of heavy materials including plasteel, chromium and titanium alloys, as well as graphite and synthetic compounds.
Chemicals include common substances such as petroleum, lubricants, acids, and catalysts, as well as the more exotic organic chemicals used in ambrosia production. Chemicals are needed for almost all kinds of industrial production.
The rare and powerful substance known as ambrosia is a sweet powdered drug often used in place of sugar. In addition to producing a mild euphoria, ambrosia also reduces the individual's need to sleep to such an extent that his or her productivity is increased substantially. A work force addicted to ambrosia is able to work so much more that the total output of the factory is increased by nearly 50%. Whole worlds addicted to ambrosia are not unknown, but great care must be used because of the horrible effects of the drug's withdrawal. Whenever an addicted world is unable to obtain enough of the drug, the madness and psychosis induced in the victims is so violent that massive world-wide riots are common. Fortunately, most worlds cannot produce ambrosia locally. Only certain worlds with the ideal biosphere can serve as ambrosia producers.