Interstellar travel involves two main types of engines. Each can enable travel over great distances, but both are very different and require different ships and technology to work.
Jump drives make possible two different methods of travel. They can reach light speeds, or they can jump.
Traveling at light speed is efficient and safe for in-system trips, but not practical for traveling between systems, as it would take years to reach the destination. For that, a jump is required. This is the jump drive's unique ability.
When powering for a jump, the jump drive creates and expands an EM field. Anything caught in this field will make the jump. The bigger the ship, the longer the jump preperation will take—the EM field has to expand to encompass the entire ship for the jump to be successful and not leave part of the ship behind. The time it takes to expand the field also increases exponentially the larger it gets, so most ships with jump drives are very small. Speed is essential in making a jump where interference from the environment or from enemies might occur. The jump sequence is easy to disrupt.
Once the jump sequence is complete, the jump itself occurs. Jump distance varies depending on the quality of the engine, but even the most rudimentary models can make a jump several systems away. The jump occurs instantly, and since jumps drives are capable of such extreme distance, they're favored by surveyors and explorers. After a jump, the drive must re-calibrate itself before another jump is possible, a process which takes an hour with the most advanced models, and up to two hours on average.
Ships with jump drives are called starjumpers.
Ships likely to use jump drives
- Explorers and surveyors favor jump drives for their distance capabilities, and because these jobs are possible with small ships and limited crews.
- Stealth and Surveillance
- A small enough vessel can make a jump in seconds, provided the drive isn't in re-calibration, so spies and surveillance vessels often use jump drives.
- Charter passenger vessels
- These small, luxurious private passenger ships are supremely expensive, but they'll get their wealthy patrons to any destination they like in minutes.
- Single-pilot private ships
- If someone with the money and means wants a ship just for themselves, a starjumper is the way to go.
- On the biggest passenger ships, the lifeboats and emergency shuttles will often be equipped with rudimentary jump drives capable of making a single, pre-programmed jump to a sanctuary destination.
DM stands for dark matter. These engines are huge, and thus require larger ships to hold them. They're capable of FTL travel, with the exact speed depending on the specifications of the engine model. DM Engines are used for interstellar travel in ships too big to make a jump drive convenient. DM engines create no jump effect, but rather propel the ship through physical space at FTL speeds. They are hardy and their design and tech is straightforward, making them difficult to disrupt, though they take a considerable time to warm up and get going from a depowered state. Their dark matter radiation interferes with the finicky jump drives, so the two engines cannot be efficiently used in the same ship.
Ships likely to use DM engines
- Cruise ships
- Cruise ships tend to be large, and have no need to travel instantly, so they're equipped with DM engines.
- Commercial passenger vessels
- For transporting a large number of people between systems.
- Military ships
- With the exception of small stealth and surveillance ships, most military vessels will be large enough to warrant DM engines.
- Transport ships
- Large transport/cargo ships will almost always utilize a DM engine.