Orbital Mass Driver

Orbital mass drivers (OMD) are electromagnetically driven surface to space launch systems. They are divided into two types - passenger and cargo. OMDs are typically seen on worlds with little to no atmosphere.

OMDs are a series of rails and accelerators which accelerate a payload fast enough to enter, or even exit, orbit. Typically, low orbit drivers accelerate a payload into a parabolic trajectory and the payload itself circularizes the orbit. Interplanetary drivers may use tugs at the destination to catch and decelerate payloads.

While not as simple as traditional rocketry, OMDs are a fairly cheap and consistent method to launch cargo into orbit, requiring little to no metamaterials. OMDs are typically a stepping stone to constructing space elevators for developing colonies.

Cargo drivers are OMDs built specifically to deliver non-living materials into orbit. Since there are fewer G restrictions, cargo drivers are typically high speed linear accelerators. Payloads can experience anywhere between 10-100gs of acceleration depending on the design of the driver.

Passenger drivers are large and complex launch systems meant to deliver living beings into orbit without killing them. This is typically achieved through extremely long linear drivers or huge circuits that accelerate the payload at a constant 3-5gs until up to speed. Passenger drivers have extra safety requirements which include emergency braking zones, escape vehicles, and multiple redundant systems.

OMDs become less efficient relative to the atmosphere's thickness. Thicker atmospheres introduce issues such as heating through drag, the need to build the exit higher, and compensation for poor weather.

In little to no atmosphere, OMDs cannot rely on the atmosphere for cooling, and as such, requires large active cooling systems or long downtime to dissipate heat on the rails and in the system.