This template is used exclusively for flown rocket engines used on orbital launch vehicle. The decision is on the intent of the vehicle, a suborbital mission of an orbital launch vehicle sill counts. Sub-orbital launch vehicles per se are excluded, anything atmospheric in not part of this. Pure orbital spacecrafts, i.e. the payload of a launch vehicle, does not counts.
- Orbital launch vehicle main propulsion that was also used for suborbital vehicles. Example: Algol.
- Orbital launch vehicle upper stages even if they are pure space vehicles, but are never launched as payloads. Example: AVUM's RD-843.
- Rockets engine of orbital upper stages, even if they are also used on spacecraft. Example: S5.92, used on Fregat, but also on Phobos 1 and Phobos 2 Mars spacecrafts.
- Main propulsion of stages that were also used as spacecraft: Example: Agena's XLR81.
- Military engines when used for non-military or non weaponized applications. Example: SR-118 used on both Minuteman III ICBM and the [Minotaur III]] launch vehicle or the RD-869 used on the upper stage of Dnepr-1 and the R-36MUTTH MIRV.
- Spacecraft propulsion engines and motors. Example: R-4D.
- Thrusters if they are used as the main propulsion of the spacecraft. Example: Dragon's Draco.
- Military payloads like MARV, MIRV and other warheads breaking engines never used on non weaponized versions. Example: most ICBM.
- Thrusters when used exclusively for station keeping, attitude control, reaction control system and/or as ullage motor.