Propulsion Manufacturers
| Company name | Engine | Engine type | Applications | Ref |
|---|---|---|---|---|
| Ad Astra Rocket Company | VASIMR | magnetoplasma | may be used for future Mars missions | |
| AE Aerospace | HIRE | hybrid ion rocket | ||
| AE Aerospace | Scearamjet | Electric Scramjet | ||
| American Rocket Company | hybrid rocket | The company became insolvent and was shut down in May 1996. Its lineage is part of SpaceShipOne. | ||
| ARCA | Executor (rocket engine) | Liquid Oxygen/RP-1 | IAR 111, Haas 2, Haas 2b, Super Haas | |
| The Elwing Company | Electrodeless Plasma Thruster | Electric Propulsion | may be used for future explorations missions | |
| Firestar Technologies | ||||
| Reaction Engines Ltd. | SABRE | precooled air-breathing rocket | planned to be used in Skylon | |
| Sierra Nevada Corporation | RocketMotorTwo | hybrid rocket | SpaceShipTwo | |
| SpaceDev | hybrid rocket | SpaceShipOne | ||
| SpaceX | Kestrel (rocket engine) | Liquid Oxygen/RP-1 | Falcon 1 second stage | |
| SpaceX | Merlin (rocket engine) | Liquid Oxygen/RP-1 | Falcon 1, Falcon 9, Falcon 9 Heavy first stage | |
| SpaceX | Merlin Vacuum | Liquid Oxygen/RP-1 | Falcon 9, Falcon 9 Heavy second stage | |
| SpaceX | Raptor (rocket stage) | Liquid Oxygen/Liquid Hydrogen | As of July 2009, some preliminary concept work was being done. |
Read more about this topic: List Of Private Spaceflight Companies