RL10
The RL10 is a liquid-fuel cryogenic rocket engine built in the United States by Aerojet Rocketdyne that burns cryogenic liquid hydrogen and liquid oxygen propellants. Modern versions produce up to 110 kN (24,729 lbf) of thrust per engine in vacuum. Three RL10 versions are in production for the Centaur upper stage of the Atlas V and the DCSS of the Delta IV. Three more versions are in development for the Exploration Upper Stage of the Space Launch System and the Centaur V of the Vulcan rocket.
An RL10A-4 engine in London's Science Museum | |
| Country of origin | United States of America |
|---|---|
| First flight | 1962 (RL10A-1) |
| Manufacturer | Aerojet Rocketdyne |
| Application | Upper stage engine |
| Associated LV | Atlas Saturn I Titan IIIE Titan IV Delta III Delta IV DC-X (canceled) Space Shuttle (canceled) Space Launch System OmegA (canceled) Vulcan |
| Status | In production |
| Liquid-fuel engine | |
| Propellant | Liquid oxygen / liquid hydrogen |
| Mixture ratio | 5.88:1 |
| Cycle | Expander cycle |
| Configuration | |
| Nozzle ratio | 84:1 or 280:1 |
| Performance | |
| Thrust, vacuum | 110.1 kN (24,800 lbf) |
| Specific impulse, vacuum | 465.5 seconds (4.565 km/s) |
| Dimensions | |
| Length | 4.15 m (13.6 ft) w/ nozzle extended |
| Diameter | 2.15 m (7 ft 1 in) |
| Dry weight | 301 kg (664 lb) |
| Used in | |
| Centaur, DCSS, S-IV | |
| References | |
| References | |
| Notes | Performance values and dimensions are for RL10B-2. |
The expander cycle that the engine uses drives the turbopump with waste heat absorbed by the engine combustion chamber, throat, and nozzle. This, combined with the hydrogen fuel, leads to very high specific impulses (Isp) in the range of 373 to 470 s (3.66–4.61 km/s) in a vacuum. Mass ranges from 131 to 317 kg (289–699 lb) depending on the version of the engine.