SpaceX Kestrel
The SpaceX Kestrel was an LOX/RP-1 pressure-fed rocket engine. The Kestrel engine was developed in the 2000s by SpaceX for upper stage use on the Falcon 1 rocket. Kestrel is no longer being manufactured; the last flight of Falcon 1 was in 2009.
SpaceX Kestrel | |
| Country of origin | United States |
|---|---|
| First flight | 2006 |
| Last flight | 2009 |
| Designer | Tom Mueller |
| Manufacturer | SpaceX |
| Application | Upper stage boost |
| Liquid-fuel engine | |
| Propellant | LOX / RP-1 |
| Cycle | Pressure fed |
| Performance | |
| Thrust, vacuum | 28 kN (2.9 tf) |
| Thrust-to-weight ratio | 65 |
| Chamber pressure | 9.3 bar (135 psi) |
| Specific impulse, vacuum | 317 seconds (3.11 km/s) |
| Dimensions | |
| Dry weight | 52 kg (115 lb) |
| References | |
| References | |
Kestrel was built around the same pintle architecture as the SpaceX Merlin engine but does not have a turbopump and is fed only by tank pressure.
Kestrel was ablatively cooled in the chamber and throat and radiatively cooled in the nozzle, which was fabricated from a high strength niobium alloy. As a metal, niobium is highly resistant to cracking compared to carbon-carbon. According to SpaceX, an impact from orbital debris or during stage separation might dent the metal but have no meaningful effect on engine performance. Helium pressurant efficiency is substantially increased via a titanium heat exchanger on the ablative/niobium boundary.
Thrust vector control is provided by electro-mechanical actuators on the engine dome for pitch and yaw. Roll control (and attitude control during coast phases) is provided by helium cold gas thrusters.
A TEA-TEB pyrophoric ignition system is used to provide multiple restart capability on the upper stage. In a multi-manifested mission, this design would allow for drop off at different altitudes and inclinations.