SpaceX Kestrel


SpaceX Kestrel
SpaceX Kestrel engine2.gif
SpaceX Kestrel
Country of originUnited States
First flight2006
Last flight2009
DesignerTom Mueller
Applicationupper stage boost
Liquid-fuel engine
PropellantLOX / RP-1
Cyclepressure fed
Thrust (vac.)6,900 pounds-force (31 kN)
Thrust-to-weight ratio65
Chamber pressure135 pounds per square inch (930 kPa)
Isp (vac.)317 seconds (3.11 km/s)
Dry weight52 kilograms (115 lb)
Kestrel engine test firing.

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.

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 is ablatively cooled in the chamber and throat and radiatively cooled in the nozzle, which is 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.[4] Helium pressurant efficiency is substantially increased via a titanium heat exchanger on the ablative/niobium boundary.[5]

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.

Kestrel 2

Enhancements to the design of the original Kestrel engine were planned, called the Kestrel 2.[6]

The engine design was still pressure-fed, and was supposed to fly on a newly designed second stage that used Aluminium-lithium alloy 2195, rather than the 2014 Aluminum used in the Falcon 1 second stage.[6] Engine changes were to include tighter tolerances to improve consistency, higher Isp, and lighter weight.[7] The Kestrel 2 did not remain in active development after the Falcon 1 was replaced by the much larger Falcon 9 v1.0 which used an improved Merlin 1C for its upper stage.

See also


  1. ^ "Falcon 1 Users Guide" (PDF). SpaceX. 2008-09-28. Archived from the original (PDF) on October 1, 2008.
  2. ^ - falcon
  3. ^ astronautix Archived 2013-12-16 at the Wayback Machine
  4. ^ Greg Zsidisin (23 March 2007). "SpaceX Confirms Stage Bump On Demoflight 2". Space Daily. Retrieved 2008-09-30.
  5. ^ "Falcon 1 Flight Three Press Kit" (PDF). SpaceX. Archived from the original (PDF) on 2008-10-01. Retrieved 2008-09-30.
  6. ^ a b Bjelde, Brian; Max Vozoff; Gwynne Shotwell (August 2007). "The Falcon 1 Launch Vehicle: Demonstration Flights, Status, Manifest, and Upgrade Path". 21st Annual AIAA/USU Conference on Small Satellites (SSC07 ‐ III ‐ 6). Retrieved 2013-12-06.
  7. ^ Bergin, Chris; Braddock Gaskill (2007-09-24). "Elon Musk Q and A - Updates SpaceX status on Falcon and Dragon". Archived from the original on 2008-05-29. Retrieved 2008-06-16.

External links

  • SpaceX Falcon engines page