Draco (rocket engine family)

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Draco
Draco In-space Firing.png
A SpaceX Dragon spacecraft approaching the International Space Station fires one of its 18 Draco thrusters.
Country of origin United States
Manufacturer SpaceX
Application Reaction control system
Liquid-fuel engine
Propellant N2O4 / MMH[1]
Performance
Thrust (vac.) 400 N (90 lbf)[1]
Used in
Dragon (spacecraft)


Draco is a family of hypergolic liquid rocket engines designed and built by SpaceX for use in their launch vehicles and space capsules. Two engines have been built to date: Draco and SuperDraco.

A Draco thruster is a small rocket engine for use on the Dragon spacecraft,[2] as well as on the upper stages of the Falcon 9[3] and Falcon Heavy rockets, to provide for spacecraft attitude control in the vacuum of space.

SuperDraco rocket engines utilize the same storable (non-cryogenic) propellant as the small Draco thrusters, but are over 100 times larger in terms of delivered thrust. The much larger Super Draco engines will be used on later versions of the Dragon spacecraft to provide launch-escape capability on crew transport flights to low-Earth orbit, as well as entry, descent and landing control of the proposed Red Dragon robotic probe to Mars.

Draco[edit]

Draco thrusters generate 400 newtons (90 pounds-force) of thrust using a storable propellant mixture of monomethyl hydrazine fuel and nitrogen tetroxide oxidizer. The Draco thrust is comparable to the Marquardt R-4D engine developed for the Apollo Service and Lunar Modules in 1960s and used for apogee/perigee maneuvers, orbit adjustment, and attitude control.

Eighteen Draco thrusters are used on the Dragon spacecraft for attitude control and maneuvering.[1] This system is dual-redun­dant in all axes: any two can fail and still have complete vehicle control in pitch, yaw, roll and translation.

Four Draco thrusters are used on the Falcon 9 second-stage as a reaction control system.[3]

SuperDraco[edit]

Main article: SuperDraco
SuperDraco
SuperDraco test (KSC-2012-1208).jpg
SuperDraco firing at full thrust
Country of origin United States
Manufacturer SpaceX
Application LAS (Launch Abort System), powered landing[4]
Status Development
Liquid-fuel engine
Propellant N2O4 / MMH[5]
Performance
Thrust (vac.) 73 kN (16,400 lbf)[6]
Isp (SL) 235s [6]
Burn time 25 seconds [6]
Propellant capacity 1,388 kg (3,060 lbs)[5]
Used in
Dragon V2, DragonFly test vehicle

On February 1, 2012 SpaceX announced that it has completed the development of a new, more powerful version of a storable-propellant rocket engine, this one called SuperDraco. This high-thrust hypergolic engine—about 200 times larger than the Draco RCS thruster hypergolic engine—offers deep throttling ability and just like the Draco thruster, has multiple restart capability and uses the same shared hypergolic propellants. Its primary purpose is for SpaceX's LAS (launch abort system) on the Dragon spacecraft. According to the NASA press release, the engine has a transient from ignition to full thrust of 100 ms.[7] During launch abort, eight SuperDracos are expected to fire for 5 seconds at full thrust. The development of the engine is partially funded by NASA's CCDev 2 program.

SuperDracos will be used on both the Dragon V2 crew- and cargo-transporting space capsule as well as on the DragonFly (rocket), a prototype low-altitude reusable rocket that will be used for flight testing various aspects of the propulsive-landing technology. While the engine is capable of 73,000 newtons (16,400 lbf) of thrust, during use for DragonFly testing, the engines will be throttled to 68,170 newtons (15,325 lbf) to maintain vehicle stability.[6]

SuperDraco engines are capable of being restarted many times, and have the capability to deeply reduce their thrust providing precise control during propulsive landing of the Dragon capsule.[8]

As of 2012, SuperDraco is the second most powerful engine developed by SpaceX, approximately 200 times[7] more powerful than the Draco thruster engines. By comparison, it is more than twice as powerful as the Kestrel engine that was used in SpaceX's Falcon 1 launch vehicle second stage, and about 1/9 the thrust of a Merlin 1D engine.

In addition to the use of the SuperDraco thrusters for powered-landings on Earth, NASA's Ames Research Center is studying the feasibility of a Dragon-derived Mars lander for scientific investigation.[4] Preliminary analysis indicates that the final deceleration will be within the retro-propulsion SuperDraco thruster capabilities.[4][9]

See also[edit]

References[edit]

  1. ^ a b c "SpaceX Updates — December 10, 2007". SpaceX. 2007-12-10. Archived from the original on 2011-01-04. Retrieved 2010-02-03. 
  2. ^ "SpaceX Draco Thruster Performs Long-Duration Firing and Restart" (Press release). SpaceX. December 9, 2008. Retrieved July 17, 2014. 
  3. ^ a b "Falcon 9 Launch Vehicle Payload User’s Guide, 2009". SpaceX. 2009. Retrieved 2010-02-03. 
  4. ^ a b c NASA; SpaceX (October 31, 2011). "Red Dragon" (PDF). 8m.net. Retrieved 2012-05-14. 
  5. ^ a b "Finding of No Significant Impact (FONSI) and Record of Decision (ROD)". Federal Aviation Administration. March 5, 2014. Retrieved July 17, 2014. 
  6. ^ a b c d James, Michael; Salton, Alexandria; Downing, Micah (November 12, 2013), Draft Environmental Assessment for Issuing an Experimental Permit to SpaceX for Operation of the Dragon Fly Vehicle at the McGregor Test Site, Texas, May 2014 – Appendices, Blue Ridge Research and Consulting, LCC, p. 12 
  7. ^ a b "SpaceX Test Fires Engine Prototype for Astronaut Escape System". NASA. 2012-02-01. Retrieved 2012-02-01. 
  8. ^ "SuperDraco Thruster Powers Revolutionary Launch Escape System (Rocket Thruster Test)". Satnews Daily. 2014-05-27. Retrieved 2014-05-28. 
  9. ^ NASA Ames Research Center (1 November 2011). "NASA ADVISORY COUNCIL (NAC) - Science Committee Report" (PDF). Retrieved 2012-05-01. 

External links[edit]