Comment: Space X Merlin 1D is not quite the “most efficient” rocket engine ever

by | Jun 26, 2012 | Commercial human spaceflight, commercial launch services, Seradata News, SpaceX | 6 comments

On the successful firing of its Merlin 1D engine, Space Exploration Technologies, with more than a note of self congratulation, states that the “enhanced design makes the Merlin 1D the most efficient booster engine ever built” further noting that it has “a vacuum thrust-to-weight ratio exceeding 150”,

True – it has the best ever thrust-to-weight ratio, taking this record from the Russian NK-33 (now made under the US designation AJ-26).  However, for most rocket engineering cognoscenti, it is specific Impulse, the momentum change per kg of propellants used, that is the true measure of rocket efficiency. 

As such, with its “open” gas generator cycle and using the propellants of LOx (liquId oxygen) and kerosene, the Merlin 1D will never match the efficiencies of the LOX/Liquid hydrogen powered  Vinci or RL-10 engines.  Under this measure, at circa 310 seconds, the Merlin 1D’s vaccuum specific impulse is about a third less than the 465 seconds or so that these expander cycle engines can manage. 

And if you really want to be a trouble maker you could mention electric ion thrusters whose vaccuum specific impulses are measured in the thousands of seconds – albeit with very low thrust.

About Seradata

Seradata produces the renowned Seradata database. Trusted by over 100 of the world’s leading Space organisations, Seradata is a fully queryable database used for market analysis, failure/risk assessment, spectrum analysis and space situational awareness (SSA).

For more information go to https://www.seradata.com/product/

Related Articles

Categories

Archives

Tags

nasaspacexecoreviewsissesaArianespacevideochinaFalcon 9v1.2FT Block 525virgin galacticULAfalcon 9evaRoscosmosspacewalkDGAaviation weekBlue OriginInternational Space StationaresIGTsoyuzRocket LabBeidouawardsStarlinkspaceAirbus DSboeingSatellite broadcastingrussiamoonOneWebISROCargo Return VehiclemarsblogresearchspaceshiptwoorionjaxamarsimpactdelayhyperbolaEutelsatdemocratrocketlunarhypertextobamagoogle lunar prizelaunchVegathales alenia spaceSESconstellationtourismbarack obamafiguresnorthspaceflightIntelsatnode 2fundedRaymond Lygo2009Lockheed MartinExpress MD-2Elon MuskAtlas Vromess2dassault aviationsstlaviationLucy2008wk2ukradiosuborbitaltestmissiledocking portexplorationAriane 5 ECAVirgin OrbitinternetSLSLong March 2D/2ElectronNorthrop GrummanChina Manned Space Engineeringsts-122Ariane 5missile defensenewspapercotsgalileospace tourismflight2010Long March 4CspaceportExpress AMU 1buildspace stationaltairsoyuz 2-1aProton Minternational astronautical congressshuttlespace shuttleAriane 6scaled compositesIntelsat 23European Space AgencyLauncherOneCosmoshanleybudgetrulesnew yorkatvVietnamshenzhoucongressMojaveboldennew shepardLong March 2CInmarsatOrbital ATKcnesiaclunar landerGuiana Space CenterApollolawsUS Air ForceSpace Systems/LoralUK Space AgencyLong March 4BKuaizhou 1AkscprotonILSdarpaTalulah RileyVega CElectron KSFalcon 9v1.2 Block 5North KoreaeuSkylonAstriumlanderbaseusaastronautdragonpicturefiveeventTelesatSSLAprilSNC50thinterviewSea LaunchLong MarchfalconWednesdaycustomerlinkatlantissuccessor

Stay Informed with Seradata

Stay informed on the latest news, insights, and more from Seradata by signing up for our newsletter.