<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I right clicked the pdf and saved it to my desktop, it opened then, however there is no author info, comments, signatures etc for it. I swear though the damn thing looks familar, I'm sure I've seen it or something very similar somewhere else, I just can't figure out where that somewhere is. The gif has no info either on it. Anyone want to email a copy to SpaceX and see what they say about it? <br /> Posted by windnwar</DIV></p><p>(1) The very first thing I said about this chart is that it is <u><strong>pure fiction</strong></u>. You should believe me! </p><p>(2) This work of <u><strong>fan fiction</strong></u> depicts a logical and plausible progression of SpaceX's heavy lift launch system. It is LOGICAL to want to replace nine Merlins with one larger engine because regardless of that engine's higher cost, its parts count will ensure that it is cheaper to build than nine small engines. The whole "engine out" capability marketing talk is just that... marketing talk. The reason SpaceX uses nine Merlins is simple. The quickest way to become a credible player is to reach orbit with something -- anything. And a single engine, two stage Falcon 1 is the simplest practical way to do it. Once they have done that, the most capitally frugal and schedule expedient way to put an Atlas V class payload into orbit is to use whatthey have got. And, what they have got happens to be the flight proven Merlin so they use it even if it takes nine of them.</p><p>(3) Why Griffon? Well, that is rooted in ancient history. You see, SpaceX named their two current engines Krestel and Merlin respectively. Both are names adopted by Rolls-Royce for their high performance V-12 aircraft piston engines in the pre-war years and during WWII. The Krestel is the smallest at 21 liters and was even used by the earliest Messerschmitt BF-109 development aircarfts before it went to the Daimler-Benz DB601. The 26 liter Merlin arrived later and eventually powered such illustrious aircrafts as the Spitfire and the Mustang. So what's next? By late WWII the Spitfire Mk.XIV got a boost in power in form of the 36 liter 2,400hp Rolls-Royce Griffon. If it is more than co-incidence that SpaceX named their engines Krestel and Merlin, then logically the next name in that sequence is the Griffon! </p><p>(4) The stated Falcon 9 LEO launch mass assumes a typical 500~600km orbit at 50~60 degrees (eg. ISS orbit), with sufficient upper stage reserve for circularization. 8.7 tons is about right given that the capacity to this altitude and attitude is 9.2 tons w/o circularization reserves. The Falcon 9 will lift less to a polar orbit and more to a near equatorial orbit. It will also lift more if you only want to get to minimum 185km LEO altitude. This is true of every rocket in the world. Actual payload capacity really depends on the mission! As a matter of fact, this is all academic at this point because the Falcon 9's current payload adapter and handling system limits practical payloads to 6.8 tons (excluding the fairing) regardless of the vehicle's kinematics.</p>