My first stab at a real Falcon Heavy page, after holding out for a while. www.spacelaunchreport.com/falconH.html Comments and criticisms welcomed, because I expect to edit this page substantially this year. I expect to be surprised when the thing rolls out and we actually see it for the first time. I also expect to be surprised by how SpaceX actually uses the machine. - Ed Kyle
Crossfeed has been put on the back burner and I wouldn't cover barge for boosters. I don't think that will be needed, the difference between pad and barge would be in the overall noise.
Quote from: Jim on 02/23/2015 08:14 pmCrossfeed has been put on the back burner and I wouldn't cover barge for boosters. I don't think that will be needed, the difference between pad and barge would be in the overall noise.While crossfeed may not appear for awhile, if ever, I'll have to include it as a future possibility as long as SpaceX continues to talk about 53 tonnes to LEO and 21.2 tonnes to GTO, since those are crossfeed (fully expendable) numbers.My guess is that the booster flyback recovery will usually be attempted, but that core recovery attempts (even downrange) may be less frequent because making the core expendable seems to double beyond LEO payload capacity, but I'm just guessing. - Ed Kyle
How would prop densification and thrust increase improve FH GEO payload with RTLS ?
Quote from: macpacheco on 02/23/2015 10:34 pmHow would prop densification and thrust increase improve FH GEO payload with RTLS ?I strongly suspect that the FH performance figures already take this thrust upgrade into account.
Ed's article implies an (uprated?) Merlin 1D in the offing, yet I thought the 1D has been flying for some time now in its "final" form. Is there in fact an uprated version of the 1D yet to fly?
I've been looking at Falcon Heavy possibilities a bit. The main puzzle is, and has long been, the SpaceX statement that the Heavy GLOW is 1,463 tonnes, while Falcon 9 v1.1 GLOW is only 506 tonnes. If you put Falcon 9 v1.1 pieces together as a first guess to build a Heavy, you only get a GLOW of 1358 tonnes or so. But even that rocket can get 45 tonnes to LEO and more than 15 tonnes to GTO in expendable mode (no crossfeed is assumed for any of my figuring right now). If the boosters and cores are recovered, and if 35 tonnes of recovery propellant is assumed for each, the numbers drop to 26 tonnes LEO and a bit more than 7 tonnes GTO, the latter of which lines up well with the 6.4 tonnes advertised capability. Expending the core but recovering the boosters gives 34 tonnes LEO and 11 tonnes GTO.That missing 100 tonnes GLOW could be packed into the rocket in several ways. One guess was that the boosters would be stretched a bit to carry more propellant than the core stage, which works out to improve the beyond-LEO expendable numbers a bit (GTO goes up to 17 tonnes full expendable, but is still only 8 tonnes or so for full recovery). Propellant densification could increase the mass of all three cores with similar results.So there is my thinking at present, all in flux.Now, about prices and costs, note that the current going rate to GTO is about $20 million per tonne. Thus, SpaceX would seem to be giving up $160 million of potential income when it recovers all three cores rather than expending them. Do three core stages cost more than $160 million? - Ed Kyle
Out of curiosity, what have you included as variables in your simulations?
Ed, is that's with Merlin-1D at 85% or 100%? There has also talk that S2 has been flying with propellant offload on F9 1.1.. Could that be part of the mass delta?
That missing 100 tonnes GLOW could be packed into the rocket in several ways. One guess was that the boosters would be stretched a bit to carry more propellant than the core stage, which works out to improve the beyond-LEO expendable numbers a bit (GTO goes up to 17 tonnes full expendable, but is still only 8 tonnes or so for full recovery). Propellant densification could increase the mass of all three cores with similar results.
Seems like no one thing accounts for the full 100 tons, but if you combine all three (propellant densification, booster stretch, increased S2 loading) you might get pretty close?
Quote from: cscott on 02/25/2015 06:55 amSeems like no one thing accounts for the full 100 tons, but if you combine all three (propellant densification, booster stretch, increased S2 loading) you might get pretty close?The S2 not launching full on F9 is just forum speculation, and non-sensical forum speculation at that. Don't believe it.
One guess was that the boosters would be stretched a bit to carry more propellant than the core stage