This may seem obvious to some, but I don't think it actually can launch 53 tons to LEO.. it's just a reference orbit. That said, the best number I've seen for the fairing mass is 1,750 kg, so if you really want to squeeze a maximum payload to LEO number out of the Falcon Heavy you could probably imagine a payload that doesn't need to go inside the fairing (like some mega-Dragon). Also, this is all old numbers with cross-feed. Maybe this year SpaceX will release a press kit and we'll actually find out what the real vehicle on the pad can do.
How close to the cross-fed enabled 53mt payload to LEO is the non-cross-fed fully expended full thrust falcon heavy? I'm guessing it's fairly close...
Quote from: yokem55 on 12/30/2015 02:16 pmHow close to the cross-fed enabled 53mt payload to LEO is the non-cross-fed fully expended full thrust falcon heavy? I'm guessing it's fairly close...This may have changed, but last I heard there were 3 flavors of Falcon Heavy:1) Fully expendable, cross-fed: 21mt GTO, 53mt LEO2) Reusable boosters RTLS, expendable center core, cross-fed: 14mt GTO3) All 3 first stages RTLS, not cross-fed: 7mt GTOOf these, I believe 3) will be most important, as it covers virtually all current comsats with a fully reusable set of first stages that RTLS. If refurbishing the stages is relatively easy, as SpaceX suggests, then this configuration should end up being less expensive than an expendable Falcon 9.
The item not discussed is that your options is based on FHv1.1 performance and not the additional 33% that is a possible increase provided by a FHFT.
And even if the original numbers were for the reduced-thrust version of M1D, your 33% scaling factor is way too high for the payload increase for that 15% engine thrustupgrade.
Quote from: hkultala on 12/31/2015 07:21 amAnd even if the original numbers were for the reduced-thrust version of M1D, your 33% scaling factor is way too high for the payload increase for that 15% engine thrustupgrade.Much of the performance increase is in the upper stage enlargement and the larger M-vac nozzle.
Larger M-vac nozzle? where is this information from?
And upper stage enlargement helps payload to higher orbits more than payload to LEO. 30% increase in GTO payload may mean 24% increase in LEO payload.And, if spaceX knew they were going to expand the second stage again before FH, I think the effect of this is already calculated in the original FH capasity numbers.
Has SpaceX said anything about engine out capability with reuse?
Even though they released the 53t number many years ago, they already knew then what their M1D will finally be capable of.
Although an engine out may not leave enough fuel for RTLS I don't think it is a certainty. If the engine out occurs late during first stage flight then it may leave enough fuel to still make it back. Beyond that, I don't think there is fine grained enough monitoring of the fuel level to decide if there is enough to make it so the computer will likely just try to land and if fuel runs out during one of the three burns then the rocket drops either just off shore or on the landing pad. Even with a hard landing I bet SpaceX would love to get back a failed engine to figure out what went wrong with it.
FH will be manrated like F9FH's first version will be based on F9v1.1FT but will upgraded in the future.Probably they will use more composites to save weight, introduce crossfeed and first stage engines that do not dump the exhaust from the turbopumps. (like the merlin 1D vac from s2)