Quote from: Downix on 05/27/2011 06:19 amDon't see how they can plan on getting the listed performance with only 2 stages.Why not? The RAC-2 team seems to think it can hit some pretty impressive numbers with 2 stages.
Don't see how they can plan on getting the listed performance with only 2 stages.
I haven't seen it. But then again, that might just be because SpaceX would much rather sell Nasa a Falcon X
Quote from: madscientist197 on 05/27/2011 01:56 pmI haven't seen it. But then again, that might just be because SpaceX would much rather sell Nasa a Falcon XAnd why would SpaceX prefer to sell them a Falcon X over this? Would they make more money on a Falcon X because Falcon X is cheaper to develop, manufacture, and operate?This thread implies that SpaceX missed something obvious with Falcon X, and implies that a 5/7 lego core vehicle is better than what SpaceX has planned to meet this lift class.
Has anyone brought up, if SpaceX though they could get to Heavy lift by going to five or seven cores, would they have not included it in growth options they have presented in the past?Or did I miss the powerpoint?
I didn't read through the whole thread to see if anybody brought this up already, buuut, I don't think you can get a big enough faring on a 3.6 meter body to make 80 or 90 metric ton lift ability worth it.
Quote from: Halidon on 05/27/2011 07:20 amQuote from: Downix on 05/27/2011 06:19 amDon't see how they can plan on getting the listed performance with only 2 stages.Why not? The RAC-2 team seems to think it can hit some pretty impressive numbers with 2 stages. They also use high energy fuel. SpaceX does not.
Quote from: Michael Bloxham on 05/26/2011 07:05 pmPerhaps we could solve both of these via a 6-core variant - with the centre core being a strengthened and lengthened version of falcons current (air-lit) upper stage? I.e. a strengthened core with a Merlin Vacuum on the end of itWell, if you take a normal core, and put a single Merlin Vac, and then strap two Falcon Heavies to the side, you'd get a center with dual US in series, and two Heavies core plus boosters on the side. It would have something like four effective stages. And the separation issue is simplified since you can join the four boosters in pairs and separate them together. You'd have 33.63N, or 3,429mT of thrust. It should weight something around 3,000mT.Of course that the fairing has something like 125m³, so you could potentially put a lot of water, concrete or lead in LEO. But anything significantly bigger, would be a problem.
Perhaps we could solve both of these via a 6-core variant - with the centre core being a strengthened and lengthened version of falcons current (air-lit) upper stage? I.e. a strengthened core with a Merlin Vacuum on the end of it
The first one is not viable.
Just make a fat upper stage.
It would be smarter to instead develop the Falcon-X and Raptor than all of this. Once you have those, the Falcon-X heavy would be able to handle missions up to the weight range, while scaling down to the more common payload sizes.
Quote from: Downix on 05/27/2011 04:21 pmIt would be smarter to instead develop the Falcon-X and Raptor than all of this. Once you have those, the Falcon-X heavy would be able to handle missions up to the weight range, while scaling down to the more common payload sizes.PLF size is still limiting in this case though. Unless you can find a sensible way of distributing PLF loads through the outer CCBs through Max Q while allowing their later separation?Y'know what? Maybe the best solution to that problem would be to simply eliminate the cross-feed and have all three CCBs burn out at the same time. Like Delta IV Heavy and also your Delta IV 7xCBC Super Heavy concept. Three Falcon 9 Upper stages would be tied together to form the upper stage - allowing a very large PLF to be supported through Max Q. Essentially just three Falcon 9's tied together. For the Super Heavy, tie 5 or 7 of them together - Mike
Quote from: Michael Bloxham on 05/27/2011 04:44 pmQuote from: Downix on 05/27/2011 04:21 pmIt would be smarter to instead develop the Falcon-X and Raptor than all of this. Once you have those, the Falcon-X heavy would be able to handle missions up to the weight range, while scaling down to the more common payload sizes.PLF size is still limiting in this case though. Unless you can find a sensible way of distributing PLF loads through the outer CCBs through Max Q while allowing their later separation?Y'know what? Maybe the best solution to that problem would be to simply eliminate the cross-feed and have all three CCBs burn out at the same time. Like Delta IV Heavy and also your Delta IV 7xCBC Super Heavy concept. Three Falcon 9 Upper stages would be tied together to form the upper stage - allowing a very large PLF to be supported through Max Q. Essentially just three Falcon 9's tied together. For the Super Heavy, tie 5 or 7 of them together - MikePrecisely. Perfection is the enemy of good enough. Cross-feed is a novel technique, and gives benefit, but also adds complexities, costs, and risks. The elimination of it would render the design good-enough, and as a result you would have the power you need, and can dial-a-rocket.
You've developed the Saturn I.
Quote from: baldusi on 05/27/2011 05:45 pmYou've developed the Saturn I.Bingo. The Delta SuperHeavy is also a Saturn I. I figure, if it works, why mess with it?