Phase I only refers to Atlas. There is no comparable "phasing" for Delta IV
Quote from: Jim on 07/02/2009 12:48 amPhase I only refers to Atlas. There is no comparable "phasing" for Delta IVThere's a combined set of phases in ULA's presentation to the Augustine commission. Phase 1 appears to be a new common upper stage.
snipWhat am I missing that makes cryo fuel transfer so scary?
Come to think about it, I didn't see the Delta data use the term Phase I? But they did have a nice chart of future growth. 50t looks like a reasonable number for an upgraded Delta.
Do you know what the mass to LEO is for a Phase I Atlas Heavy?
I haven't found Phase I for the Atlas. I am leaning to this 50t to LEO for lunar missions.
Spinning will not work, because the fuel is on both sides of the c.g.
A settling rocket would, but I don't think it has ever been done. The smaller the rocket, the smaller the flow rate. Rockets take a lot of design work and use prop.
Cryo can not use diaphragms.
Cryo transfer takes lots of work on how the lines react to the cold. Liquid Hydrogen has a history of being a pain in the butt to handle.
It is a high risk development. Could it be done with enough time and money? Yes. The whole point of this effort is to minimize risk and development dollars.
50mT could be just enough to get an Orion to L1 in one launch, provided it doesn't get much heavier. That's a potentially interesting mission scenario in itself, provided you have something to do there. Radiation experiments are my standby example.Topping up Orion propellant from a depot would help even if performance turns out to be less or if Orion turns out to be heavier, but then you lose some of the benefit of single-launch. Staging at L2 and using 12 day trajectories should be possible even without refueling, though without an Altair I'd be wary of doing that. It would likely also make for a harder sell, especially since some will no doubt seize on this.
Spinning will not work, because the fuel is on both sides of the c.g.Liquid Hydrogen has a history of being a pain in the butt to handle.
For these reasons LOX is the low-hanging fruit so the first cryo propellant transfer should transfer LOX only. Don't discount LOX transfer just because LH2 transfer is hard! Launch the EDS with empty LOX tank but full LH2 tank.