Even though propane might be a great rocket fuel. I believe methane might be a safer option.
baldusi, where did you get the value of 44,178kg for RP-1 US? The values I dug up in an old NASA report showed max propelant loads of 27600 L of LOX or ~31,491kg and 17,400 L of RP-1 or ~ 19,853kg for a total of 51,345kg for the current F9 US.
NASA has no need to pay for the Grashopper RLV.
Quote from: Jim on 10/06/2011 04:54 pmNASA has no need to pay for the Grashopper RLV. bet part of the LAS program pays for the Grashopper RLV.
What we had said, was that the cost of development for an engine like the RD-191 was simply too much for the extra performance, given SpaceX's cost consciousness. But since they have stated that they are working an a "super efficient staged combustion" rocket engine, it's clear that they have found a way to develop it at a reasonable cost.
Far more likely is the idea that the new SC engine will have a chamber pressure similar to Merlin 1D, it'll have a very good ISP due to SC and the large expansion nozzle, and a mediocre T/W that will be acceptable on US engines.
If you look at Merlin 1D, its chamber pressure is still nowhere near the better Russian engines. They cut a lot of weight leading to an excellent T/W, but it makes no sense for them to do this if they are both capable of matching the Russians, and of a mind that it is economical to do so. If they were willing and able to do so, 1D would be better than it is.
I've no doubt it's operationally simpler for SpaceX to have the same fuel and similar engines on both stages, but the fact is they had to build a complete rocket on a relative shoestring and that contributed to their design decisions. Now they have real cash flow and much larger first stages to deal with, and that can quite easily lead to different decisions than before.
They are not able to match the Russians. At least they are not in an RP-1 engine.
Please remember, the Merlin 1D was their first turbopump.
A quick search came up with this, although this is NOT listed on their site. http://www.startuphire.com/job/turbo-pump-designer-hawthorne-ca-spacex-147175
Quote from: krytek on 10/09/2011 10:24 pmA quick search came up with this, although this is NOT listed on their site. http://www.startuphire.com/job/turbo-pump-designer-hawthorne-ca-spacex-147175I've definitely seen turbopump designers on the SpaceX website a while ago.
I'll ask again. Does that prove they are actively building their own M1d turbopumps?This is how rumors and unconfirmed information turns into a "fact" later.