Author Topic: Discussion/Comparison of the new generation of American heavy lift launchers  (Read 73996 times)

Offline ioncloud9

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So to build a decent upper stage for SLS would require another billion or so dollars.  IF, NASA instead gave SpaceX 1/3 of this money for a 5.2m Metholox upper stage, the same length as the existing stage.  And IF, NASA gave 1/3 of this money to Blue Origin to develop their 3 stage New Glenn.  And IF, NASA gave ULA 1/3 of this money to develop ACES.

Then Congress would take it away and give it back to Boeing.

NASA would NEVER fund a methalox upper stage. Since on orbit refueling isn't part of their calculation, they only see value in ISP and efficiency. Hydrolox is king here. Plus fuel can be simply made on the moon with water ice for hydrolox.

SpaceX has a methalox upper stage for 2 important reasons. First, it greatly simplifies the entire launch system by having 1 fuel type. It simplifies engine design to have 1 family of rocket engines, simplifies pipes, vehicle and booster design because the ratios are the same, fueling, launch pads etc. This is such a big benefit, SpaceX does this with the even less efficient fuel kerolox for Falcon 9. These benefits are unimportant to NASA and would be a detriment to SLS since it would go from an entirely hydrolox vehicle to a mixed fuel system.

The second reason is methalox can be made easily on Mars. Starship is planning to land on Mars and fly back so having a methalox stage is an advantage. This is also unimportant to NASA since its decades away in their mind and they wouldn't plan to use the upper stage that sends a ship to Mars to actually land on it.

Offline GWH

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45 tonnes to TLI with Block 1B now being claimed

Offline spacenut

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This topic was started a couple of years ago.  When this topic was started, I don't think even Falcon Heavy had launched yet. 

Looks like Starship is being developed fairly fast (Old BFR).  Starship may be launched before SLS at the rate everyone is progressing. 

BE-4 is the long pole on both Vulcan and New Glenn as to when both will be ready.  Vulcan may be coming along.

OmegA seems to have fallen by the wayside. 

SLS, still at a snails pace.  So is Vulcan and New Glenn. 

Looks like F9/FH and Atlas V are the workhorses for now.  Delta IV heavy is having it's problems. 

Offline su27k

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Yes, when this thread started, neither F9 Block 5 nor FH has launched yet. Now both has entered service and fulfilled their promise. The others? Not so much. Everyone else seems to be slipping year by year, with Omega gone all together.


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