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SpaceX SHOULD have been flying Starship to orbit 4 years ago, no SuperHeavy required:
http://exoscientist.blogspot.com/2023/0 … heavy.html
Robert Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
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RGClark,
Firing 3 to 6 engines at once using the upper stage can only tell them so much. It's a far cry from the booster's 33 engines.
What would flying the upper stage to orbit actually tell them about the booster's design issues or lack thereof?
Starship Super Heavy is not primarily intended to be flown as a SSTO, even if it can do it. That is your project, not SpaceX's project. They're designing / testing / flying to meet their own criteria.
Apart from that, I agree with your assessment about conducting a full duration burn with all engines running, assuming that's feasible to do.
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Falcon Heavy flies with 27 engines burning simultaneously. Of course, those are the smaller Merlins, not the bigger and newer Raptors, and now there is a huge experience base with those engines. I honestly don't know if they static fire all 27 Merlins at once when they launch a Falcon Heavy. I think they fire all 9 at once briefly, for a Falcon-9 launch static test.
What SpaceX had in mind with the Starship/Superheavy design was twofold: (1) they wanted to scale up the Falcon-9 first stage operational concept to a much larger size, and (2) they wanted to eliminate the payload fairing and expendable second stage concept in favor of a recoverable cargo-carrying spacecraft as the second stage.
That second item is the thing not ever done before, especially at such a large scale, and it's essentially all a brand-new development effort. The notion of just scaling up the Falcon first stage core was to eliminate most of the development effort, but I think they were surprised by all the related issues (such as noise and explosion risks) that the large size causes.
Just goes to show that you can't be right about everything, no matter who you are or what your public image might be.
As for SSTO concepts using only the Starship second stage, fully loaded it is in the 1400 metric ton class. 6 sea level Raptors at about 200-220 metric tons-force thrust each at sea level totals only 1200 to 1300 metric tons-force of thrust, not even enough to takeoff, and way short of the kinematic requirement of takeoff thrust/weight ~ 1.5.
There's no room back there for 8 or 9 or more such engines. You would need at least 9 or 10 of them to get to adequate takeoff kinematics. All that really says is that you needed to look at the SSTO option back when it was a clean sheet of paper design. It's way too late now.
Unless you can obtain some 350-400 ton-force engines that fit the same size envelope as the 200-220 ton engines, then you cannot adapt the hardware for SSTO operation. It'll never happen with the hardware on hand now.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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