SpaceX (general discussion)

Michel Van said:
The mass of Starship is 1330 tons (1200t prop + 130t empty) Vs thrust of 1250 tons.
The 3 sea level Raptors are inefficiency in vacuum.
Raptor 3 provide higher trust what compensated the gravity losses.
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If current Starship is 130t dry, with 30 ton in the headers as written in the March 2024 FAA environmental report, then even with 0 gravity losses on the S2 and running the Raptor SL as little as possible, with the IFT-2/IFT-3 separation speed, and considering that musk called "100 tons ship" as a long term goal, the current-size starship won't be able to launch more than 100 tons with its current propellant mass, going significantly above 100 tons requires a stretch and higher propellant mass. Which is what they're doing.

Note: The 70 tons of remaining propellant in the main tank mentioned in the March 2024 FAA environmental report seem compatible with "40-50 tons to orbit" considering the additional propellant needed to circularise from the IFT-3 trajectory.


Also , that "Starship 2" is really sexy with its more slender canard, slightly pointier nose and its russian-style strut interstage.
 
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Current interstage design is pretty clearly a temporary one, designed with ease of removal/installation for prototypes in mind, the simple fact that it's expendable (something which goes against SX' philosophy on Starship) should prove that.
 
Dagger said:
Look at that: the new vented interstages of Starship 2 and 3 have triangles / diagonals.

It seems Elon finally woke up and fired the idiot that designed the original monstrosity.
The bullies on this forum that attacked me in the past for pointing that out must feel pretty foolish now.
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Not one bit because it is an iterative design. You need to wake up. It is the same group of people doing the designs. You made the foolish claim it was going to fail. The existing design was overbuilt but easy and quick to manufacture and easy to modify. It was not poor design as far as structural integrity, only inefficient in that it was heavy and single use. Designing and manufacturing struts and the interstage rings would take time and would not be easy to change
 
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Dagger said:
Look at that: the new vented interstages of Starship 2 and 3 have triangles / diagonals.

View attachment 724985

It seems Elon finally woke up and fired the idiot that designed the original monstrosity.
The bullies on this forum that attacked me in the past for pointing that out must feel pretty foolish now.
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Disagreement isn’t bullying.
 
Byeman said:
You made the foolish claim it was going to fail.
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Emphasis on this.

It did not fail and the argument that it would inevitably fail based on a mistaken understanding of engineering and physics was therefore refuted.

Centuries before Dunning and Kruger, Alexander Pope:

A little learning is a dangerous thing ;
Drink deep, or taste not the Pierian spring :
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.
 
The important thing is that Musk isn't stingy---and supports an aggressive flight program not seen since the 1960's.

As a pessimist, I still can't half believe what is going on there. Iteration could come faster if he were allowed a free hand.

The same fish and wildlife people who made Elon's life misery? I understand they want to kill half a million barn owls.

If they are going to do that---then they have no business at all worrying about a few mockingbirds or whatever being immolated.
 
Byeman said:
....... The existing design was overbuilt but easy and quick to manufacture and easy to modify. It was not poor design as far as structural integrity, only inefficient in that it was heavy and single use. Designing and manufacturing struts and the interstage rings would take time and would not be easy to change
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Neither SpaceX nor you ever claimed that the present interstage design was for single use only.
You come up with that argument only now as you see that you were wrong in the past.

The present design used so far consists of some 300 pieces of metal welded together by some 9000 spot welds and other welds (excluding the heat shield), that is not easy and quick to manufacture.
That they had to modify the design after the test article by increasing the number of pieces from 170 to 300 is prove that amateurs were responsible for this design.

The new design consists of many identical struts, is therefore quick and easy to manufacture, and should have been used from the start. That should have been obvious to any real engineer or scientist.
 
Dagger said:
Neither SpaceX nor you ever claimed that the present interstage design was for single use only.
You come up with that argument only now as you see that you were wrong in the past.
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Right here.
The discussion wasn't about reuse but just making it through launch.
And it was to be jettisoned before splashdown.
Dagger said:
The present design used so far consists of some 300 pieces of metal welded together by some 9000 spot welds and other welds (excluding the heat shield), that is not easy and quick to manufacture.
That they had to modify the design after the test article by increasing the number of pieces from 170 to 300 is prove that amateurs were responsible for this design.
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That is wrong.
A. They have plenty of sheet metal workers and welders. It was quick to manufacture and modify. Spot welding is a fast process and cutting sheet metal is quick.
b. Struts would have required different manufacturing processes and would not have been adaptable to changes Any changes would require scrapping and starting over. A strut interstage is not conducive to an iterative design process. They are not iterating the exact design of the interstage but what is required of the interstage. Once they settle on the height and opening size, they can finalize the strut interstage. Adding 3 more engines and lengthening the upperstage is going to change the interstage "requirements" again. So a strut interstage for the vehicles that had flown would not have worked on later vehicles.
Dagger said:
The new design consists of many identical struts, is therefore quick and easy to manufacture, and should have been used from the start.
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Wrong. The interstages were different between flights. Not if they want to change strut length or diameter or spacing between test flights. And the rings that the struts attach to would even be harder to change. They don't know what the final design is going to be at this time.

Dagger said:
That should have been obvious to any real engineer or scientist.
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A real engineer would understand what SpaceX is doing and not make crazy clueless posts.
 
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Another day, another hassle of creating a TSTO - RLV on the "wrong" planet. One with an atmosphere so thick, sea-level engines and vacuum engines needs very, very different nozzles...
 
Forest Green said:
breakingdefense.com

Pentagon working with Ukraine, SpaceX to prevent Russian exploitation of Starlink - Breaking Defense

“Just the idea of this being more available and so people can find it and try to exploit it, that's something we just have to bake in and understand,” Assistant Secretary of Defense for Space Policy John Plumb said of commercial services like SpaceX’s Starlink constellation.
breakingdefense.com breakingdefense.com
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That will be a big help if the Russians can be stopped from using Starling in Ukraine. It would help if it can be determined how exactly the Russians have been obtain Starling terminals and blocking them from the Starling network.
 
If the stretch Starship were loaded with batteries/fuel cells or whatever---how much electrical power could it...deliver?

Any thought to drop tanks on Starship to lessen number of tiles?
 
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publiusr said:
Any thought to drop tanks on Starship to lessen number of tiles?
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None. Just stop. How many times does it have to be repeated. SpaceX's efforts are to reduce launch costs by developing a large 100% reusable vehicle. Actual Lift capability is secondary. They will adjust the vehicle size once they get reusability down.
 
publiusr said:
If the stretch Starship were loaded with batteries/fuel cells or whatever---how much electrical power could it...deliver?
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Depends on the amount of reactants/propellants delivered. Fuel cells can use NG and O2. Actual fuel cell mass is small. Radiators might be the mass and volume issue.
 
Byeman said:
How many times does it have to be repeated. SpaceX's efforts are to reduce launch costs by developing a large 100% reusable vehicle. Actual Lift capability is secondary. They will adjust the vehicle size once they get reusability down.
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The stretch Starship doing a belly flop worries me a bit.
I would think the more compact something is, the more hardy...better able to handle re-entry.

The longer Starship is--the easier it is to pop off tiles due to flexing.

What if the tiles tesselate one way, but have ridges that look like a Ford Tri-motor when assembled?

Perhaps a substance can be threaded through those and tied at the nose to make the TPS essentially one piece?
 
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publiusr said:
The stretch Starship doing a belly flop worries me a bit.
I would think the more compact something is, the more hardy...better able to handle re-entry.

The longer Starship is--the easier it is to pop off tiles due to flexing.

What if the tiles tesselate one way, but have ridges that look like a Ford Tri-motor when assembled?

Perhaps a substance can be threaded through those and tied at the nose to make the TPS essentially one piece?
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No, more compact doesn't have the propellant to do the mission.

Bigger is better. Means lower ballistic coefficient and hence a cooler entry.

Ridges won't work because the two attitudes the vehicle flies at are 90 degrees to each other.

Tying them doesn't help. There is no strength in the tiles.

SpaceX just needs to work on the mounting method. There is no rush. The vehicle has several test flights ahead to figure it out. And will be scores of flights before people return on it.
 
Byeman said:
Bigger is better. Means lower ballistic coefficient and hence a cooler entry.
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Touche'

The tiles themselves are not strong, but perhaps something besides the pins could be used.

The pattern here looks like something that could flex:
phys.org

Laser-patterned thin films that swell into kirigami-like structures offer new opportunities in hydrogel technology

New options for making finely structured soft, flexible and expandable materials called hydrogels have been developed by researchers at Tokyo University of Agriculture and Technology (TUAT).
phys.org phys.org

Perhaps a similar pattern can help unitize things somehow. This is meant for small applications of course---but that pattern may be of interest.
 
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publiusr said:
The pattern here looks like something that could flex:
phys.org

Laser-patterned thin films that swell into kirigami-like structures offer new opportunities in hydrogel technology

New options for making finely structured soft, flexible and expandable materials called hydrogels have been developed by researchers at Tokyo University of Agriculture and Technology (TUAT).
phys.org phys.org

Perhaps a similar pattern can help unitize things somehow. This is meant for small applications of course---but that pattern may be of interest.
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No, it needs to be simple and cheap
 
Forest Green said:
A nuclear reactor and generator would give a better electrical output and a sustained one too.
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That stretch Starship looks like it could hold this:
en.wikipedia.org

Chemical oxygen iodine laser - Wikipedia

en.wikipedia.org en.wikipedia.org

Maybe a subvariant that has special tankage that---when free of propellant--can use refueling tech to pump new chemicals in.
Maybe use those or other chemicals to keep an NR-1 type reactor going for the solid State laser added on at a later date ;)
 
Rhinocrates said:
Emphasis on this.

It did not fail and the argument that it would inevitably fail based on a mistaken understanding of engineering and physics was therefore refuted.

Centuries before Dunning and Kruger, Alexander Pope:

A little learning is a dangerous thing ;
Drink deep, or taste not the Pierian spring :
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.
Click to expand...
You have to know a lot to realize you really don't know as much as you thought you did.
 
publiusr said:
That stretch Starship looks like it could hold this:
en.wikipedia.org

Chemical oxygen iodine laser - Wikipedia

en.wikipedia.org en.wikipedia.org

Maybe a subvariant that has special tankage that---when free of propellant--can use refueling tech to pump new chemicals in.
Maybe use those or other chemicals to keep an NR-1 type reactor going for the solid State laser added on at a later date ;)
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You could call it. . .Zenith Star.
 
I was just struck with a thought---if this thing keeps being stretched out---with a hammerhead shroud and painted blue--it's going to wind up looking like Delta II on Steroids. At that size any SRBs will look tiny again...
 
publiusr said:
That stretch Starship looks like it could hold this:
en.wikipedia.org

Chemical oxygen iodine laser - Wikipedia

en.wikipedia.org en.wikipedia.org

Maybe a subvariant that has special tankage that---when free of propellant--can use refueling tech to pump new chemicals in.
Maybe use those or other chemicals to keep an NR-1 type reactor going for the solid State laser added on at a later date ;)
Click to expand...
That's honestly a crap laser compared to what can be done now. Fibre lasers and Metastable Rare Gas Lasers (MRGLs) are what give the best efficiencies. Zenith Star was to weigh ~40t. USNC were advertising a 10t 50MWth reactor. If we assume 10t for the laser and 10t for the generator and 10t for the rest of the satellite and a 40% generator effiency and a 50% laser efficiency (which is actually conservative for the best fibre lasers and MRGLs), you get an output of 10MW for the same size without the need to refuel it... well except once every 30 years maybe. ;)
 
publiusr said:
That stretch Starship looks like it could hold this:
en.wikipedia.org

Chemical oxygen iodine laser - Wikipedia

en.wikipedia.org en.wikipedia.org

Maybe a subvariant that has special tankage that---when free of propellant--can use refueling tech to pump new chemicals in.
Maybe use those or other chemicals to keep an NR-1 type reactor going for the solid State laser added on at a later date ;)
Click to expand...
The stretch Starship doesn't have anymore volume than the current one. It juat gets the payload mass to level they wanted.
 
launch Statistic

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