Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Wiki Super Heavy/Starship - General Development Discussion

This site may earn commission on affiliate links.
More shielding being installed around the OLM.

D0D340F2-1985-4CE6-9102-5F5921E61C96.jpeg
 
  • Like
Reactions: Grendal
Yes, and yes. The issue is that SS is WAAAY too big for anything but the mega-ist of constellations or big lift human based missions (which is its point) and so there's not going to be a huge external demand to buying a more expensive rocket even if it has more favorable mass-to-orbit economics.
Yeah, it may be overkill, but what numbers are you using to estimate that SS/SH is more expensive than a triple core, expended second stage, possibly expended center core, fairing recovery FH mission?
Starship propellant cost is around one million dollars.
 
  • Like
Reactions: Ben W and scaesare
  • Like
Reactions: Grendal
I misspoke. My understanding was that they were designed by the same team/project, which had worked on a variety of sizes from very small (fingers on Optimus) to very large (gimballing raptors.) But I may have misunderstood entirely.
Oh, I totally agree they look like they grew from the same team, was just clarifying that they were not of the size used on Optimus Sub-prime. Now Optimus Prime on the other hand 🤯...

But I suspect those modules would be pretty ideal for Starship-- More cubical and should fit in the places between the domes.
Between the domes? Are you referring to above the methane top dome and below the crew area?
 
Yeah, it may be overkill, but what numbers are you using to estimate that SS/SH is more expensive than a triple core, expended second stage, possibly expended center core, fairing recovery FH mission?
Starship propellant cost is around one million dollars.

First, while it would be inappropriate for me to talk actual numbers, I think it's fair to work this through public domain level info/speculation.

Second, I'd contest our disconnect is that I don't think you're asking the right question--few people are buying the enhanced F9's and even fewer who actually need it (Evidence: the super light SpaceForce! missions, the not-that-heavy Arabsat, etc), so using those enhanced variants maths' really doesn't address much market.

Near as makes no difference for an analogy, SS capacity is more or less that of a C5/AN-124. F9 capacity is more or less that of a 737 freighter. The aspiration for SS fully taking over SX launch duties comes down to an assumption of "build it and they will come"--that enough paying customers are going to want/use something WAY bigger than the 737 simply because its available. While certainly plausible, there's some major flaws in that logic. For instance: History has shown that for-profit companies are not going to spend more than they need to in their cost centers...so nobody's going to buy the Antonov when all they need is the 737. To that end, to date--and likely until SS becomes operational, its hard to imagine a material amount of top tier customers (= entities that are guaranteed to need launch services) will pivot their infrastructure toward something that needs a bigger-than-737

History has also shown that for-profit companies are reluctant to invest in their suppliers unless there's a really high probability of return, so those who could use SS the most (externally funded moonshot mega-constellations like AST) really have to play the game with respect to their investors--gotta get enough money to make it work but can't simply dump money into a supplier and hope-real-hard that it comes good...especially a supplier like SX who is obviously driven by internal aspirations and not simply being a service provider. Someone like a GEO provider, for instance, isn't going to push hard to use SS other than as a potential cost opportunity over F9 in this case.

Last thing that immediately comes to mind, for years there's been talk of SX being a game changer in the industry due to their F9 prices and launch rates...but that's really not come good to any significant degree. Yeah entities have gravitated more toward SX and away from other launch providers, but if you look at total number of industry launch activity it's not like some huge step or knee in the curve due to SX. It's pretty fair to consider that logic will to some degree damp the SS "game changer" ambition. I know I'm broken record on this one, but the big problem here is that launch service portion of a space mission is already a pretty small fraction of the cost of the total space mission...so making a small number smaller, while great, isn't anywhere near a go/nogo.

So that all racks up to an implicit requirement that SS price be lower than F9 price for people to want F9, and IMO any chance of that happening requires near-full aspirational-level success of Starlink, because--as asserted above--that's really the only place SX is going to get the SS volume high enough to drive down the total recurring cost (RE+capex amortization).
 
First, while it would be inappropriate for me to talk actual numbers, I think it's fair to work this through public domain level info/speculation.

Second, I'd contest our disconnect is that I don't think you're asking the right question--few people are buying the enhanced F9's and even fewer who actually need it (Evidence: the super light SpaceForce! missions, the not-that-heavy Arabsat, etc), so using those enhanced variants maths' really doesn't address much market.

Near as makes no difference for an analogy, SS capacity is more or less that of a C5/AN-124. F9 capacity is more or less that of a 737 freighter. The aspiration for SS fully taking over SX launch duties comes down to an assumption of "build it and they will come"--that enough paying customers are going to want/use something WAY bigger than the 737 simply because its available. While certainly plausible, there's some major flaws in that logic. For instance: History has shown that for-profit companies are not going to spend more than they need to in their cost centers...so nobody's going to buy the Antonov when all they need is the 737. To that end, to date--and likely until SS becomes operational, its hard to imagine a material amount of top tier customers (= entities that are guaranteed to need launch services) will pivot their infrastructure toward something that needs a bigger-than-737

History has also shown that for-profit companies are reluctant to invest in their suppliers unless there's a really high probability of return, so those who could use SS the most (externally funded moonshot mega-constellations like AST) really have to play the game with respect to their investors--gotta get enough money to make it work but can't simply dump money into a supplier and hope-real-hard that it comes good...especially a supplier like SX who is obviously driven by internal aspirations and not simply being a service provider. Someone like a GEO provider, for instance, isn't going to push hard to use SS other than as a potential cost opportunity over F9 in this case.

Last thing that immediately comes to mind, for years there's been talk of SX being a game changer in the industry due to their F9 prices and launch rates...but that's really not come good to any significant degree. Yeah entities have gravitated more toward SX and away from other launch providers, but if you look at total number of industry launch activity it's not like some huge step or knee in the curve due to SX. It's pretty fair to consider that logic will to some degree damp the SS "game changer" ambition. I know I'm broken record on this one, but the big problem here is that launch service portion of a space mission is already a pretty small fraction of the cost of the total space mission...so making a small number smaller, while great, isn't anywhere near a go/nogo.

So that all racks up to an implicit requirement that SS price be lower than F9 price for people to want F9, and IMO any chance of that happening requires near-full aspirational-level success of Starlink, because--as asserted above--that's really the only place SX is going to get the SS volume high enough to drive down the total recurring cost (RE+capex amortization).

The point I've been addressing is the claim that a SS mission costs more than a Falcon one.
The issue is that SS is WAAAY too big for anything but the mega-ist of constellations or big lift human based missions (which is its point) and so there's not going to be a huge external demand to buying a more expensive rocket even if it has more favorable mass-to-orbit economics.
Cost trumps capacity. If an option is cheaper, it doesn't matter if it's overkill.
Case in point: HLS, as ApogeeSpace put it "Starship is basically an aircraft carrier when you're looking for a fishing boat, but it's less than half the cost of the other fishing boat."

Yes, F9H was the extremely case, it was intended
to illustrate a clear cost savings with SS. Even if the payload didn't need that much capacity.

With a >$5 million F9 second stage expended every launch, is the amortized launch cost of SS going to be more than the amortized launch cost of F9?
F9 has hit 15 launches, that's $75+ million in second stages plus 15 recovery missions for fairings/ boosters. If SS can do 30 missions (conservative), the comparison could be 2 F9 boosters, 28 recoveries, and $150 million in second stages.

From a SpaceX accounting perspective, Starlink is a no-op unless it's spun off. Until then, commercial missions offset Starlink/ SpaceX costs, not the other way around. In that vein, they could use a different dispenser and put commercial payloads up at a discount to F9 pricing.

I'd say F9 is a game changer, it just looks less so because SpaceX is the one changing the game. Could Starlink happen without F9? (Or Iridium gen 2?).
 
  • Like
Reactions: Grendal
If an option is cheaper, it doesn't matter if it's overkill.

Yes, that's my point. If overkill capacity is more expensive on the bottom line regardless if it's more cost efficient by mass, a customer is going to choose the less expensive solution.

Physics heavily drives most customer needs away from massive SS capacity, so there's not actually a first order incentive to want to buy the excess capacity [over F9], so SX really is going to have to get the internal cost of a SS launch really close to if not below falcon. ...and history has also shown that SX's/Elonco's aspirational internal costs are just that. Wasn't Elon talking about Falcon being $4M or something internal cost a few years ago?

I'd say F9 is a game changer, it just looks less so because SpaceX is the one changing the game. Could Starlink happen without F9? (Or Iridium gen 2?).

I think we're talking past each other again. F9 has saved a lot of companies real money on launch cost for sure, the point is that F9/SX hasn't been the catalyst for some game changing industry revolution as was wildly speculated by the fanbase. There's really no evidence that SS is going to be the catalyst for some industry revolution, or at least certainly not anytime soon. 2035? Maybe.

Iridium Next would have fine on another launcher. It would have been maybe a couple hundred million more on a $3-4B program. That's real money for sure, but there's no way a Chief Beancounter signs off on a multi-billion dollar program where saving (or not) ~10% of the cost is the literal make or break. That basically adds up to a quarter or two of Iridium revenue on a service that's based on 15 years satellites.

Starlink happening without F9 is a bit of a nuanced question because general consensus is that Starlink is pretty high up on the S-curve right now for the growth Falcon can support. Sure there's down-market regions that can open up to provide more revenue and the v2 minis will provide an incremental step in capacity, but by and large they're pretty tapped on capacity--more satellites (save for the polar shells) really won't move the needle much. To really scale from here they need V2 to step function, and V2 needs starship.
 
  • Like
Reactions: Grendal
Wasn't Elon talking about Falcon being $4M or something internal cost a few years ago?
Yes, when they were planning to reuse the second stage also, saving $5-$8 million a launch.

I think we're talking past each other again. F9 has saved a lot of companies real money on launch cost for sure, the point is that F9/SX hasn't been the catalyst for some game changing industry revolution as was wildly speculated by the fanbase. There's really no evidence that SS is going to be the catalyst for some industry revolution, or at least certainly not anytime soon. 2035? Maybe.

Starlink happening without F9 is a bit of a nuanced question because general consensus is that Starlink is pretty high up on the S-curve right now for the growth Falcon can support. Sure there's down-market regions that can open up to provide more revenue and the v2 minis will provide an incremental step in capacity, but by and large they're pretty tapped on capacity--more satellites (save for the polar shells) really won't move the needle much. To really scale from here they need V2 to step function, and V2 needs starship.
Yeah, seems to be some crossed wires. SpaceX has launched 73 Starlink missions. Would that have occured without a (mostly) reusable F9?
Agree further expansion relies on SS.

I'm not expecting industry to suddenly flock to SS nor the building a lot of huge satellites (though I do hope for some huge satellites to be built), only that I see SS being lower cost than F9. Especially since SpaceX will have them anyway for Starlink and marginal cost to fly a commercial payload would net them more than an F9. (Assuming multimode design and not Starlink only).
 
  • Like
Reactions: scaesare
Yes, when they were planning to reuse the second stage also, saving $5-$8 million a launch.




Yeah, seems to be some crossed wires. SpaceX has launched 73 Starlink missions. Would that have occured without a (mostly) reusable F9?
Agree further expansion relies on SS.

I'm not expecting industry to suddenly flock to SS nor the building a lot of huge satellites (though I do hope for some huge satellites to be built), only that I see SS being lower cost than F9. Especially since SpaceX will have them anyway for Starlink and marginal cost to fly a commercial payload would net them more than an F9. (Assuming multimode design and not Starlink only).
Do you think the JWST would have been made a lot simpler if they it flew in SS ? Some of the complex folding maneuvers needed to fit inside the Altas perhaps would have been simpler?
 
  • Like
Reactions: Ben W and mongo
Do you think the JWST would have been made a lot simpler if they it flew in SS ? Some of the complex folding maneuvers needed to fit inside the Altas perhaps would have been simpler?

Funny, I just posted something in a different thread related to telescopes.

Certainly one could design something like Webb to be launched in its flight-ish configuration, though one would expect significantly beefier structure to accommodate. There would still be micro adjustment motors on the individual elements too (and I assume hold downs for those elements during launch), and in general launch dynamics are a tricky thing for big structures, so it wouldn't simply be bolting the thing onto a SS and lighting the fuse.

On of the major restrictions on hucking something into space is that you don't want the natural frequency(ies) of the payload to overlap with those of the rocket's (which come largely from the big first stage engines), because they would come into resonance and basically shake the payload apart. To make sure this doesn't happen, the payload will always build itself stiff enough such that its first mode is safely higher than the rocket's first mode. The issue with building something stiff is that its not proportional to size--something small takes a little bit of mass to make stiff, something big takes way more than simply a linear amount of 'more mass' to make the same amount of stiff. Then of course, because you had to add a bunch of mass to beef it up you need to add a bunch more mass to make sure the beef mass is controlled...and so on and so on. It is very much a downward spiral of structural efficiency the larger the thing gets that you're trying to huck into space.

Its not total doom and gloom for SS though--unlike basically every other rocket in history that stacks a payload on top of a rocket and has it swinging around in the breeze like a flagpole on the top of a tall building (even STS, more or less) SS's non-deployable fairing enables structural coupling between a payload and the pretty-beef SS fuselage, beyond the traditional mechanical connection at the bottom of the payload. That's going to be a massive lever to pull when it comes to putting Big Payloads in space. Time will tell just how much coupling SX will allow, but it really is a if not the major differentiator. It's why V2's are using the pez. The sats are supported in a cage that's literally part of the fuselage, so each sat really only needs to support its own weight (as opposed to the weight of everything above it). There's not some massive stack/payload mass that needs to be a self supporting single body, but rather there's tens of much smaller masses (80 or whatever V2's, in this case) that simply need to be stiff enough that they don't flap into each other.