What if Starship can't work as currently envisaged?

[RobLynn]

There is zero doubt in my mind that Reusable Starship will work spectacularly well, particularly given energy and iterative development work going into refinement of Raptor.  SpaceX has a great revenue stream now, so can afford to drive development of reusability to an extremely well developed end state.

That said I won't be surprised if it takes many years to get TPS reliable enough for multiple refights between necessary servicing, and I expect more re-design of aero-surfaces (and perhaps tank placement) towards that end - but they clearly have margin to add 10's of tonnes to TPS to buy them the desired reliability, and with AI robotics revolution occurring having an automated servicing step as part of refight to replace single or larger numbers of tiles in a few hours seems likely to be not very expensive anyway.

If turn-around refurbishment maintenance costs (engines or TPS) are higher than anticipated even after development then SpaceX has option of significantly increasing payload with drone-ship recovery, perhaps revisiting the optimal relative fuel loads of starship vs superheavy.

[Oersted]

Good thing SpaceX has Falcon 9 and Dragon. They can take their time to man-rate Starship.

[zubenelgenubi]

Moderator:
Personal attacks on this forum? No. ✋️

Also, no general politics.

Thread trimmed.

[Kaputnik]

My purpose in creating this thread wasn't to hand wring about whether Starship fails or not, or to declare my opinion about the matter, or SpaceX generally, or Musk specifically.

I wanted to discuss the options which are feasible to open up a bit of margin in the design in case that proves necessary.

If you don't wish to participate in a 'what if' scenario, you don't have to. If all you have to contribute is 'SpaceX will figure it out' then thanks but you're not really adding anything to the conversation.

So far suggestions have included:
- downrange booster recovery
- expendable ship
- just live with the smaller payload and fly more often
- downsized ship, LMO depots
- more specialised ships for different purposes
- more than two stages
- transpiration cooling

I know most of these would come with trade offs, and some aren't guaranteed to help, or even to work. But discussing why certain decisions are the right or wrong ones is pretty much why I'm on this forum. I can't be the only one.

[Apollo22]

Those who think Starship is now an "if" instead of "when", please specify your definition of it "works" so that your prediction can be refuted in the future.

What does it mean by Starship "works":
1. Full reuse - aka relaunch of a recovered ship - achieved?
2. Deployed Starlink operationally?
3. Orbital refueling demonstrated?
4. Starship landed on Moon/Mars?

Whataboutism.

[aporigine]

Those who think Starship is now an "if" instead of "when", please specify your definition of it "works" so that your prediction can be refuted in the future.

What does it mean by Starship "works":
1. Full reuse - aka relaunch of a recovered ship - achieved?
2. Deployed Starlink operationally?
3. Orbital refueling demonstrated?
4. Starship landed on Moon/Mars?

I’ll bite

1 through 3.
Upgrade 1 to rapid reuse ( <1week) with low turnaround workload.

4 would be nice, but 1 to 3 is the core capability if you ask me.

That said, to me Starship is probably (barring ugly engineering surprises) a when, not an if. It constitutes too large a positive move in being able to place mass into orbit (and with 3, beyond) to be abandoned without serious cause.

Iirc the last big project to try to make orbital access routine was VentureStar. It was hampered by at least three things:
- single stage to orbit, with constrained payload size and mass, even with very expensive old-space mass reduction measures
- exotic materials and manufacturing for the fuel tank
- unproven (at scale) TPS concept
(Aerospike engines and large lifting body were also new tech, but more likely to be realized within reasonable schedule and budget imo.)

Starship/Superheavy features none of these concerns, with TPS perhaps the biggest unknown. So, as long as nonengineering considerations do not rise to prominence, I am optimistic.

[meekGee]

I'm extremely confident that SpaceX can build an expendable Starship with a reusable SuperHeavy and deliver >100t of payload to LEO.  If SpaceX can really manufacture Raptors at their current scale for $1M apiece and SuperHeavy can get to 20x reuse, it's hard to imagine the cost of a launch being much more than $35M.  If we assume a 70% gross margin (roughly what F9 gets now), that would be ~$120M per flight.  That's a specific cost of $1200/kg, which is about a third of F9's, and half that of an FHE.

That's not a cost revolution, but it's better'n a sharp stick in the eye, and the superheavy lift, even with only partial reusability, is a revolution.

Two biggies that hurt if there's no Starship recovery (not necessarily reuse):

1) You can't land anything on Mars.
2) You can't get Starship crew-certified for EDL, which makes it uncertifiable for launch.


Specific cost is only half the story.  The other half is launch cadence.  Cadence can be limited by either the engine production rate, the hull production rate, or the turnaround rate; it's hard to tell which one is the critical path at this point.  But obviously reuse dramatically affects the needed production rates for a given cadence.

Refueling requires high cadence in addition to low specific cost.

You can certainly land on Mars with an ablative shield.

For reusable LEO, you could conceivably robotically replace a heat shield in a day.  If the shield is good for 2-3 LEO reentries, it's not perfect but it's an ok interim.

Also again, none of the last 4 failures had anything to do with fundamental challenges like heat shielding.

The question of "what if we can't make it work" is rooted in hysteria, not in engineering.  You could have equally asked it after the last successful water touchdown.

[thespacecow]

Those who think Starship is now an "if" instead of "when", please specify your definition of it "works" so that your prediction can be refuted in the future.

What does it mean by Starship "works":
1. Full reuse - aka relaunch of a recovered ship - achieved?
2. Deployed Starlink operationally?
3. Orbital refueling demonstrated?
4. Starship landed on Moon/Mars?

Whataboutism.

No it's not, if you start a thread with the title "What if Starship can't work as currently envisaged", asking for definition of "work as currently envisaged" is very much on topic.

[Twark_Main]

Funnily, I don't see the biggest risk for SpaceX not from the technical side, but from the political.

Either nationalizing SpaceX or driving out Musk (both openly discussed), would most likely stop any real development of Starship. Regardless of what you think about politics or the political believes of Musk, in a lawless America where the highest court regularly sides with the executive in an unprecedented way, the normal rules do not apply any more. Assuming that Trump will stay in power for the foreseeable future (which at least for me is a given), that bodes not well for SpaceX.

So my assumption is, that the Starship program will not get out of the prototype phase.

ps. I really hope, that I am wrong about that

I don't know if it's probably, but it's for sure a possibility.

The uncertainty and risk hanging over someone is the point of the intimidation.

Like others, I thought for years that Starship was a 'when', but after losing the last 4 ships and the political turmoil it's moved to a 'if' for me.

Those who think Starship is now an "if" instead of "when", please specify your definition of it "works" so that your prediction can be refuted in the future.

What does it mean by Starship "works":
1. Full reuse - aka relaunch of a recovered ship - achieved?
2. Deployed Starlink operationally?
3. Orbital refueling demonstrated?
4. Starship landed on Moon/Mars?

Whataboutism.

Asking wannamoonbase to clarify an ambiguous forward-looking statement is not an example of whataboutism.

[Twark_Main]

IMHO, go full in the Nova - Stoke solution...

Stoke is trying to combine an expander cycle engine with a regeneratively cooled heat shield, for a startup, I think their vision is more ambitious and unlikely than Spacex's starship.

"If you can't solve a problem, enlarge it." -- Dwight D. Eisenhower

Expanding the scope of your mental model to encompass adjacent systems can often allow you to see "silo-crossing" solutions that others miss.

When we look at Starship, all the pieces seem sensibly optimized on their own. There's a temptation to think there's nothing left that could be improved. But we shouldn't discount the possibility that a system-level reorganization (large or small) could find beneficial integration opportunities that achieve an even higher global optimum.

[Kaputnik]

Those who think Starship is now an "if" instead of "when", please specify your definition of it "works" so that your prediction can be refuted in the future.

What does it mean by Starship "works":
1. Full reuse - aka relaunch of a recovered ship - achieved?
2. Deployed Starlink operationally?
3. Orbital refueling demonstrated?
4. Starship landed on Moon/Mars?

My prediction remains that Starship as currently envisaged will succeed. I don't think it's certain, I don't have the level of confidence that I used to, but I'm definitely more in the 'when' than the 'if' camp.
Having said that, it is useful to define what we mean. So, I would answer yes to ask those questions, and further expand it to say that Starship will have worked as currently envisaged if it is a two stage vehicle with full, rapid reuse, capable of delivering over 100t to LEO at a cost that is significantly lower than any vehicle flying today.

[alugobi]

Is there any time-frame attribute to "envisaged"?

[Kaputnik]

Is there any time-frame attribute to "envisaged"?

Not by me, no. But there is to 'currently'.
Starship has already evolved significantly from the original MCT concept. I'm wondering how much it might evolve again to meet its goals, or whether we're at the optimisation phase.

[OTV Booster]

Funnily, I don't see the biggest risk for SpaceX not from the technical side, but from the political.

Either nationalizing SpaceX or driving out Musk (both openly discussed), would most likely stop any real development of Starship. Regardless of what you think about politics or the political believes of Musk, in a lawless America where the highest court regularly sides with the executive in an unprecedented way, the normal rules do not apply any more. Assuming that Trump will stay in power for the foreseeable future (which at least for me is a given), that bodes not well for SpaceX.

So my assumption is, that the Starship program will not get out of the prototype phase.

ps. I really hope, that I am wrong about that

I don't know if it's probably, but it's for sure a possibility.

The uncertainty and risk hanging over someone is the point of the intimidation.

Like others, I thought for years that Starship was a 'when', but after losing the last 4 ships and the political turmoil it's moved to a 'if' for me.

IMO loosing 4 ships comes under the heading of 'shit happens'. As suggested earlier it could be brain drain, Musk meister not paying attention, hubris with the new build, blind bad luck or some combination. It's a different root cause each time so there is hope.


Political, OTOH, is a whole different ball game. Add to that Musk crossing to the dark side and the ball game may get rained out. For the last three years I've felt that Elons erraticism could well be the single point of failure that dooms the program.


This is probably a rabbit hole we don't want to go down.

[steveleach]

Didn't Musk say something along the lines of "if you aren't frequently having to put stuff back, you weren't taking enough stuff away"?

Seems to me they might have just gone too far with v2, and are still figuring out which bits they need to add back.

[sdsds]

[...] I'm wondering how much it might evolve again to meet its goals, or whether we're at the optimisation phase.

They can't really start to optimize until they are flying some of the critical variant versions like tankers and depots and landers. The details of those variants will feed changes back into the base design. Some of that might be highly visible (taller boosters) or more subtle (improved tile manufacturing).

If I were going to pick a milestone out of ... nowhere ... I'd choose the point where tanker flight cadence is roughly where the F9 cadence is now. Maybe we could mostly all agree that would be a sign the system was a success? And that's still years away, right? Maybe multiple-digit years? It's hard to imagine a revamp of basic choices like methalox propellant and ring diameter. Personally I'm super-curious about whether they'll rethink the number of stages. Traditionally NASA (at least) have seen staging events as high risk. If instead they become super-reliable would it make sense to redistribute booster propellant into two stages?

[TheRadicalModerate]

Two biggies that hurt if there's no Starship recovery (not necessarily reuse):

1) You can't land anything on Mars.
2) You can't get Starship crew-certified for EDL, which makes it uncertifiable for launch.

You can certainly land on Mars with an ablative shield.

That's why "recovery" is somewhat separate from "reusability".  If you have an ablative sheild, then you can recover it, i.e., perform EDL on Earth or Mars--possibly no more than once.

For reusable LEO, you could conceivably robotically replace a heat shield in a day.  If the shield is good for 2-3 LEO reentries, it's not perfect but it's an ok interim.

It's better than nothing.  As long as specific cost and cadence make a particular market good enough to be enabled, that's good enough.

Also again, none of the last 4 failures had anything to do with fundamental challenges like heat shielding.

Yes, I agree that the heat shield is far from the only feature that's needed to enable a particular market.  But there is a finite set of things that, if not present, will disable the market.

The question of "what if we can't make it work" is rooted in hysteria, not in engineering.  You could have equally asked it after the last successful water touchdown.

Feel free not to participate.  That's the premise of the thread.

It would be useful to have a matrix of what markets need what features.  Then, if Starship can't provide that feature, you know what the addressable market is likely to be.

[meekGee]

Two biggies that hurt if there's no Starship recovery (not necessarily reuse):

1) You can't land anything on Mars.
2) You can't get Starship crew-certified for EDL, which makes it uncertifiable for launch.

You can certainly land on Mars with an ablative shield.

That's why "recovery" is somewhat separate from "reusability".  If you have an ablative sheild, then you can recover it, i.e., perform EDL on Earth or Mars--possibly no more than once.

For reusable LEO, you could conceivably robotically replace a heat shield in a day.  If the shield is good for 2-3 LEO reentries, it's not perfect but it's an ok interim.

It's better than nothing.  As long as specific cost and cadence make a particular market good enough to be enabled, that's good enough.

Also again, none of the last 4 failures had anything to do with fundamental challenges like heat shielding.

Yes, I agree that the heat shield is far from the only feature that's needed to enable a particular market.  But there is a finite set of things that, if not present, will disable the market.

The question of "what if we can't make it work" is rooted in hysteria, not in engineering.  You could have equally asked it after the last successful water touchdown.

Feel free not to participate.  That's the premise of the thread.

It would be useful to have a matrix of what markets need what features.  Then, if Starship can't provide that feature, you know what the addressable market is likely to be.

What features are at risk?

All markets need SH.

All markets need non-exploding COPVs and engines, fuel lines that don't shake apart, and I forget what #4 was.

At risk is a practical reusable heat shielding. Ablatives are good enough for Mars, and are a way out for LEO if done robotically and efficiently.

Refueling needs to be developed, but it's hardly a core challenge.

So - I don't see what data is pointing to a problem, other than the emotional spiral that happens after you lose 4 games in a row.

[TheRadicalModerate]

It would be useful to have a matrix of what markets need what features.  Then, if Starship can't provide that feature, you know what the addressable market is likely to be.

What features are at risk?

It's hard to get something that's clear enough.  Some examples:

1) If booster isn't reusable, I assume that nothing works, or only works for extreme specialty launches, like a robotic interplanetary probe.

2) Can you get a viable specific cost and launch cadence for Starlink v3 if Starship isn't reusable?  That's both a manufacturing and performance question.

3) What about 3rd-party megaconstellation launches? 

4) What about 3rd-party heavy launches, needing a jettisonable fairing or a chomper?

5) I mostly agree that refueling is tractable, but almost all BEO missions (as well as direct-to-GEO missions) can't occur without it.  And it is a completely new RPOD mechanism.

6) You can't crew-certify Starship for launch/EDL, or for martian EDL, without at least Starship recoverability.

There are a lot of moving parts here.  Performance estimates are all over the map.  Most of the cadence estimates require modeling how well manufacturing can substitute for lack of reusability, or how long turnaround is if they have to cut over to something like ablative if the Ship is to be made recoverable.

[Oli]

So, I would answer yes to ask those questions, and further expand it to say that Starship will have worked as currently envisaged if it is a two stage vehicle with full, rapid reuse, capable of delivering over 100t to LEO at a cost that is significantly lower than any vehicle flying today.

SpaceX can make it work if they have the payloads. It was Starlink that made reusable Falcon 9 successful. I'm not yet convinced Starlink can do the same for Starship.