What if Starship can't work as currently envisaged?

[meekGee]

First off, don't accuse people of "copium" on these forums. There is no "coping" going on here. That's effectively a personal attack saying "this person is a fan boy and is only saying what they're saying because their brainwashed". Don't do that.

Secondly, it's not damage control if it's true. The booster was not the pacing item for the next flight. Yes there is likely some schedule shift from the booster loss, but not as much as if it was the pacing item.

Thirdly, Flight 12 was not supposed to take place in December or in January. There was no such published date.

Hey I got some "copium flak" too, but it's ok.  I have thick skin, and those types of posts reflect badly mostly on the posters.  Bad form, and hardly convincing anyone except those already convinced.

Good other points, though it's a precise repeat of every time something went a little bit wrong.

There's a party of "haha your thing exploded it'll take years, decades even, to recover" and a week later it turns out the planet in fact continued to revolve.

Again, more than anything else, those types of posts reflect badly on the posters.

If there's valid criticism, it should apply when the program goes to plan, not when there was a bad week. Every program has bad weeks.

The criticism I level at BO is actually in the best case.  What's missing in the case that everything does go to plan (as it did last week).

I don't see a lot of criticism of what happens if Starship works as intended - all I see is posts that stainless is doomed because a COPV blew up, or that Starlink is a money loser but wait Kuiper will take over soon.

[RJMAZ]

But let's say it can't be made to work. Full and rapid reuse eats all the payload. Or the vehicle can't be made robust enough for economic reuse and acceptable reliability.

What would you change about the design in order to arrive at a vehicle which comes closest to achieving the program goals?

I suggested this over a year ago and received a lot of negative feedback.

My proposal was for a three stage Starship where only the third stage is disposable. By going to three stages reduces the mass of the third stage that is disposed of. Like Falcon Heavy the first stage returns to the launch site but the second stage lands on a ship.

Here is a link to my thread

https://forum.nasaspaceflight.com/index.php?topic=61709.0

My thread also mentioned using these disposable upper stages and linking them in orbit into a ring to form a giant space station. My disposable upper stage would have having conventional payload fairings. The upper dome, common dome and engine sections could have bolted sections so once 50+ upper stages are bolted into a ring you could walk around the full ring. The ring spins to create gravity.  They can then stack the rings to form a spinning tube.

I also mentioned the disposable upper stages could be great one way cargo/tankers to mars. Only a small frsction of the Starships need to reusable or have a heatshield.

[spacenut]

The ships are able to land even under extreme duress.  Even if they need to re-tile them every time, it's already good enough.

There is little doubt that there's plenty of extra mass hiding in the crude solutions implemented so far, and with the upcoming stretch, it'll be enough - as long as they can launch multiple times a day.

On that narrow front, I think people are breathing easier these days.

If they need to tile the ships every single time, then I consider the whole Starship program a failure.

And what do you mean by multiple launches per day? Launches of a booster? From a pad? Across  all their pads? Because none of these are likely this decade.

They are building 5 launch pads with SpaceX already talking about needing more.  With enough boosters and Starships, they could launch multiple launches a day.  They also have a large megabay being built in Florida, with 3 pads under construction.  They have 2 at Starbase.  They will probably build one at Vandenberg for polar Starlink orbits.  Multiple launches could be 1 per day from any of the three locations.  That is 3 per day.  Fuel depots have to be filled for lunar and Mars trips.  Starlink version 3's have to be launched via Starships.  They also mentioned phasing out F9 and FH to only use Starships.  So multiple launches can be made this decade. 

As mentioned the booster is basically ready.  Starships have returned and landed in the ocean, so they only has to land back at the launch pads.  They are very close to working.  I predict they will go with transpiration cooling at the hottest points to keep from wearing down the tiles. 

As a side note, I like what Stoke Space is doing with a capsule shaped upper stage for reuse.  Kind of wish SpaceX had gone with something like that.  Philip Bono suggested this in the 1960's. 

[RJMAZ]

As mentioned the booster is basically ready.  Starships have returned and landed in the ocean, so they only has to land back at the launch pads.  They are very close to working.  I predict they will go with transpiration cooling at the hottest points to keep from wearing down the tiles. 

No one is doubting Starship will work and will successful land. The only doubt is the level of refurbishment required for the next flight. I doubt Starship will ever be refuelled and reflown the same day.

I'm expecting a week long inspection and refurbishment process at the minimum so they will need to have a large fleet and cycle them through the refurbishment center. There will always be a cost of refurbishment. How it compares to a disposable stage is still unknown.

A disposable upper stage will be much lighter and cheaper. Removing sea level landing engines, heatshield or fins, using a normal payload fairings and not requiring fuel for landing would easily see a 50% increase on payload to orbit. The disposable stage might be less than half the cost.

The calculations then have to be made.
3 reusable flights versus 2 disposable flights to get the same payload mass to orbit. An extra launch plus 3 upper stage refurbishments need to be cheaper than two disposable upper stages. This is the challenge. I think it will take more than 10 years until the refurbishment and extra launch becomes cheaper.

I don't think reusing the upper stages will end up being massively cheaper than disposable upper stages. I can't see the engines doing 100 flights without regular refurbishment. Space travel will still be very expensive.

[Legios]

3 reusable flights versus 2 disposable flights to get the same payload mass to orbit. An extra launch plus 3 upper stage refurbishments need to be cheaper than two disposable upper stages. This is the challenge. I think it will take more than 10 years until the refurbishment and extra launch becomes cheaper.

Where have I heard this line of thinking before?

[spacenut]

I don't think refurbishing metholox engines will be a problem.  No coking.  They should last longer than the Merlin kerolox engines.  The TPS will be more of a problem in reuse.  Can't be burning up fins. 

[steveleach]

Has the need for an occasional refurb become the definition of "can't work as currently envisaged" now?

Feels like this thread may have run its course.

[redneck]

But let's say it can't be made to work. Full and rapid reuse eats all the payload. Or the vehicle can't be made robust enough for economic reuse and acceptable reliability.

What would you change about the design in order to arrive at a vehicle which comes closest to achieving the program goals?

I suggested this over a year ago and received a lot of negative feedback.

My proposal was for a three stage Starship where only the third stage is disposable. By going to three stages reduces the mass of the third stage that is disposed of. Like Falcon Heavy the first stage returns to the launch site but the second stage lands on a ship.

Here is a link to my thread

https://forum.nasaspaceflight.com/index.php?topic=61709.0

My thread also mentioned using these disposable upper stages and linking them in orbit into a ring to form a giant space station. My disposable upper stage would have having conventional payload fairings. The upper dome, common dome and engine sections could have bolted sections so once 50+ upper stages are bolted into a ring you could walk around the full ring. The ring spins to create gravity.  They can then stack the rings to form a spinning tube.

I also mentioned the disposable upper stages could be great one way cargo/tankers to mars. Only a small frsction of the Starships need to reusable or have a heatshield.

I went back and reread your thread. You start off with a reasonable question of "what if the Starship is not economically viable?". Then wander off into many questionable or invalid assumptions. Including no ISRU on Mars until hundreds of landings and aerobraking above LEO velocities not possible. A reasonable question and discussion does not involve creating various epicycles to make it close.

I also have some skepticism that Starship will be as economically viable as projected. I do have some interest in variations. I am not going to spend much effort on thinking about those variations until Starship is proven to be less successful than many expect. Final stage being one raptor and expendable can make sense under some assumptions. Those assumptions require considerable thought on the middle stage recovery and reuse that does not lend itself to superficial discussion on this forum. Also that the various three stage concepts are no longer Starship

[sstli2]

Has the need for an occasional refurb become the definition of "can't work as currently envisaged" now?

Feels like this thread may have run its course.

As the vision is and has always been "full and rapid re-use", any limitations to either of those parameters does undermine that vision.

Nothing has changed since the start of conversation. We've known for well over a year now that Starship can make it back in one piece. The question is and has always been how much refurbishment will be required and ultimately how operable full reusability will be.

[Twark_Main]

Has the need for an occasional refurb become the definition of "can't work as currently envisaged" now?

Feels like this thread may have run its course.

As the vision is and has always been "full and rapid re-use", any limitations to either of those parameters does undermine that vision.

The full quote is "full and rapid reuse, like an airplane."

Airplanes definitely do require periodic maintenance. They don't need to be opened up after every flight, however, so this is massive progress over all previous reusable rockets.

https://www.naa.edu/types-of-aviation-maintenance-checks/

Nothing has changed since the start of conversation. We've known for well over a year now that Starship can make it back in one piece.

This one is easy to debunk. First post in the thread:

But let's say it can't be made to work. Full and rapid reuse eats all the payload. Or the vehicle can't be made robust enough for economic reuse and acceptable reliability.

So there were indeed questions about it coming back in one piece.

[sstli2]

Airplanes definitely do require periodic maintenance. They don't need to be opened up after every flight, however, so this is massive progress over all previous reusable rockets.

https://www.naa.edu/types-of-aviation-maintenance-checks/

The question will be "how full", and "how rapid". I cannot say whether RJMAZ's assertion of a "week long" refurbishment timeline will be accurate, however Falcon 9 boosters have already been turned around in as few as 9 days, and most would say that falls short of "rapid".

But let's say it can't be made to work. Full and rapid reuse eats all the payload. Or the vehicle can't be made robust enough for economic reuse and acceptable reliability.

So there were indeed questions about it coming back in one piece.

Nope. There is nothing in that quote that says anything about whether it comes back in one piece. The question is valid; for instance, can spot-refurbishment of the heat shield produce a reliable heat shield for subsequent flights, or will larger-scale refurbishment be required for sufficient reliability. That question remains to be answered empirically.

As you are "debunking" a straw man, let me restate my prior post, so it cannot be misinterpreted. Generally most people thought a Starship could be brought back through re-rentry and landed. That was never the real debate. The question was always as to what state that ship would be in and how operable and cost-effective reusability would be given that state.

[steveleach]

The question will be "how full", and "how rapid".

Those answers are always going to be subjective, so on that basis you could still argue that Starship doesn't "work as currently envisaged" even if it is launching daily, ships are landing people on Mars and returning them to Earth.

To be honest, I see no reason why this debate about Starship reusability won't end up like the F9 reusability one, with people now saying it is only viable because of Starlink (which wasn't a thing when they made their prediction).

[sstli2]

you could still argue that Starship doesn't "work as currently envisaged" even if it is launching daily

If Starship ended up like Falcon 9 and launched daily with expendable upper stages, then that would be a good point. If Starship launched daily with a fleet of 30 ships each requiring 30 days of refurbishment, that would still be a relevant point, but less so if the economics still work. So to answer the title question - "What if Starship can't work as currently envisaged" - in the former case it would be a failure. In the latter case it would likely be at least somewhat successful.

now saying it is only viable because of Starlink

A high launch cadence does improve the economics of reusability and can move it from impractical to practical.

We're all adults here. We can debate and reason about this. There is no basis to assume disingenuity on behalf of those who apply scrutiny to the overall economics, unless you seek an echo chamber.

[steveleach]

now saying it is only viable because of Starlink

A high launch cadence does improve the economics of reusability and can move it from impractical to practical.

We're all adults here. We can debate and reason about this. There is no basis to assume disingenuity on behalf of those who apply scrutiny to the overall economics, unless you seek an echo chamber.

Agreed, but there's a big difference between discussing the viability of an idea and post-hoc rationalisation of an incorrect prediction.

This thread, like others before it, is descending into meaningless debate about the precise meaning of particular phrases in particular posts.

[Exastro]

This thread, like others before it, is descending into meaningless debate about the precise meaning of particular phrases in particular posts.

I think the root cause may be the ambiguous thread title.  It'd be better if it were more specific about what "can't work as currently envisaged" means:  Performance shortfall, uneconomic reusability, Proton-level reliability, inability to ramp the cadence, inability to stay viable for long duration missions, inability to safely reenter at interplanetary speeds, or something else? 

Starship is meant to do so many things well, which makes the space spanned by "can't work" many-dimensional.

[Twark_Main]

Airplanes definitely do require periodic maintenance. They don't need to be opened up after every flight, however, so this is massive progress over all previous reusable rockets.

https://www.naa.edu/types-of-aviation-maintenance-checks/

The question will be "how full", and "how rapid". I cannot say whether RJMAZ's assertion of a "week long" refurbishment timeline will be accurate, however Falcon 9 boosters have already been turned around in as few as 9 days, and most would say that falls short of "rapid".

One hour turnaround is what Elon Musk is aiming for. Again, similar to an airplane.

But let's say it can't be made to work. Full and rapid reuse eats all the payload. Or the vehicle can't be made robust enough for economic reuse and acceptable reliability.

So there were indeed questions about it coming back in one piece.

Nope. There is nothing in that quote that says anything about whether it comes back in one piece.

Percent chance of RUD is part of "reliable," obviously. 

["Skip a bit, Brother..."]

Generally most people thought a Starship could be brought back through re-rentry and landed. That was never the real debate.

The historical revisionism is complete, lol.


And now, at long last, your point:

The question the what state the ship is in and how operable and cost-effective reusability is given that state.

Sure, you got me there!  How good it is depends on how good it is.  I guess I can't argue with that.