Artemis III and refuel in LEO

[sdsds]

I would prefer a metric involving rate, e.g. dollars per ton per week,  $/(t⋅wk). Less focus on a ton of cargo delivered; more on the rate at which tons of cargo are delivered.

[DanClemmensen]

I would prefer a metric involving rate, e.g. dollars per ton per week,  $/(t⋅wk). Less focus on a ton of cargo delivered; more on the rate at which tons of cargo are delivered.

In the context of the thread title, neither of these is valid. There is a specific mission and it has specific requirements, e.g.,  a certain amount of propellant available in a certain orbit at a certain date and time. The metric is the bid price to fulfill those requirements.

[Robotbeat]

But economies of scale are real. That's the reason container ships have grown ever larger even though the size of a container has not changed, or why supertankers grew to ridiculously large sized before finally running into physical limits. The measure for tanker rockets will be total cost/kg of delivered propellant.

Economies of scale are real, but they can take the form of physical dimensions or of quantity (or both).  Throughput is what matters in the end.  You can try to build the biggest, most capable HLV with the tech base you’ve got, but if it can only puts 70-130t into LEO once every year or two (cough...SLS...cough), you’re better off going with a less capable HLV that can put 60t to LEO 5+ times a year for 300t+ annually (cough...F9H actually did or will do this in 2023...cough).

Also, infrastructure, nature, and neighbors put limitations on physical size.  Yeah, there are some really big supertankers, but they can only visit certain ports.  If they’re honest, Airbus will tell you that the A380 was a mistake.  Australians can run several trailers behind their tractors, but you can’t do that on US roads.  Etc.

To be clear, I have no idea if Starship will prove too big or launch too infrequently or something else.  I’m just saying that in the abstract, big is not always better.  NASA human space flight has paid dearly by not heeding that advice and doing the analysis before going down blind alleys on STS size, Orion size, Ares V, and now SLS.

FWIW...

That's the reason I said "The measure for tanker rockets will be total cost/kg of delivered propellant." All of your points get rolled into total cost/kg. As of now, we are beginning to see limits on the number of launches per year from a site. This scarcity will begin to increase the cost of using a launch slot, in which case bigger is better, aside from any intrinsic economies of scale.

I'm not sure that we're near the limits of number of launches per year. The FAA and the range have drastically increased launch rate capacity, higher than they had even planned for this year. And SpaceX has not chosen to invest in more droneships or upper stage reuse, even though both would probably help increase launch rate... Because they believe Starship is the future and those other investments would either distract from Starship (opportunity cost) or they wouldn't have time to pay back given that they think Starship will be ready soon. Maybe we're seeing a limit to the *rate of increase* in launches per year.

[DanClemmensen]

But economies of scale are real. That's the reason container ships have grown ever larger even though the size of a container has not changed, or why supertankers grew to ridiculously large sized before finally running into physical limits. The measure for tanker rockets will be total cost/kg of delivered propellant.

Economies of scale are real, but they can take the form of physical dimensions or of quantity (or both).  Throughput is what matters in the end.  You can try to build the biggest, most capable HLV with the tech base you’ve got, but if it can only puts 70-130t into LEO once every year or two (cough...SLS...cough), you’re better off going with a less capable HLV that can put 60t to LEO 5+ times a year for 300t+ annually (cough...F9H actually did or will do this in 2023...cough).

Also, infrastructure, nature, and neighbors put limitations on physical size.  Yeah, there are some really big supertankers, but they can only visit certain ports.  If they’re honest, Airbus will tell you that the A380 was a mistake.  Australians can run several trailers behind their tractors, but you can’t do that on US roads.  Etc.

To be clear, I have no idea if Starship will prove too big or launch too infrequently or something else.  I’m just saying that in the abstract, big is not always better.  NASA human space flight has paid dearly by not heeding that advice and doing the analysis before going down blind alleys on STS size, Orion size, Ares V, and now SLS.

FWIW...

That's the reason I said "The measure for tanker rockets will be total cost/kg of delivered propellant." All of your points get rolled into total cost/kg. As of now, we are beginning to see limits on the number of launches per year from a site. This scarcity will begin to increase the cost of using a launch slot, in which case bigger is better, aside from any intrinsic economies of scale.

I'm not sure that we're near the limits of number of launches per year. The FAA and the range have drastically increased launch rate capacity, higher than they had even planned for this year. And SpaceX has not chosen to invest in more droneships or upper stage reuse, even though both would probably help increase launch rate... Because they believe Starship is the future and those other investments would either distract from Starship (opportunity cost) or they wouldn't have time to pay back given that they think Starship will be ready soon. Maybe we're seeing a limit to the *rate of increase* in launches per year.

Of course. SpaceX has chosen to go big. The counter-argument seems to be that lots of smaller LVs will be or would have been  more cost-effective. I don't see it. SpaceX also claims that Starship (specifically including its "stage 0") is designed for full and rapid reuse. They seem to have about a 5-year head start. They have designed for multiple launches per day from a single pad, which translates to at least 600 launches per year from each pad. I just don't see a path for a competitor to beat them in sending propellant to orbit, by any measure. Certainly not in the Artemis III context.

[TrevorMonty]

But economies of scale are real. That's the reason container ships have grown ever larger even though the size of a container has not changed, or why supertankers grew to ridiculously large sized before finally running into physical limits. The measure for tanker rockets will be total cost/kg of delivered propellant.

Economies of scale are real, but they can take the form of physical dimensions or of quantity (or both).  Throughput is what matters in the end.  You can try to build the biggest, most capable HLV with the tech base you’ve got, but if it can only puts 70-130t into LEO once every year or two (cough...SLS...cough), you’re better off going with a less capable HLV that can put 60t to LEO 5+ times a year for 300t+ annually (cough...F9H actually did or will do this in 2023...cough).

Also, infrastructure, nature, and neighbors put limitations on physical size.  Yeah, there are some really big supertankers, but they can only visit certain ports.  If they’re honest, Airbus will tell you that the A380 was a mistake.  Australians can run several trailers behind their tractors, but you can’t do that on US roads.  Etc.

To be clear, I have no idea if Starship will prove too big or launch too infrequently or something else.  I’m just saying that in the abstract, big is not always better.  NASA human space flight has paid dearly by not heeding that advice and doing the analysis before going down blind alleys on STS size, Orion size, Ares V, and now SLS.

FWIW...

That's the reason I said "The measure for tanker rockets will be total cost/kg of delivered propellant." All of your points get rolled into total cost/kg. As of now, we are beginning to see limits on the number of launches per year from a site. This scarcity will begin to increase the cost of using a launch slot, in which case bigger is better, aside from any intrinsic economies of scale.

I'm not sure that we're near the limits of number of launches per year. The FAA and the range have drastically increased launch rate capacity, higher than they had even planned for this year. And SpaceX has not chosen to invest in more droneships or upper stage reuse, even though both would probably help increase launch rate... Because they believe Starship is the future and those other investments would either distract from Starship (opportunity cost) or they wouldn't have time to pay back given that they think Starship will be ready soon. Maybe we're seeing a limit to the *rate of increase* in launches per year.

Of course. SpaceX has chosen to go big. The counter-argument seems to be that lots of smaller LVs will be or would have been  more cost-effective. I don't see it. SpaceX also claims that Starship (specifically including its "stage 0") is designed for full and rapid reuse. They seem to have about a 5-year head start. They have designed for multiple launches per day from a single pad, which translates to at least 600 launches per year from each pad. I just don't see a path for a competitor to beat them in sending propellant to orbit, by any measure. Certainly not in the Artemis III context.

Need someone to pay for missions that use all the propellant delivered to orbit. At this stage its just odd NASA manned lunar mission which requires use of SLS+Orion.

[DanClemmensen]

But economies of scale are real. That's the reason container ships have grown ever larger even though the size of a container has not changed, or why supertankers grew to ridiculously large sized before finally running into physical limits. The measure for tanker rockets will be total cost/kg of delivered propellant.

Economies of scale are real, but they can take the form of physical dimensions or of quantity (or both).  Throughput is what matters in the end.  You can try to build the biggest, most capable HLV with the tech base you’ve got, but if it can only puts 70-130t into LEO once every year or two (cough...SLS...cough), you’re better off going with a less capable HLV that can put 60t to LEO 5+ times a year for 300t+ annually (cough...F9H actually did or will do this in 2023...cough).

Also, infrastructure, nature, and neighbors put limitations on physical size.  Yeah, there are some really big supertankers, but they can only visit certain ports.  If they’re honest, Airbus will tell you that the A380 was a mistake.  Australians can run several trailers behind their tractors, but you can’t do that on US roads.  Etc.

To be clear, I have no idea if Starship will prove too big or launch too infrequently or something else.  I’m just saying that in the abstract, big is not always better.  NASA human space flight has paid dearly by not heeding that advice and doing the analysis before going down blind alleys on STS size, Orion size, Ares V, and now SLS.

FWIW...

That's the reason I said "The measure for tanker rockets will be total cost/kg of delivered propellant." All of your points get rolled into total cost/kg. As of now, we are beginning to see limits on the number of launches per year from a site. This scarcity will begin to increase the cost of using a launch slot, in which case bigger is better, aside from any intrinsic economies of scale.

I'm not sure that we're near the limits of number of launches per year. The FAA and the range have drastically increased launch rate capacity, higher than they had even planned for this year. And SpaceX has not chosen to invest in more droneships or upper stage reuse, even though both would probably help increase launch rate... Because they believe Starship is the future and those other investments would either distract from Starship (opportunity cost) or they wouldn't have time to pay back given that they think Starship will be ready soon. Maybe we're seeing a limit to the *rate of increase* in launches per year.

Of course. SpaceX has chosen to go big. The counter-argument seems to be that lots of smaller LVs will be or would have been  more cost-effective. I don't see it. SpaceX also claims that Starship (specifically including its "stage 0") is designed for full and rapid reuse. They seem to have about a 5-year head start. They have designed for multiple launches per day from a single pad, which translates to at least 600 launches per year from each pad. I just don't see a path for a competitor to beat them in sending propellant to orbit, by any measure. Certainly not in the Artemis III context.

Need someone to pay for missions that use all the propellant delivered to orbit. At this stage its just odd NASA manned lunar mission which requires use of SLS+Orion.

Nope, not "all the propellant". You only need someone to pay enough for the mission to be profitable. If your tanker can lift 20 tonne or 150 tonne, but the customer only needs 10 tonne, that's still OK if you charge enough.  You only get into trouble if the customer needs 20 tonne and you can only deliver 19 tonne in one launch.

Since we appear to be generalizing beyond Artemis III, there is also the possibility of long-term depot storage. Send up full loads to depot for whatever tanker you have and sell the customer whatever amount they want from depot. (There is the tiny little problem that the depot's orbit may not match the customer requirement...)

[litton4]

Isn't there is another downside of smaller launchers to assemble a "structure" is that you have to design and link the sections in space, which is still a labour intensive operation?

The US main structure part of ISS could have been assembled with a few (5?) Saturn V class launches. Instead of maybe 20 Shuttles (structure)  and lots of supporting flights to connect things up.

Then you end up with a more complex end product.

[Coastal Ron]

Isn't there is another downside of smaller launchers to assemble a "structure" is that you have to design and link the sections in space, which is still a labour intensive operation?

Assembling modules in space has not appeared to be very time consuming, or about an hour of time for modules that use the Common Berthing Mechanism (see the Post-launch section here on Wikipedia)

The US main structure part of ISS could have been assembled with a few (5?) Saturn V class launches. Instead of maybe 20 Shuttles (structure)  and lots of supporting flights to connect things up.

Instead of looking backwards to the Saturn V, which was out of production when the ISS was approved to be built, instead look at the alternatives we have today which include the Falcon 9 and larger launchers like New Glenn, Vulcan, and Starship. But of course NASA doesn't want to build ISS v2.0, so this really doesn't answer any important questions... 

Then you end up with a more complex end product.

If you ignore launch costs, then sure, maybe they should have used Saturn V rockets to launch much bigger ISS modules. And maybe NASA could use the SLS to launch up-sized modules, but both of those rockets were/are VERY expensive. The SLS costs $4B per launch, whereas you could launch Falcon 9 something like 50 times for the same cost as one SLS. So the overall cost would be less going with commodity launchers instead of the unique (and very costly) SLS.

And of course there are new launchers coming online soon that will have payload volumes larger than Falcon 9, so we don't lack the ability to build larger structures in space, we lack the MONEY.

So while the engineering viewpoint is always to maximize something, when you're talking about doing things in space we need to focus more on VALUE - how much we can do with the limited money we have.

[TheRadicalModerate]

And my question is how many Moon going Starship can be refueled by the filled Starship depot?

The Starship Depot is essentially a gas station.  It can refuel as many Lunar Starship missions as its service life allows.  (I don’t how many that is.)

If you’re asking how many Lunar Starships could be refueled at a Starship Depot before the depot needs refueling, it may be two.  Don’t quote this, but I’ve seen numbers bandied about that the Starship Depot will hold ~2500t of propellant.  The wet mass of a Starship at launch is ~1200t.  So if a Lunar Starship is also refueled with 1200t of propellant after reaching orbit, a full Starship Depot could do that twice before needing refueling itself.

…

So actually I don’t think the depot can do 2 lunar starship fills, at least not for a round trip.

If we look at the LEO-NHRO-Surface-NHRO-disposal delta-v, it’s actually about 9.6km/s. A filled out Starship (ie with 100tonnes of furnishings/cargo/etc) can do “only” 6.9km/s. Where does that 2.7km/s come from?
-lower cargo/furnishings for HLS than 100t
-slower transit (doesn’t help much since you have cryogen boiloff to keep in mind)
-reduced delta-v for disposal burn than the assumed 0.45km/s.

Even with all that, there’s still likely a 2-2.5km/s gap to make up.

So the solution is the refueling happens in a GTO-like orbit, not LEO. Alternatively, the Depot acts like a stage and boosts HLS to a GTO-like orbit.

With such a strategy, the 2500t of capacity is enough to refuel HLS *and* put it in a near-GTO-like elliptical orbit. But not to do so twice. (On the other hand, you could still do 2 LEO refuelings of one-way cargo HLSes.)

A few things:

1) The slide you have is for a non-BLT trip to lunar orbit.  BLT drops the delta-v for orbital insertion from 450m/s down to below 100m/s, and increases the TLI by 100-200m/s.  If you have good boiloff control (a BLT takes 60-120 days), there's some savings here.

Somewhere, there's a very similar slide with BLT options on it.  Too lazy to look for it right now, but its format is very similar to the one you attached, so I suspect it's from the same group.

2) Any portion of the conops containing humans is going to have increased flight performance reserves.  I can only guess what these are.  Two different levels of guesses:
a) I'd guess that non-crew segments required allowance for 2-3σ underperformance, while crewed segments would be at 3-4σ.
b) Since we don't know the performance distribution, I usually use 0.75% extra delta-v for non-crew segments, and 1.5% for crewed segments.  Note that by expressing these as percentages, they scale cleanly as other performance-affecting parameters vary.

3) You also have to include boil-off, sump losses, and ullage gas losses.  Boil-off is highly dependent on where the vehicle is parked.  Sump losses are anybody's guess--I've been using 1t of Starship, which is probably conservative.  I've been figuring ullage losses conservatively at 6bar for Starship, but a good case can be made for 3bar.  3bar saves somewhere between 2-4t, depending on how big you decide the lunar Starship tankage is.

4) Using these assumptions, an LSS dry mass of 95t, crew module of 15t, 2t up-mass and 1t down-mass ("up" and "down" being earth-relative), and Isp=369s average (assumes 50% throttle of one of the center RSLs), a single LEO refueling of a 1200t LSS doesn't even come close to being acceptable.  I've worked out the following use cases in this spreadsheet:

a) A 1200t Option A test article, assuming only 200m/s of delta-v after ascent, to make it as cheap as possible.  Launch-LEO-refuel-TLI BLT-NRHO-LS-ascentTest-crash.

b) A 1200t tankage LSS, single refueling in a low HEEO (the max HEEO reachable with no LEO refueling): Launch-HEEO-refuel-TLI BLT-NRHO-loiter-LS-NRHO. 

c) Two refuelings for a 1200t LSS, one in LEO and a second in a higher HEEO: Launch-LEO-refuel-HEEO-refuel-TLI BLT-NRHO-loiter-LS-NRHO.

d) A single refueling of an LSS with at least 1500t tankage: Launch-LEO-refuel-TLI BLT-NRHO-loiter-LS-NRHO.  I've been assuming that this has the same dry mass, since just rearranging the domes will still yield an LSS "garage" that's about 2m high, which should be fine for crew ops and small unpressurized payloads.

e) RB, you once argued that a 1200t LSS could refuel only in LEO if its dry mass was extremely low.  I modeled that:  dry+crew module would have to be 92t to work.  Not impossible, but unlikely, IMO.  Launch-LEO-refuel-NRHO-loiter-LS-NRHO.

f) Expendable Starships for HDL or CLPS missions, Launch-LEO-refuel-LS.  They're cheaper than reusing them.

g) An LSS used as an orbital transfer vehicle, with up to 4 crew brought up by an F9/D2, with the D2 capable of loitering uncrewed in LEO for up to 6 weeks.  This is an SLS/Orion replacement:  LEO-refuel-NRHO-LEOpropulsive.

h) When Starship becomes crew-certified for launch and EDL, it seems reasonable to look at an EDL-capable Starship (vanilla Starship with all the LSS features, re-engineered to support translunar reentry with 1500t tankage--call it 145t dry mass).  Launch (with crew)-LEO-refuel-TLI fast-LS-LLO-refuel-EDL.
 
i) It seems reasonable that SpaceX will based the LSS on the v2 Starship, which will have some stretch to the tanks, including outer mould line changes.  I haven't modeled this; I can't guess how the stretch plus mass savings will net out in terms of dry mass, so I didn't do this one.

j) All of these scenarios assume that all the necessary prop magically appears in the depot just before the LSS needs it.  In reality, it'll be accumulated over a period of at least weeks, more likely months, and we have no idea how much boiloff will occur during that accumulation period.  I've included a pretty-close-to-worst-case boiloff estimate for a 90-day campaign, which is then tweaked to come out to an integral number of tanker launches.  I can have almost 4t/day of boiloff and still do a mission that requires only 12 tankers.

6) I've posted this before, but it's relevant to this thread:  NASA did a trade study a few years back, which had extremely precise delta-v budgets for all phases of cislunar flight.  They took it down, but I squirreled away a copy here.  Here's a Google sheet with the same info.

Note that I'm assuming that these numbers do not include FPR.  If they do, then I'm being too conservative by quite a bit.

[TheRadicalModerate]

To close, there’s just a lot of unreality ignored reality in that video.  If a refuelable industry lander is too operationally complex, then where does the money come from to afford a non-refuelable one? 

In addition, it should be noted that the current Blue Origin / National Team architecture drank the entire giant tub of Kool-Aid wrt to refueling.  Its architecture is now essentially equivalent to SpaceX's, albeit with a set of much smaller vehicles.

[TheRadicalModerate]

And my question is how many Moon going Starship can be refueled by the filled Starship depot?

If you’re asking how many Lunar Starships could be refueled at a Starship Depot before the depot needs refueling, it may be two.  Don’t quote this, but I’ve seen numbers bandied about that the Starship Depot will hold ~2500t of propellant.  The wet mass of a Starship at launch is ~1200t.  So if a Lunar Starship is also refueled with 1200t of propellant after reaching orbit, a full Starship Depot could do that twice before needing refueling itself.

Is it possible that the starship don't need to be fully tanked for going to the Moon ?
Is double amount fuel sufficient for going to Mars ? They claim that Starship can reach Mars aand even beyond that.

Depends on the mission.  As it turns out, for the Option A (Artemis III) mission, an HLS Starship with only 1200t of tankage not only needs to be fully tanked, it needs to be fully tanked in a highly eccentric earth orbit with a considerably higher apogee than LEO.  Refueling in HEEO adds additional complexity.

I think the answer to this is that the HLS Starship will get more tankage, so it's able to take on about 1500t of prop.  Then it can do LEO-NRHO-LS-NRHO on one tank.

When the HLS Starship is reusable (this is the so-called Sustainable Lunar Transportation contract, and would likely first occur on Artemis VI), the missions go NRHO-refuel-LS-NRHO, and the Starship only needs about 520t of prop.  But that prop needs to be brought to NRHO from Earth, and that requires almost 1800t of prop to get it there and return the tanker back to Earth.

Note that it's actually cheaper, in terms of propellant that has to be brought to LEO, to send a new HLS Starship from LEO for each mission.  That essentially makes them expendable, but that might turn out to be more economical.  An extra couple of tankers almost certainly costs less than a new HLS Starship for every mission, but there are other considerations:

1) It's going to be a while before SpaceX can judge the longevity of an HLS Starship.  Will lunar dust degrade its performance and reliability?  How will its avionics and solar panels stand up to years in NRHO, with its more intense radiation environment?  What happens when its propellant tanks boil completely dry?  What kinds of consumables need to be resupplied?  All of these issue may require the HLS Starship to be overdesigned, which increases its cost.

2) The other major problem is that there's no way (currently) to reload the HLS Starship with large, unpressurized cargo for the next mission.  You can bring pressurized cargo up and transfer it through the Orion docking tunnel, but that constrains its dimensions and weight.  On the other hand, if the HLS Starship launches from Earth, it can carry large payloads like rovers, habs, etc., which can then be deployed by the crew.  That's a pretty big advantage.

[tbellman]

2) The other major problem is that there's no way (currently) to reload the HLS Starship with large, unpressurized cargo for the next mission.  You can bring pressurized cargo up and transfer it through the Orion docking tunnel, but that constrains its dimensions and weight.  On the other hand, if the HLS Starship launches from Earth, it can carry large payloads like rovers, habs, etc., which can then be deployed by the crew.  That's a pretty big advantage.

It is true there is no way to transfer large amounts of cargo, whether pressurized or unpressurized, to the HLS Starship once it is in space.  But that is not a problem, never mind a major problem.

For it to be a problem, there would need to a) exist any such large cargo, and b) be a benefit to bring said cargo on the HLS lander together with the crew.

On the contrary, sending large cargo on dedicated cargo landers is both the plan, and the better solution.  If NASA and partners ever manages to get the money to do so, that is.

Rovers, both pressurized like the expected JAXA rover, and unpressurized like the not-yet-awarded Lunar Terrain Vehicle, are better delivered before the crew arrives.  That way they can be tested without crew, and be used for reconnaissance, exploration, and/or other scientific examinations before crew arrival.  (And consistent with NASA trying to not buy a rover, but contracting rover-as-a-service, it will be the responsibility of the LTV provider to deliver their rover to the Moon.)

Habitat modules are unlikely to even fit in the "garage" of the HLS Starship and fit through the planned door (approximately 3m×3m), and are certainly not going to fit on the planned elevator.  A dedicated cargo ship can deliver much larger modules.  (Besides, there's currently no money in sight for separate habitats.)

Likewise any power systems: better to deliver and deploy them robotically before sending crew on the expensive and rare (once per year) SLS+Orion.

[TheRadicalModerate]

On the contrary, sending large cargo on dedicated cargo landers is both the plan, and the better solution.  If NASA and partners ever manages to get the money to do so, that is.

Rovers, both pressurized like the expected JAXA rover, and unpressurized like the not-yet-awarded Lunar Terrain Vehicle, are better delivered before the crew arrives.  That way they can be tested without crew, and be used for reconnaissance, exploration, and/or other scientific examinations before crew arrival.  (And consistent with NASA trying to not buy a rover, but contracting rover-as-a-service, it will be the responsibility of the LTV provider to deliver their rover to the Moon.)

Habitat modules are unlikely to even fit in the "garage" of the HLS Starship and fit through the planned door (approximately 3m×3m), and are certainly not going to fit on the planned elevator.  A dedicated cargo ship can deliver much larger modules.  (Besides, there's currently no money in sight for separate habitats.)

Likewise any power systems: better to deliver and deploy them robotically before sending crew on the expensive and rare (once per year) SLS+Orion.

Fair point that very large systems aren't going to fit in the garage, and that dedicated HDL or CLPS missions are the way to go there.  But there's almost certainly a wide array of equipment that's too big to go through an IDSS docking ring and safely stow in microgravity, but small enough to be stowed in the garage, using payload processing best practices, and deployed via the elevator.  That class of stuff could probably be batched together and transported with one large-ish HDL mission, but it'll likely be cheaper to co-manifest it with a crewed mission.

(BTW: We haven't seen what an automated deployment of a large module off of a cargo LSS would look like.  I suspect they'll blow the nose and fairing off early in the flight, then land with the payload exposed.  That still leaves the question of how you get a payload that's 30m above the ground deployed:  Internal crane with counterweight or counter-cantilever?  Ramp?  Super-gigando elevator, also with counterweight?  External crane?)

And I still think it's a while before NASA and SpaceX agree on the lifecycle of an SLT-class LSS.  A crewed LSS is obviously going to a lot more expensive in terms of quality control than an HDL/CLPS version, but how much of that expense will be driven by making it reusable vs. expendable?

[tbellman]

Fair point that very large systems aren't going to fit in the garage, and that dedicated HDL or CLPS missions are the way to go there.  But there's almost certainly a wide array of equipment that's too big to go through an IDSS docking ring and safely stow in microgravity, but small enough to be stowed in the garage, using payload processing best practices, and deployed via the elevator.  That class of stuff could probably be batched together and transported with one large-ish HDL mission, but it'll likely be cheaper to co-manifest it with a crewed mission.

Do you have any concrete examples of such equipment?  (And remember that it needs to be equipment that NASA would like to use within the Artemis program, and can potentially afford.)

(BTW: We haven't seen what an automated deployment of a large module off of a cargo LSS would look like.  I suspect they'll blow the nose and fairing off early in the flight, then land with the payload exposed.  That still leaves the question of how you get a payload that's 30m above the ground deployed:  Internal crane with counterweight or counter-cantilever?  Ramp?  Super-gigando elevator, also with counterweight?  External crane?)

On the last page of the Starship Users Guide there is a picture of Starship delivering two or possibly four Space Exploration Vehicles to the Moon, using an elevator.  (There exists a larger version of that picture, but I'm too lazy to find a copy right now.)  Granted, that is an early concept picture, and the SEV probably doesn't count as a large module in this context.

Beyond that, you probably have to think about how large and heavy individual modules will be.  A 30 tonne module should not be too difficult to hoist down using an internal crane.  And I think it will be quite some time until we are sending larger singular pieces of cargo to the Moon.

[Phil Stooke]

"Do you have any concrete examples of such equipment?  (And remember that it needs to be equipment that NASA would like to use within the Artemis program, and can potentially afford.)"

Not difficult to think of things like this once we get past the first few landings.  The build-up to Artemis Base Camp would require lots of infrastructure: solar power towers, habitat components, regolith-moving equipment, big rovers, ISRU plants, science equipment like telescopes or large drills.  That's just plucked out of my cranium with one of those Claw toys, so I'm sure more could be added.

[TheRadicalModerate]

Do you have any concrete examples of such equipment?  (And remember that it needs to be equipment that NASA would like to use within the Artemis program, and can potentially afford.)

Nothing specific, but I can think of all kinds of science experiments that would do poorly being manhandled through the docking tunnel, and might need a while to equilibrate from 1bar to a few nPa before the crew could calibrate and/or use them in the time allotted for the mission.  Also, stuff that has to survive the vibration and shock loads of a lunar landing is better integrated onto PAFs on the ground, rather than being stowed in a crew volume.

Think about stuff that was deployed unpressurized from an Apollo LM descent stage and you'll have the right scale.

On the last page of the Starship Users Guide there is a picture of Starship delivering two or possibly four Space Exploration Vehicles to the Moon, using an elevator.  (There exists a larger version of that picture, but I'm too lazy to find a copy right now.)  Granted, that is an early concept picture, and the SEV probably doesn't count as a large module in this context.

Yeah, I put about as much confidence in that picture as I put in the picture of the ITS sitting on a jovian icy moon.  That was back in the days of the stubby landing legs.

Don't get me wrong:  I think there are solutions.  I just don't know what they are.  It's a fairly important missing piece before you can start thinking about the dividing line between pressurized cargo, garage-deployed cargo, and HDL/CLPS-deployed cargo.

Beyond that, you probably have to think about how large and heavy individual modules will be.  A 30 tonne module should not be too difficult to hoist down using an internal crane.  And I think it will be quite some time until we are sending larger singular pieces of cargo to the Moon.

At the risk of drifting even further off-topic, my guess is that we won't see a piece of deployable cargo much bigger than 10t in the Artemis timeframe.  Anything bigger than that, the Starship is the cargo, with whatever you want built into the payload bay, never to be removed.  There may be deployable power and heat rejection, or maybe those are just hookups to a nascent base infrastructure.  But deploying massive equipment is going to take more than just a nascent base; it'll need a real one, with decent port facilities.

[Ciber]

For very large payloads, I Imagine you could manage something that involves an unpressurized cargo bay with large hatches on either end that allow crane segments to telescope out, with one side acting as a counterweight. Ideally, I think you use a container filled with smaller cargo as the counterweight, that way once the main payload is lowered you can unpack and lower individual smaller counterweight packages. Maybe a Starship variant with extra large landing legs for stability?

[JEF_300]

For whatever it's worth, I think we're being a bit too harsh on Destin (the guy in the video in the first post). Yes his points about the lander and the complexity of the mission are dubious, and rather backwards looking / Apollo-centric.

But his overall point is, "Hey, if this program is supposed to land humans on the Moon in 2 years, why is there still so much uncertainty?", and that's an extremely valid point which needs to be made more often.