Author Topic: Starship On-orbit refueling - Options and Discussion  (Read 812396 times)

Offline InterestedEngineer

  • Senior Member
  • *****
  • Posts: 2969
  • Seattle
  • Liked: 2254
  • Likes Given: 3705
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2940 on: 01/13/2025 05:33 pm »
___________
¹When I say "aerobrake" here, I mean a gentle set of braking maneuvers, with somewhere between 20m/s and 200m/s of delta-v removed per pass, rather than a single-pass aerocapture.  All such maneuvers require about 70m/s to raise the perigee at the end of the aerobraking, plus whatever maneuvering and attitude control is required between passes.  At 20m/s removed per pass, it takes 75 days to return to 300x300.  At 200m/s, it takes 5 days.

flaps + heatshield => ~20t.

70m/sec.  One engine firing at one G is about 600kg/sec for an empty Starship, so 70m/sec is 4.2t of propellant.

If you don't get your slow aerobrake down in less than 5 passes, you'd be better off doing a single pass aerocapture w/ heatshield.  Aka a standard Starship V3 and solve the coupling problems.

Offline Greg Hullender

  • Full Member
  • ****
  • Posts: 793
  • Seattle
    • Rocket Stack Rank
  • Liked: 583
  • Likes Given: 409
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2941 on: 01/14/2025 02:02 am »
As long as aerobraking is possible, it seems like a no-brainer over tanker shuttles with EDL.
No concerns about vehicles that can't be serviced? If a depot fails after fueling, it could waste the work of ten tanker trips, so it's not trivial.

Offline TheRadicalModerate

  • Senior Member
  • *****
  • Posts: 5131
  • Tampa, FL
  • Liked: 3755
  • Likes Given: 703
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2942 on: 01/14/2025 04:29 am »
___________
¹When I say "aerobrake" here, I mean a gentle set of braking maneuvers, with somewhere between 20m/s and 200m/s of delta-v removed per pass, rather than a single-pass aerocapture.  All such maneuvers require about 70m/s to raise the perigee at the end of the aerobraking, plus whatever maneuvering and attitude control is required between passes.  At 20m/s removed per pass, it takes 75 days to return to 300x300.  At 200m/s, it takes 5 days.

flaps + heatshield => ~20t.

70m/sec.  One engine firing at one G is about 600kg/sec for an empty Starship, so 70m/sec is 4.2t of propellant.

If you don't get your slow aerobrake down in less than 5 passes, you'd be better off doing a single pass aerocapture w/ heatshield.  Aka a standard Starship V3 and solve the coupling problems.

The only propulsive delta-v per pass is attitude control and a few m/s for course correction.  Then add 70m/s for circularization and 90m/s for NRHO-to-BLT insertion.

Returning propulsively from NRHO, even via a reverse BLT, is about 3340m/s.  But a tanker sitting in VLEO is useless unless you bring it back to EDL, which is another... 150m/s for landing delta-v?  3490m/s.

v3 tanker dry mass = ~160t @ Isp=369s, total prop consumption = 233t.

Let's use 150 passes @ 5m/s per aerobrake pass, plus about 90m/s for reverse BLT, and 70m/s for circularization:  910m/s.  Depot dry mass should be about 140t, same Isp, so prop consumption is 40t.

I could be wrong about course correction and attitude delta-v per pass, and long-term boiloff is an issue, but this is a depot; it should be pretty good at managing boiloff. Seems like a pretty definitive win.

And that's before you're factoring a second pair of RPODs for each campaign.

Offline TheRadicalModerate

  • Senior Member
  • *****
  • Posts: 5131
  • Tampa, FL
  • Liked: 3755
  • Likes Given: 703
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2943 on: 01/14/2025 04:31 am »
As long as aerobraking is possible, it seems like a no-brainer over tanker shuttles with EDL.
No concerns about vehicles that can't be serviced? If a depot fails after fueling, it could waste the work of ten tanker trips, so it's not trivial.

You can't service a depot no matter what.  So it sounds to me like making them do fewer RPODs per mission is what you want.

Online steveleach

  • Senior Member
  • *****
  • Posts: 2784
  • Liked: 3330
  • Likes Given: 1110
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2944 on: 01/14/2025 09:24 am »
Let's use 150 passes @ 5m/s per aerobrake pass, plus about 90m/s for reverse BLT, and 70m/s for circularization:  910m/s. 
How long would all those aerobraking passes take?

More to the point, what level of depot utilisation might that result in? Would you need 10 times as many depots? 50x? 100x?

Offline TheRadicalModerate

  • Senior Member
  • *****
  • Posts: 5131
  • Tampa, FL
  • Liked: 3755
  • Likes Given: 703
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2945 on: 01/14/2025 10:07 am »
Let's use 150 passes @ 5m/s per aerobrake pass, plus about 90m/s for reverse BLT, and 70m/s for circularization:  910m/s. 
How long would all those aerobraking passes take?

See attached.

Quote
More to the point, what level of depot utilisation might that result in? Would you need 10 times as many depots? 50x? 100x?
What level of depot utilization do you need?  The first two customers for depot are Artemis missions and somewhere between 1 and 5 Mars test missions.  Mars missions will refuel in VLEO only, so you're really only talking the Artemis missions.  POR is for less than 1/year, and if we get lucky that might treble (1/4mo), so one depot ought to handle everything.

I can't get real excited about massive scale-ups of refueling capacity.  There's unlikely to be a market for it until the 2030s, by which time they'll have changed almost everything operationally.

Online steveleach

  • Senior Member
  • *****
  • Posts: 2784
  • Liked: 3330
  • Likes Given: 1110
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2946 on: 01/14/2025 10:16 am »
If we're not talking about high-volume applications then don't even bother with a new (and disposable) depot variant, just use regular tankers.

Then once volumes are high enough for depots to not be disposable, utilisation will probably be something that needs to be considered.

Offline Greg Hullender

  • Full Member
  • ****
  • Posts: 793
  • Seattle
    • Rocket Stack Rank
  • Liked: 583
  • Likes Given: 409
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2947 on: 01/14/2025 01:56 pm »
If we're not talking about high-volume applications then don't even bother with a new (and disposable) depot variant, just use regular tankers.

Then once volumes are high enough for depots to not be disposable, utilisation will probably be something that needs to be considered.
Why do you think regular tankers will work? Even if you solve the QD/GSE gender problem, the boiloff from a tanker will be much higher than from a depot. Disposable or not, I think we're stuck with depots for the nonce.

I think a return time of 5 to 10 days is fine. If we wanted, say, monthly missions to Moon Base Alpha, we might need two depots.


Offline TheRadicalModerate

  • Senior Member
  • *****
  • Posts: 5131
  • Tampa, FL
  • Liked: 3755
  • Likes Given: 703
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2948 on: 01/14/2025 02:18 pm »
If we're not talking about high-volume applications then don't even bother with a new (and disposable) depot variant, just use regular tankers.

Then once volumes are high enough for depots to not be disposable, utilisation will probably be something that needs to be considered.
Why do you think regular tankers will work? Even if you solve the QD/GSE gender problem, the boiloff from a tanker will be much higher than from a depot. Disposable or not, I think we're stuck with depots for the nonce.

I think a return time of 5 to 10 days is fine. If we wanted, say, monthly missions to Moon Base Alpha, we might need two depots.

We're not talking about a disposable depot here.  It just fills up in VLEO from tankers, boosts up to the Final Tanking Orbit (FTO, in the FCC application's lingo), refuels the target Starship, then returns to VLEO for the next mission.  The only difference is that it takes longer to return via aerobraking.  If you need it sooner, most missions will allow propulsive return.  It'll just consume more prop.

Offline Greg Hullender

  • Full Member
  • ****
  • Posts: 793
  • Seattle
    • Rocket Stack Rank
  • Liked: 583
  • Likes Given: 409
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2949 on: 01/14/2025 02:43 pm »
We're not talking about a disposable depot here.  It just fills up in VLEO from tankers, boosts up to the Final Tanking Orbit (FTO, in the FCC application's lingo), refuels the target Starship, then returns to VLEO for the next mission.  The only difference is that it takes longer to return via aerobraking.  If you need it sooner, most missions will allow propulsive return.  It'll just consume more prop.
To be honest, though, I expect the depots will be disposable for quite a while. Their inability to EDL makes it hard for SpaceX to study them to see what parts are suffering wear and tear.

Another reason to want someone to build that orbital drydock. :-)

Online DanClemmensen

  • Senior Member
  • *****
  • Posts: 7457
  • Earth (currently)
  • Liked: 6061
  • Likes Given: 2535
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2950 on: 01/14/2025 02:54 pm »
We're not talking about a disposable depot here.  It just fills up in VLEO from tankers, boosts up to the Final Tanking Orbit (FTO, in the FCC application's lingo), refuels the target Starship, then returns to VLEO for the next mission.  The only difference is that it takes longer to return via aerobraking.  If you need it sooner, most missions will allow propulsive return.  It'll just consume more prop.
To be honest, though, I expect the depots will be disposable for quite a while. Their inability to EDL makes it hard for SpaceX to study them to see what parts are suffering wear and tear.

Another reason to want someone to build that orbital drydock. :-)
Yep. Same problem with HLS or indeed any non-EDL Starship that may have multiple missions. At least it's easy to replenish Depot, since it's whole function is to transfer fuel. HLS and other Ships will be harder to reprovision. NASA, et. al. have kept ISS up and more or less operational for 25 years, so it's at least conceivable that these Ships can be refurbished by a semi-permanent dry dock, but I suspect an EDL-capable repair ship makes more sense, since it can do the refurbishment in any LEO orbit.
« Last Edit: 01/14/2025 04:40 pm by DanClemmensen »

Online steveleach

  • Senior Member
  • *****
  • Posts: 2784
  • Liked: 3330
  • Likes Given: 1110
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2951 on: 01/14/2025 04:33 pm »
If we're not talking about high-volume applications then don't even bother with a new (and disposable) depot variant, just use regular tankers.

Then once volumes are high enough for depots to not be disposable, utilisation will probably be something that needs to be considered.
Why do you think regular tankers will work? Even if you solve the QD/GSE gender problem, the boiloff from a tanker will be much higher than from a depot. Disposable or not, I think we're stuck with depots for the nonce.

I think a return time of 5 to 10 days is fine. If we wanted, say, monthly missions to Moon Base Alpha, we might need two depots.

Just my reading of what SpaceX wrote in their FCC filing...

Quote from: FCC Technical Annex
Low Earth Orbit. SpaceX will conduct a range of Starship operations in low-Earth orbit (“LEO”). Each fully reusable Missions beyond LEO will also require a tanker version of Starship for propellant aggregation. During these missions, SpaceX will launch one or more propellant tanker versions of Starship. Some of these tanker variants will remain in LEO as “depots,” and will be filled with propellant by subsequent tanker launches. LEO operations will occur in a circular orbit at 281 km altitude (+/- 100 km) and an inclination ranging from equatorial (0 degrees) to polar.

Medium-Earth Orbit/High-Earth Orbit/Final Tanking Orbit. Missions beyond LEO will also require space station operations in medium-Earth orbit (“MEO”) to high-Earth orbit (“HEO”). For example, crewed lunar missions will include a secondary propellant transfer in MEO/HEO, the Final Tanking Orbit (“FTO”). Operations in MEO/HEO will occur in an elliptical orbit of 281km x 34,534 km and an altitude tolerance of +116,000/-24,000 km apogee and +/- 100 km perigee, with inclination between 28 and 33 degrees (+/- 2 degrees).
Tanker-to-tanker transfer isn't impossible, and neither is adding boil-off mitigation to tankers. This model would add a lot of flexibility to operations, which might be appealing to them before they've scaled up enough to justify dedicated depots.

Offline dglow

  • Senior Member
  • *****
  • Posts: 2381
  • Liked: 2688
  • Likes Given: 5177
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2952 on: 01/14/2025 04:47 pm »
We're not talking about a disposable depot here.  It just fills up in VLEO from tankers, boosts up to the Final Tanking Orbit (FTO, in the FCC application's lingo), refuels the target Starship, then returns to VLEO for the next mission.  The only difference is that it takes longer to return via aerobraking.  If you need it sooner, most missions will allow propulsive return.  It'll just consume more prop.
To be honest, though, I expect the depots will be disposable for quite a while.
Agree on the bias toward disposable depots.

Quote
Their inability to EDL makes it hard for SpaceX to study them to see what parts are suffering wear and tear.

Another reason to want someone to build that orbital drydock. :-)
If SpaceX needed to study depot-specific elements on the ground, the shorter walk would be adding EDL hardware to one and just bringing it back.

Offline InterestedEngineer

  • Senior Member
  • *****
  • Posts: 2969
  • Seattle
  • Liked: 2254
  • Likes Given: 3705
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2953 on: 01/14/2025 05:20 pm »
___________
¹When I say "aerobrake" here, I mean a gentle set of braking maneuvers, with somewhere between 20m/s and 200m/s of delta-v removed per pass, rather than a single-pass aerocapture.  All such maneuvers require about 70m/s to raise the perigee at the end of the aerobraking, plus whatever maneuvering and attitude control is required between passes.  At 20m/s removed per pass, it takes 75 days to return to 300x300.  At 200m/s, it takes 5 days.

flaps + heatshield => ~20t.

70m/sec.  One engine firing at one G is about 600kg/sec for an empty Starship, so 70m/sec is 4.2t of propellant.

If you don't get your slow aerobrake down in less than 5 passes, you'd be better off doing a single pass aerocapture w/ heatshield.  Aka a standard Starship V3 and solve the coupling problems.

The only propulsive delta-v per pass is attitude control and a few m/s for course correction.  Then add 70m/s for circularization and 90m/s for NRHO-to-BLT insertion.

Returning propulsively from NRHO, even via a reverse BLT, is about 3340m/s.  But a tanker sitting in VLEO is useless unless you bring it back to EDL, which is another... 150m/s for landing delta-v?  3490m/s.

v3 tanker dry mass = ~160t @ Isp=369s, total prop consumption = 233t.

Let's use 150 passes @ 5m/s per aerobrake pass, plus about 90m/s for reverse BLT, and 70m/s for circularization:  910m/s.  Depot dry mass should be about 140t, same Isp, so prop consumption is 40t.

I could be wrong about course correction and attitude delta-v per pass, and long-term boiloff is an issue, but this is a depot; it should be pretty good at managing boiloff. Seems like a pretty definitive win.

And that's before you're factoring a second pair of RPODs for each campaign.

I don't see the part about a one-pass aerobrake with a heatshield and circularize.  That's what I was proposing.  far less complicated conops, you are now in LEO and ready to act as a depot again for getting prop to higher energies.

I also don't get how you adjust the altitude of the 5m/sec aerobrake.  Each pass drops the altitude, accelerating the aerobrake, and eventually you run into thick enough atmosphere that without a heat shield you burn up (or rip off the solar panels, or  scar them with plasma etc). That requires some sort of deltaV at apogee to raise the the perigee which has to be done very every single pass.  668 passes, in the case of 5 m/sec. per pass.

668 passes through the van allen belts, into the very busy LEO to VLEO space is probably not the best idea from a logistics, scheduling, and traffic management standpoint.

Offline Twark_Main

  • Senior Member
  • *****
  • Posts: 4345
  • Technically we ALL live in space
  • Liked: 2328
  • Likes Given: 1369
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2954 on: 01/14/2025 05:35 pm »
I think a single shuttling depot is going to always beat out a shuttling tanker between two depots, as long as the depot can aerobrake¹ back into VLEO.  The aerobraking maneuver takes anywhere from a few days to a few months, depending on how aggressively you reduce delta-v per pass, but lunar missions are only going to happen every few months anyway.  Note the following:

1) Shuttling tankers (probably) have higher dry masses than shuttling depots.

2) Shuttling tankers lack whatever boiloff-reduction tech is on the depots.  This is especially important when the tanker needs to use a BLT to get to a lunar orbit, since transit will then take 2-3 months.

3) A tanker's direct EDL likely requires more delta-v for the landing burn than a depot's aerobraking campaign requires to manage attitude, course corrections to line up the next pass, and perigee raise at the end of the aerobraking.

4) Shuttling depots are completely standalone once they go to high orbit.  Their QD system will work directly with the target ship.  Shuttling tankers always need a depot on each end to get the QD gendering to work out, or they need the development of a completely new and androgynous QD for all Starships.

As long as aerobraking is possible, it seems like a no-brainer over tanker shuttles with EDL.

___________
¹When I say "aerobrake" here, I mean a gentle set of braking maneuvers, with somewhere between 20m/s and 200m/s of delta-v removed per pass, rather than a single-pass aerocapture.  All such maneuvers require about 70m/s to raise the perigee at the end of the aerobraking, plus whatever maneuvering and attitude control is required between passes.  At 20m/s removed per pass, it takes 75 days to return to 300x300.  At 200m/s, it takes 5 days.

In the context of a "shuttling tanker between two depots," yes I completely agree.

I know you know this, but note that what I was proposing is a quick tanker burn into HEEO, followed by (more or less immediately) dumping nearly the entire tanker into a departing Starship. The tanker can then re-enter on the next perigee.
« Last Edit: 01/14/2025 05:49 pm by Twark_Main »

Offline Twark_Main

  • Senior Member
  • *****
  • Posts: 4345
  • Technically we ALL live in space
  • Liked: 2328
  • Likes Given: 1369
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2955 on: 01/14/2025 05:44 pm »
We're not talking about a disposable depot here.  It just fills up in VLEO from tankers, boosts up to the Final Tanking Orbit (FTO, in the FCC application's lingo), refuels the target Starship, then returns to VLEO for the next mission.  The only difference is that it takes longer to return via aerobraking.  If you need it sooner, most missions will allow propulsive return.  It'll just consume more prop.
To be honest, though, I expect the depots will be disposable for quite a while. Their inability to EDL makes it hard for SpaceX to study them to see what parts are suffering wear and tear.

Another reason to want someone to build that orbital drydock. :-)

This is why I expect SpaceX is taking the dry mass hit and putting the active (and fragile) gear on the tankers to start. Once they get enough reflights for high reliability, they then can simply swap hardware to the more sensible arrangement which puts the gear on the depot.

Offline TheRadicalModerate

  • Senior Member
  • *****
  • Posts: 5131
  • Tampa, FL
  • Liked: 3755
  • Likes Given: 703
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2956 on: 01/14/2025 09:09 pm »
I don't see the part about a one-pass aerobrake with a heatshield and circularize.  That's what I was proposing.  far less complicated conops, you are now in LEO and ready to act as a depot again for getting prop to higher energies.

But one-pass requires TPS that's able to scrub off more than 3km/s of speed in a single pass--with the entry speed being 11km/s, instead of ~7.8km/s.  That's effectively an EDL-capable Starship.

If that kind of TPS has the properties needed to store prop in a low enough boiloff state, then a plain vanilla Starship probably does as well, and depots are superfluous.  But that doesn't sound like what's happening.

Quote
I also don't get how you adjust the altitude of the 5m/sec aerobrake.  Each pass drops the altitude, accelerating the aerobrake, and eventually you run into thick enough atmosphere that without a heat shield you burn up (or rip off the solar panels, or  scar them with plasma etc). That requires some sort of deltaV at apogee to raise the the perigee which has to be done very every single pass.  668 passes, in the case of 5 m/sec. per pass.

668 passes through the van allen belts, into the very busy LEO to VLEO space is probably not the best idea from a logistics, scheduling, and traffic management standpoint.

I wasn't proposing only 5m/s of orbital energy reduction per pass; I was proposing somewhere between 20m/s and 200m/s, conditions permitting.

However, there's some amount of apogee-based fiddling to ensure that the next pass hits the optimal entry angle and perigee.  Hopefully, that would be less than 5m/s, but that seems like a good arm-wave.

Note that there's nothing that requires the energy loss to be exactly the same value each time.  Indeed, it probably makes sense to increase the delta-v scrubbing as the perigee speed drops, since peak heating will be lower.  But the constant delta-v reduction is a nice simple model.  (I tried coming up with a model that was based on constant peak heating per pass, and failed miserably.  Hence the constant-loss model.  If you want to take a look, it's here.)

Offline InterestedEngineer

  • Senior Member
  • *****
  • Posts: 2969
  • Seattle
  • Liked: 2254
  • Likes Given: 3705
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2957 on: 01/14/2025 09:32 pm »
I don't see the part about a one-pass aerobrake with a heatshield and circularize.  That's what I was proposing.  far less complicated conops, you are now in LEO and ready to act as a depot again for getting prop to higher energies.

But one-pass requires TPS that's able to scrub off more than 3km/s of speed in a single pass--with the entry speed being 11km/s, instead of ~7.8km/s.  That's effectively an EDL-capable Starship.

If that kind of TPS has the properties needed to store prop in a low enough boiloff state, then a plain vanilla Starship probably does as well, and depots are superfluous.  But that doesn't sound like what's happening.

I never took that comment to mean solar tiles all around including the hot side.  Those'd be tiles on the aft side of the wind.

Also, they took samples.  It doesn't mean they doing it.  Just excited that they have a spaceX as a potential customer.

To me, a Depot is simply a Starship-3.  Keep it very simple, very few kinds of ships.

Offline InterestedEngineer

  • Senior Member
  • *****
  • Posts: 2969
  • Seattle
  • Liked: 2254
  • Likes Given: 3705
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2958 on: 01/14/2025 09:39 pm »


I wasn't proposing only 5m/s of orbital energy reduction per pass; I was proposing somewhere between 20m/s and 200m/s, conditions permitting.

However, there's some amount of apogee-based fiddling to ensure that the next pass hits the optimal entry angle and perigee.  Hopefully, that would be less than 5m/s, but that seems like a good arm-wave.

Note that there's nothing that requires the energy loss to be exactly the same value each time.  Indeed, it probably makes sense to increase the delta-v scrubbing as the perigee speed drops, since peak heating will be lower.  But the constant delta-v reduction is a nice simple model.  (I tried coming up with a model that was based on constant peak heating per pass, and failed miserably.  Hence the constant-loss model.  If you want to take a look, it's here.)
[/quote]

Oh sorry, I mistook the 5 m/sec as the braking applied not the apogee fiddling.

Let's suppose it's 50 m/sec per pass.  3200/50 = 64 passes.  64 * 5 = 320 m/sec.   All of that done with (oh dear here we go again) passive thrusters with an Isp of about 150.  About 84t of fuel if dry mass is 140.

84t is > 20t of heat shield + flaps.  I'm not sure this is a win.  It is very hard to beat one and done.

(I'm assuming circularization is going to be the same cost for both cases.  I may be wrong)

64 passes through the Van Allen belts + crowded orbitals is still 64 times the risk one is taking to aerobrake in one pass.

I am struggling with why a stock Starship-3 is not the ideal depot. Put heat shedding tiles on the backside (though I favor solar power + heat exchangers), face the idea side of the tiles towards the sun (or rotate them slowly), call it good.

Offline OTV Booster

  • Senior Member
  • *****
  • Posts: 5477
  • Terra is my nation; currently Kansas
  • Liked: 3778
  • Likes Given: 6565
Re: Starship On-orbit refueling - Options and Discussion
« Reply #2959 on: 01/15/2025 03:31 am »
We're not talking about a disposable depot here.  It just fills up in VLEO from tankers, boosts up to the Final Tanking Orbit (FTO, in the FCC application's lingo), refuels the target Starship, then returns to VLEO for the next mission.  The only difference is that it takes longer to return via aerobraking.  If you need it sooner, most missions will allow propulsive return.  It'll just consume more prop.
To be honest, though, I expect the depots will be disposable for quite a while. Their inability to EDL makes it hard for SpaceX to study them to see what parts are suffering wear and tear.

Another reason to want someone to build that orbital drydock. :-)
Yep. Same problem with HLS or indeed any non-EDL Starship that may have multiple missions. At least it's easy to replenish Depot, since it's whole function is to transfer fuel. HLS and other Ships will be harder to reprovision. NASA, et. al. have kept ISS up and more or less operational for 25 years, so it's at least conceivable that these Ships can be refurbished by a semi-permanent dry dock, but I suspect an EDL-capable repair ship makes more sense, since it can do the refurbishment in any LEO orbit.
LOL. We have gotten so used to SpaceX reusing boosters that we forget that, shuttle aside, not getting a ship back for inspection has been the norm.


And...  Wouldn't an orbital repair facility be called something other than a dry dock? Open the bay doors, run the ship in, seal it up and let in some air. It's an air dock.
We are on the cusp of revolutionary access to space. One hallmark of a revolution is that there is a disjuncture through which projections do not work. The thread must be picked up anew and the tapestry of history woven with a fresh pattern.

Tags: HLS 
 

Advertisement NovaTech
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0