Author Topic: NASA's Artemis Program Updates and Discussion Thread 5  (Read 837229 times)

Offline Zed_Noir

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #180 on: 03/14/2023 11:09 am »
<snip>
Of course, SpaceX could decide on its own to do a crewed Option B LSS test in between Artemis III and IV, cobbled together out of an F9/D2 to do crew launch and EDL, an LSS to do LEO-NRHO-LEO, and the Option B LSS to do NRHO-LS-NRHO.  But I doubt Congress would let NASA fund the mission.  It's not a cheap mission, and would require the LSS to have active/passive docking.
Will point out that eventually SpaceX needs the dual active and passive docking capabilities for their vehicles.

If the Artemis program stumbles for too long and the LSS landers along with the supporting tankers are ready. SpaceX might consider mounting a private Option B LSS crewed landing test mission. Of course this would be the second LSS landing on the Moon after the uncrewed LSS test landing around the end of 2024.

While such a Lunar test mission might be expensive. It will be much cheaper doing a LEO-LS-LEO mission profile, skipping the NRHO part along with not using the SLS and the Orion.

Probability for such a mission is very minimal but not zero.


Online DanClemmensen

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #181 on: 03/14/2023 01:55 pm »

Of course, SpaceX could decide on its own to do a crewed Option B LSS test in between Artemis III and IV, cobbled together out of an F9/D2 to do crew launch and EDL, an LSS to do LEO-NRHO-LEO, and the Option B LSS to do NRHO-LS-NRHO.  But I doubt Congress would let NASA fund the mission.  It's not a cheap mission, and would require the LSS to have active/passive docking.
Since Orion has an active-only IDSS, the Option A HLS must have passive IDSS capability. Since Gateway has passive IDSS, Option B HLS must have active IDSS capability. Crew Dragon has active-only IDSS.  This all means you can use an Option A HLS for the LEO-NRHO-LEO keg of the trip and everything will just work.

However, the only real reason to implement active-only IDSS is to save mass, and it's not much mass. So just go ahead and add the passive hooks to convert the active-only IDSS to an active/passive IDSS.

The other potential problem is the geometry. If the HLS IDSS is in the nose, then no problem. If it is in the waist near the airlocks, then the geometry for HLS-to-HLS docking might get interesting.

Offline TheRadicalModerate

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #182 on: 03/14/2023 04:51 pm »
Will point out that eventually SpaceX needs the dual active and passive docking capabilities for their vehicles.

If the Artemis program stumbles for too long and the LSS landers along with the supporting tankers are ready. SpaceX might consider mounting a private Option B LSS crewed landing test mission. Of course this would be the second LSS landing on the Moon after the uncrewed LSS test landing around the end of 2024.

While such a Lunar test mission might be expensive. It will be much cheaper doing a LEO-LS-LEO mission profile, skipping the NRHO part along with not using the SLS and the Orion.

You can't do LEO-LS-LEO without refueling somewhere in cislunar space.  If you do that pre-descent, it's really expensive and complex.  If you do it post-ascent, you run the risk of stranding the crew if the refueling fails.  I think that risk rapidly diminishes with refueling experience, but it's not the sort of thing you want to do on your second lunar mission without a Plan B.

Offline TheRadicalModerate

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #183 on: 03/14/2023 04:57 pm »

Of course, SpaceX could decide on its own to do a crewed Option B LSS test in between Artemis III and IV, cobbled together out of an F9/D2 to do crew launch and EDL, an LSS to do LEO-NRHO-LEO, and the Option B LSS to do NRHO-LS-NRHO.  But I doubt Congress would let NASA fund the mission.  It's not a cheap mission, and would require the LSS to have active/passive docking.
Since Orion has an active-only IDSS, the Option A HLS must have passive IDSS capability. Since Gateway has passive IDSS, Option B HLS must have active IDSS capability. Crew Dragon has active-only IDSS.  This all means you can use an Option A HLS for the LEO-NRHO-LEO keg of the trip and everything will just work.

However, the only real reason to implement active-only IDSS is to save mass, and it's not much mass. So just go ahead and add the passive hooks to convert the active-only IDSS to an active/passive IDSS.

The other potential problem is the geometry. If the HLS IDSS is in the nose, then no problem. If it is in the waist near the airlocks, then the geometry for HLS-to-HLS docking might get interesting.

If you had an Option B active IDA and an Option A passive IDA, that would work.  But I'd think that you'd use two Option B-revised LSSes for this mission.  So it probably needs to be active/passive from the git-go.

This isn't a huge deal, as you said.  But it is a piece of work that would have to be qualified before trying to do either a NASA-funded or private lunar surface mission between Arty 3 and 4.

If HALO was ready but Block 1B wasn't, NASA could do the commissioning  work with an LEO-NRHO-LEO LSS and and F9/D2.  Then you could dock a second LSS at the Gateway and do the lunar surface mission at the same time.  Again, not something that Congress and Boeing/LockMart/NorGrum would appreciate, but ESA might.

Online DanClemmensen

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #184 on: 03/14/2023 05:13 pm »

If HALO was ready but Block 1B wasn't, NASA could do the commissioning  work with an LEO-NRHO-LEO LSS and and F9/D2.  Then you could dock a second LSS at the Gateway and do the lunar surface mission at the same time.  Again, not something that Congress and Boeing/LockMart/NorGrum would appreciate, but ESA might.
Not sure what you mean. Did you mean I-HAB? PPE/HALO will be integrated on Earth and launched as a unit on an FH.

How do you propose to get I-HAB to NRHO and dock it to HALO? I'm sure there's a way, I just don't know what you have in mind. The current plan is to launch HALO in the same SLS 1B as Orion. Orion will dock to I-HAB and then dock the I-HAB/Orion complex to PPE/HALO.

I think PPE/HALO has three available IDSS ports (two radial, one axial, all passive-only(?). This is enough to allow Orion and HLS to both dock to PPE/HALO, assuming the geometry works.

Online jarmumd

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #185 on: 03/14/2023 06:34 pm »
Minor Nitpicks for the general audience.

IDA - International Docking Adapter - This is a specific piece of hardware which adapts the APAS on the ISS/PMA to the IDSS standard.  It does not exist outside of the ISS, attached to the two PMA's on the forward and zenith ports.

IDSS vs GDSS - Gateway will use the Gateway Docking System Standard, which has mostly the same geometry, but has different umbilical (and has fluid) connectors. 

I thought that HALO will use the NASA Docking System - Block 2 - Passive, which is a Boeing product (the Active is used on CST-100 (Block1) and Orion (Block2) ).  Likewise, I assumed the european modules would use some form of passive or androgyneous IBDM.

Online DanClemmensen

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #186 on: 03/14/2023 07:18 pm »
Minor Nitpicks for the general audience.

IDA - International Docking Adapter - This is a specific piece of hardware which adapts the APAS on the ISS/PMA to the IDSS standard.  It does not exist outside of the ISS, attached to the two PMA's on the forward and zenith ports.

IDSS vs GDSS - Gateway will use the Gateway Docking System Standard, which has mostly the same geometry, but has different umbilical (and has fluid) connectors. 

I thought that HALO will use the NASA Docking System - Block 2 - Passive, which is a Boeing product (the Active is used on CST-100 (Block1) and Orion (Block2) ).  Likewise, I assumed the european modules would use some form of passive or androgyneous IBDM.
I'm a bit unclear on how Gateway modules connect to each other versus the ports that are exposed for docking to visiting spacecraft. In particular, What sort of connections is used to hook I-HAB to HALO? It only has to connect once and then it will never disconnect.

What port is required on the HLS to connect to Gateway? I thought it was active IDSS.

I thought NDS block 2 implemented IDSS.


Offline whitelancer64

Minor Nitpicks for the general audience.

IDA - International Docking Adapter - This is a specific piece of hardware which adapts the APAS on the ISS/PMA to the IDSS standard.  It does not exist outside of the ISS, attached to the two PMA's on the forward and zenith ports.

IDSS vs GDSS - Gateway will use the Gateway Docking System Standard, which has mostly the same geometry, but has different umbilical (and has fluid) connectors. 

I thought that HALO will use the NASA Docking System - Block 2 - Passive, which is a Boeing product (the Active is used on CST-100 (Block1) and Orion (Block2) ).  Likewise, I assumed the european modules would use some form of passive or androgyneous IBDM.

GDSS is mentioned in the NextSTEP-2 HLS Appendix H BAA from 2019 (also attached for reference):

"In its FFP proposal, the Offeror shall propose a design that enables HLS docking to transport the crew from either Gateway or Orion. For docking with the Gateway, Offerors shall include development of an International Docking System Standard (IDSS) and Gateway Docking System Standard (GDSS)-compliant Active-Active docking adapter or equivalent approach for successful docking, as well as delivery and attachment of the adapter to Gateway. For docking with Orion, Offerors shall include development of a passive docking system or equivalent approach for successful docking, as well as delivery and attachment of the system on HLS.

Note that NASA anticipates awarding up to two contracts with performance continuing through 2024 flight demonstration. If the use of the adapter flown during the first contractor mission is successful and if the second contractor mission architecture supports an adapter, the first contractor’s adapter will remain attached to Gateway, and the Government will take ownership of the adapter after completion of the demonstration mission. That adapter would then be used for subsequent missions by both awarded contractors. In this scenario, the second contractor’s adapter would become a flight spare, to be delivered to the Government prior to the end of Option B (if exercised) or Option A (if Option B is not exercised). If the first or second contractor’s architectures use Orion as a crew transfer, the contractors will each require separate docking systems that will need to be delivered via each Contractor’s respective HLS capability."

This is the only part of the document that mentions the Gateway Docking System Standard.
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Online jarmumd

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #188 on: 03/14/2023 07:34 pm »
Minor Nitpicks for the general audience.

IDA - International Docking Adapter - This is a specific piece of hardware which adapts the APAS on the ISS/PMA to the IDSS standard.  It does not exist outside of the ISS, attached to the two PMA's on the forward and zenith ports.

IDSS vs GDSS - Gateway will use the Gateway Docking System Standard, which has mostly the same geometry, but has different umbilical (and has fluid) connectors. 

I thought that HALO will use the NASA Docking System - Block 2 - Passive, which is a Boeing product (the Active is used on CST-100 (Block1) and Orion (Block2) ).  Likewise, I assumed the european modules would use some form of passive or androgyneous IBDM.
I'm a bit unclear on how Gateway modules connect to each other versus the ports that are exposed for docking to visiting spacecraft. In particular, What sort of connections is used to hook I-HAB to HALO? It only has to connect once and then it will never disconnect.

What port is required on the HLS to connect to Gateway? I thought it was active IDSS.

I thought NDS block 2 implemented IDSS.

AFAIK, all Gateway element connect via docking.  Any passive port (like those on HALO), will need an active to connect.  So I think that means that I-HAB will need an active docking system on at least one side.  This is also why at one point HLS was suggesting the use of an Active-Active docking adapter, so that a passive HLS could mate with an active docking port on an adapter which also had an active docking port to connect to gateway.

It's not clear to me if NDS-B2 is only GDSS, or if it can be build in IDSS or GDSS versions.

Offline TheRadicalModerate

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #189 on: 03/14/2023 08:57 pm »
Not sure what you mean. Did you mean I-HAB? PPE/HALO will be integrated on Earth and launched as a unit on an FH.

Yes, I meant I-Hab.  Sorry.

Quote
How do you propose to get I-HAB to NRHO and dock it to HALO? I'm sure there's a way, I just don't know what you have in mind. The current plan is to launch HALO in the same SLS 1B as Orion. Orion will dock to I-HAB and then dock the I-HAB/Orion complex to PPE/HALO.

I was assuming that ESA would eventually bail on co-manifesting and launch it on a CLV.  It's not a particularly challenging payload.

Quote
I think PPE/HALO has three available IDSS ports (two radial, one axial, all passive-only(?). This is enough to allow Orion and HLS to both dock to PPE/HALO, assuming the geometry works.

Ah, I was wondering about this.  So you could theoretically dock one LSS to the HLS port, and one to the port where I-Hab is going.  (Note that if the HALO-to-I-Hab port is a passive IDA port, that means that I-Hab itself has to be active, but that seems reasonable.)  That only requires LSS active ports.

IIRC, HALO commissioning was supposed to be part of the I-Hab commissioning process.  I don't know whether they've done anything to HALO that makes its commissioning dependent on I-Hab being there or not.  (Where are the initial consumables coming from?)  If not, then it sounds like you could use HALO as-is for two LSSes, commission it, and then proceed to do the Option B mission.  As a safety measure, having the ability to do both LSS-to-LSS and two LSSes-to-Gateway gives you some options if you have a docking problem with one or the other.

Politically, I suspect that SpaceX doesn't want to hoist the Jolly Roger on SLS until Option B is completely proved out.  But if Arty 4 slips into 2028 and that mission is given to the SLD provider, then SpaceX doesn't get Option B HLS proven until Arty 5 in 2029 or 2030.  I'm not sure if Elon has that kind of patience.  But it's probably too expensive a mission for 4 private folks to pay for all of it, so SpaceX would have to eat a lot of the cost.  Might be worth it to them, though.

Again, I doubt that a few extra hooks and some software would deter SpaceX from doing an active/passive LSS-to-LSS docking system, which would avoid using Gateway entirely.  So there's a calculation that NASA and Congress have to make about the PR of having SpaceX go it alone on a lunar surface mission without some pieces-parts of NASA's architecture entangled in the effort.  And if Arty 4 is really sliding further to the right, reallocating a couple hundred million of its budget for FY26 might be prudent.  But that would require congressional approval. I'm not sure whether the penny has dropped for those guys.  But that penny will gain a lot of kinetic energy the longer they wait to adjust to reality.

Online DanClemmensen

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #190 on: 03/14/2023 09:07 pm »

GDSS is mentioned in the NextSTEP-2 HLS Appendix H BAA from 2019 (also attached for reference):

"In its FFP proposal, the Offeror shall propose a design that enables HLS docking to transport the crew from either Gateway or Orion. For docking with the Gateway, Offerors shall include development of an International Docking System Standard (IDSS) and Gateway Docking System Standard (GDSS)-compliant  or equivalent approach for successful docking, as well as delivery and attachment of the adapter to Gateway. For docking with Orion, Offerors shall include development of a passive docking system or equivalent approach for successful docking, as well as delivery and attachment of the system on HLS.

Note that NASA anticipates awarding up to two contracts with performance continuing through 2024 flight demonstration. If the use of the adapter flown during the first contractor mission is successful and if the second contractor mission architecture supports an adapter, the first contractor’s adapter will remain attached to Gateway, and the Government will take ownership of the adapter after completion of the demonstration mission. That adapter would then be used for subsequent missions by both awarded contractors. In this scenario, the second contractor’s adapter would become a flight spare, to be delivered to the Government prior to the end of Option B (if exercised) or Option A (if Option B is not exercised). If the first or second contractor’s architectures use Orion as a crew transfer, the contractors will each require separate docking systems that will need to be delivered via each Contractor’s respective HLS capability."

This is the only part of the document that mentions the Gateway Docking System Standard.

This appears to say that the HLS vendor is responsible for delivery of a chunk of hardware (the "Active-Active docking adapter") That will become a permanent part of Gateway. It has an active GNSS port on one end that will connect to a passive GNSS port and remain permanently attached thereafter, and it will have an active IDSS port on the other end that allows any spacecraft with a passive IDSS port to connect to it, specifically including the HLS.

This is totally screwed up, but you can see how it happened. It results in an HLS that can have a passive-only IDSS port that can connect either to this adapter or to Orion. a passive-only port is the simplest and lowest-mass form of the IDSS port. The problem is: how is the HLS vendor supposed to deliver this strange adapter thingee to Gateway and how it is supposed to be installed? It also results in a weird arrangement where the active HW is part of the station, not the visiting spacecraft, even though the spaceraft will be taking the actual active (i.e., maneuvering) role in the docking.

I had always assumed that SpaceX would use the "escape clause" ("or equivalent approach") to get out of this mess.

Offline tbellman

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #191 on: 03/14/2023 09:30 pm »
How do you propose to get I-HAB to NRHO and dock it to HALO? I'm sure there's a way, I just don't know what you have in mind. The current plan is to launch HALO in the same SLS 1B as Orion. Orion will dock to I-HAB and then dock the I-HAB/Orion complex to PPE/HALO.

I was assuming that ESA would eventually bail on co-manifesting and launch it on a CLV.  It's not a particularly challenging payload.

You worry about RPOD operations for depots in high-elliptic orbits, but you think nothing of having I-HAB, which lacks propulsion of its own, insert itself into NRHO, and rendez-vous and dock with PPE/HALO?  Because that's the problem: without Orion or some other tug, I-HAB will just be a dead mass, and wander eternally beteen the Earth and the Moon like a deep space Flying Dutchman.

I-HAB is sized so it can fit on a Falcon Heavy, together with some kind of tug, but since they then decided to go with comanifesting it on an SLS, they have not developed or procured any such tug.

Offline TheRadicalModerate

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #192 on: 03/14/2023 09:32 pm »
This appears to say that the HLS vendor is responsible for delivery of a chunk of hardware (the "Active-Active docking adapter") That will become a permanent part of Gateway. It has an active GNSS port on one end that will connect to a passive GNSS port and remain permanently attached thereafter, and it will have an active IDSS port on the other end that allows any spacecraft with a passive IDSS port to connect to it, specifically including the HLS.

This is totally screwed up, but you can see how it happened. It results in an HLS that can have a passive-only IDSS port that can connect either to this adapter or to Orion. a passive-only port is the simplest and lowest-mass form of the IDSS port. The problem is: how is the HLS vendor supposed to deliver this strange adapter thingee to Gateway and how it is supposed to be installed? It also results in a weird arrangement where the active HW is part of the station, not the visiting spacecraft, even though the spaceraft will be taking the actual active (i.e., maneuvering) role in the docking.

The vendor is only responsible if they can only afford the mass of the passive IDSS implementation on the NRHO-LS-NRHO leg.  I suspect the thinking is that there can be some mass margin in the launcher when it's hauling the AE or DAE out to the Gateway from LEO, so the AE sticks the AADA on the Gateway when it docks for the first time and leaves it when it undocks.  That way you only have to land on the surface with a low-mass passive IDSS implementation.

The maneuvering vehicle having a passive element also struck me as weird, but it's just a GN&C transform--I think.  As long as they don't have the Boeing guy who did the Starliner RCS transforms working on it, it should be OK.

Quote
I had always assumed that SpaceX would use the "escape clause" ("or equivalent approach") to get out of this mess.

Yeah I'd expect them to go with an active/passive IDSS- or GDSS-compliant dock as opposed to using an AADA.  They need that to dock LSS-to-LSS, which seems like a capability they'd want sooner rather than later.

I can't find an actual GDSS spec.  I'm assuming that it's a superset of IDSS, and has the ability to accommodate an IDSS implementation.  It would obviously be missing all the fancy fluid transfer capabilities.  But my guess is that SpaceX has different plans for how fluids get transferred to an LSS.

Offline TheRadicalModerate

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #193 on: 03/14/2023 09:39 pm »
How do you propose to get I-HAB to NRHO and dock it to HALO? I'm sure there's a way, I just don't know what you have in mind. The current plan is to launch HALO in the same SLS 1B as Orion. Orion will dock to I-HAB and then dock the I-HAB/Orion complex to PPE/HALO.

I was assuming that ESA would eventually bail on co-manifesting and launch it on a CLV.  It's not a particularly challenging payload.

You worry about RPOD operations for depots in high-elliptic orbits, but you think nothing of having I-HAB, which lacks propulsion of its own, insert itself into NRHO, and rendez-vous and dock with PPE/HALO?  Because that's the problem: without Orion or some other tug, I-HAB will just be a dead mass, and wander eternally beteen the Earth and the Moon like a deep space Flying Dutchman.

I-HAB is sized so it can fit on a Falcon Heavy, together with some kind of tug, but since they then decided to go with comanifesting it on an SLS, they have not developed or procured any such tug.

Ahhhhh, that's the problem.  Of course.  Thanks.

So they'd need a transfer vehicle with ~150m/s of delta-v to get it docked without the Orion.  Yeah, that makes it more complicated.

However, I have this feeling that the NorGrum-Dynetics team probably has a plan for a naked Cygnus bus for delivering prop tanks.  That wouldn't be the most mass-efficient implementation ever, but that plus the I-Hab could be launched by an FHE.

Offline clongton

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #194 on: 03/14/2023 09:47 pm »
According to the FY24 NASA Budget request, Artemis III is now December 2025 and Artemis IV is now September 2028 <snip>

Almost 3 years between flights!
Further proof that Artemis is NOT a true exploration plan.

I am not sure that it's proof of that. Artemis IV has a lot of new elements to it including the EUS and ML2. It seems likely that Artemis III will slip into 2026. As Eric Berger mentioned before, it might be better to let Artemis III slip into 2026 to avoid a 3 year gap.

Sure it is. Even with a slip to 2026 it's still a 2 year gap.
So 2 guys on the surface for 5 days once every 2 years is an exploration plan?
I don't think so.
« Last Edit: 03/14/2023 09:56 pm by clongton »
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Online DanClemmensen

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #195 on: 03/14/2023 09:53 pm »
How do you propose to get I-HAB to NRHO and dock it to HALO? I'm sure there's a way, I just don't know what you have in mind. The current plan is to launch HALO in the same SLS 1B as Orion. Orion will dock to I-HAB and then dock the I-HAB/Orion complex to PPE/HALO.

I was assuming that ESA would eventually bail on co-manifesting and launch it on a CLV.  It's not a particularly challenging payload.

You worry about RPOD operations for depots in high-elliptic orbits, but you think nothing of having I-HAB, which lacks propulsion of its own, insert itself into NRHO, and rendez-vous and dock with PPE/HALO?  Because that's the problem: without Orion or some other tug, I-HAB will just be a dead mass, and wander eternally beteen the Earth and the Moon like a deep space Flying Dutchman.

I-HAB is sized so it can fit on a Falcon Heavy, together with some kind of tug, but since they then decided to go with comanifesting it on an SLS, they have not developed or procured any such tug.

Ahhhhh, that's the problem.  Of course.  Thanks.

So they'd need a transfer vehicle with ~150m/s of delta-v to get it docked without the Orion.  Yeah, that makes it more complicated.

However, I have this feeling that the NorGrum-Dynetics team probably has a plan for a naked Cygnus bus for delivering prop tanks.  That wouldn't be the most mass-efficient implementation ever, but that plus the I-Hab could be launched by an FHE.
Use a DragonXL for the tug. This does require yet another FH mission in addition to the FH used for the I-Hab. Dragon XL must already be able to do autonomous RPOD and must already have an active IDSS axial port.

For me, using any autonomous tug to dock the tug+I-Hab to PPE+HALO just seems magical because the thrusters are so far away from the port being docked, but I'm not a rocket scientist and therefore my visualization of this maneuver is probably faulty.

Offline tbellman

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #196 on: 03/14/2023 09:57 pm »
This is totally screwed up, but you can see how it happened. It results in an HLS that can have a passive-only IDSS port that can connect either to this adapter or to Orion. a passive-only port is the simplest and lowest-mass form of the IDSS port. The problem is: how is the HLS vendor supposed to deliver this strange adapter thingee to Gateway and how it is supposed to be installed?

That would not be a problem.  The lander would be launched with the AADA (Active/Active Docking Adaptor) attached to its docking port.  It would then rendez-vous and dock with the Lunar Gateway; specificially of course the free active port on the AADA would dock to the designated passive port on the Gateway.  Easy-peasy.  Then Orion arrives, docks to one of the remaining (passive) ports on LOP-G, crew transfers to the lander, lander undocks from the AADA and goes down to the lunar surface.  When the lander comes back to NRHO, it can either dock with the AADA which is now attached to the Gateway, or to Orion.

Quote from: DanClemmensen
It also results in a weird arrangement where the active HW is part of the station, not the visiting spacecraft, even though the spaceraft will be taking the actual active (i.e., maneuvering) role in the docking.

Irrelevant.  The docking surfaces only care about actual relative movements, not which side provides propulsion.

Quote from: DanClemmensen
I had always assumed that SpaceX would use the "escape clause" ("or equivalent approach") to get out of this mess.

In my opinion, SpaceX is almost certainly going to make an androgynous docking mechanism on HLS Starship.  (The HLS Requirements Document, HLS-RQMT-001, is by the way explicit in that the alternative to an AADA, is an androgynous docking mechanism.)

Online jarmumd

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #197 on: 03/14/2023 09:59 pm »
I can't find an actual GDSS spec.  I'm assuming that it's a superset of IDSS, and has the ability to accommodate an IDSS implementation.  It would obviously be missing all the fancy fluid transfer capabilities.  But my guess is that SpaceX has different plans for how fluids get transferred to an LSS.

It doesn't appear to be public yet.  I assume they plan on releasing it as part of the www.internationaldeepspacestandards.com (like is done for the www.internationaldockingstandard.com).  That one, Rev F, shows all the locations for the umbilicals and fluids for GDSS, but what isn't shown are details about the umblicals (which are different).  So, as far as I'm aware, IDSS and GDSS systems can make a pressure seal, but not transfer power and data.  I was under the impression that the GDSS fluid transfer specification was most critical to re-fueling the PPE?

Online DanClemmensen

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #198 on: 03/14/2023 10:14 pm »
This is totally screwed up, but you can see how it happened. It results in an HLS that can have a passive-only IDSS port that can connect either to this adapter or to Orion. a passive-only port is the simplest and lowest-mass form of the IDSS port. The problem is: how is the HLS vendor supposed to deliver this strange adapter thingee to Gateway and how it is supposed to be installed?
That would not be a problem.  The lander would be launched with the AADA (Active/Active Docking Adaptor) attached to its docking port.  It would then rendez-vous and dock with the Lunar Gateway; specificially of course the free active port on the AADA would dock to the designated passive port on the Gateway.  Easy-peasy.  Then Orion arrives, docks to one of the remaining (passive) ports on LOP-G, crew transfers to the lander, lander undocks from the AADA and goes down to the lunar surface.  When the lander comes back to NRHO, it can either dock with the AADA which is now attached to the Gateway, or to Orion.
I think that was the intent of the RFP when the lander was a little toy system to be launched in one or more pieces carried as more or less conventional payloads inside fairings. It does not work well for a Starship HLS, which would somehow need to launch from Earth with the AADA stuck on its nose or something.


Offline Phil Stooke

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Re: NASA's Artemis Program Updates and Discussion Thread 5
« Reply #199 on: 03/14/2023 10:18 pm »
"Further proof that Artemis is NOT a true exploration plan."

You get what you are willing to pay for.  Artemis could easily become a true exploration plan if it's given the resources.
Professor Emeritus, University of Western Ontario. Space exploration and planetary cartography, historical and present. A longtime poster on
unmannedspaceflight.com (RIP - now archived at https://umsfarchive.com/index.php/), now posting content on https://mastodon.social/@PhilStooke and https://discord.com/channels/1290524907624464394 as well as here. The Moon Chronicle, a new history of lunar exploration (free download): https://publish.uwo.ca/~pjstooke/moon-chronicle.htm  The Solar System ain't gonna map itself.

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