SpaceX and Replacement of Russian module services on the ISS

[Comga]

Cygnus or MEV type would make a better system.

So might HTV-X.
And since we are discussing systems not currently flying, we could include the SNC Shooting Star.

Assertions like the one above with no criteria or other information are "references to authority".
No matter how much we respect Jim for his proven insight and insider information, just throwing that out doesn't add to the discussion.
This is not saying "wrong!"
It's asking how either of those could be produced as  a "better" comprehensive solution in a reasonable time for a reasonable cost.
Can you explain how and why Cygnus or MEV would be better?

But....
"Better is the enemy of good enough"

"Better" is also why many things stagnated for decades.  Trying to make perfect systems always fails.
Atlas-V is "better" than Falcon 9 by many metrics, but it misses on several including cost and now availability
SLS is "better" than Falcon Heavy in throw weight and other metrics, but it will have taken 2 to 5 times as long between announcement and first flight, be more than ten times as expensive, and have no flexibility of production.

"Better" should be a global metric.
It includes a supplier who comes up with creative and effective solutions quickly.

What examples do we have of quick and effective developments for spacecraft requirements?

[Jorge]

Ok, good to know.
If you were to redesign the ICM for the ISS's international segment as it is now, how would you do it?

Can't

Can't is a pretty strong statement. But I agree it's not really practical (or maybe even practicable).

First, groundrules: ICM was originally meant to attach to the aft end of FGB (the probe on the aft end of FGB would have to be replaced with a passive APAS first). Detaching the Russian modules isn't going to happen. So it needs to attach to Node 2 Forward, and ISS would have to yaw 180 degrees for each reboost (no big deal, it did so for space shuttle reboosts).

So, list of mods off the top of my head:
1) Gut the interior to accommodate a pressurized tunnel with hatches, so that Dragon and Starliner can dock to ICM Forward and the crew can pass through to the rest of the station. This will require rebuilding the propellant tanks, of course, since they're currently in the way. The module will also get bigger if you want to keep the same propellant capacity (and you will, if not more).
2) Replace the APAS docking hardware with NDS (but even then, you need mods, if you're serious about ICM being anything other than "interim", as I'll get to later).
3) Upgrade the ICM GNC software to accommodate desat commanding from ISS via the NDS 1553 bus (ICM was originally designed for purely propulsive attitude control, which will deplete the tanks quickly trying to control today's much larger ISS).
4) The ICM roll thrusters don't have enough control authority considering ISS's colossal roll moment of inertia. Consider lengthening the deployable booms the thrusters are mounted on, to increase the control moment.
Saving possibly the biggest two for last,
5) The ICM propellant tanks aren't refillable, and the current NDS docking interface doesn't support fluid transfer. The US as a whole has never demonstrated in-space hypergolic propellant transfer, so this is a fairly sizable R&D item. Again, this is only if you expect ICM to be anything other than "interim".
6) You need a way to get ICM to ISS. Originally ICM would have ridden up in the shuttle payload bay, be berthed to the ODS by the RMS, then docked to the FGB. So it didn't need any active rendezvous/prox ops/docking capability. Whether you have ICM deliver itself, or have another vehicle (e.g. Dragon or Starliner) do it, you'll need active rendezvous sensors on the ICM active NDS side, and passive docking aids on the passive NDS side. If ICM delivers itself, the ICM GNC system needs to be upgraded to be capable of rendezvous/prox ops/docking, otherwise it needs a 1553 pass-through to get the data from the ICM rendezvous sensors to whatever vehicle is delivering it (and that vehicle's rendezvous GNC system has to be upgraded to accept sensor data from an external source, and be able to control itself with the ICM mounted on front).

Not impossible, but I'm hard pressed to state what, if any, original ICM hardware would remain after all these upgrades. Better to start with a clean sheet.

[Jim]

Not impossible, but I'm hard pressed to state what, if any, original ICM hardware would remain after all these upgrades. Better to start with a clean sheet.

That is why I say "can't".  It isn't an ICM anymore. 

[Jim]

Right now, in 2022, is there any organization with the right combination of assets (human and machine) more qualified to tackle this than SpaceX? I can't think of one.

Yes, NG, Maxar, or LM.  Not going to say Boeing.

NG has Cygnus and MEV.  Maxar has its electric buses. 

LM has SSB.

[JayWee]

It might not be either/or. But a collaborative effort.

[JayWee]

The reason SpaceX is mentioned so much for any solutions is they are the only reliable launcher with plenty of rockets to get things to the ISS.  They also have a lot of different equipment.  Dragon I's, Dragon II's, Draco's, Super Draco's, empty trunks, reusable supply of boosters.  They can make plenty of second stages.  They can hold back on Starlink launches if ISS needs something launched.  They also have Falcon Heavy.  They are more than capable to help with ISS.  They can launch for other competitors with maybe very little adaption. 

Antares is hurt because of Ukraine for a launcher.

BE-4 is late, thus Vulcan and New Glenn. 

All Atlas V's are contracted for launches.

No more Delta IV's to be launched.  Even in production can resume, what about RS-68, can it be resumed? 

Neutron is not ready. 

No one else right now has the capability to get something done quickly with ISS, except SpaceX. 

I'd say it could be theoretically be possible to exchange some Amazon Atlas V's for delay in the constellation deployment time limit.

But even then - how long does it take from order to launch for Atlas V ? Swapping Starlink launch scheduled few weeks away for something, I guess, is a matter of a phone call.

[Jeff Lerner]

Things seem to moving at breakneck speed…all the proposed solutions here seem to require weeks, months, etc…what happens if Putin decides within days to shut the RUssian segments of ISS down ?

I know the Astronauts and cosmonauts and support centres are all consummate professionals but does anyone have any idea what the current state of ISS Crew relations are ?..must be very difficult to float by a crew member without saying something about what’s going on ..

[Surfdaddy]

If Starliner had not been pathetically late, perhaps it could have helped reboosts.
Alas.

[Baldr]

Cygnus or MEV type would make a better system.

I'm curious as to why (in this thread) you haven't yet claimed that:

A) PMA-1 cannot be undocked from Zarya
B) PMA-1 cannot be unberthed from Unity

In the thread below*, I was attacked by you and others for daring to suggest that A) and B) is possible.

*snip*

A. The motor drivers that drove the 16 bolts that connect PMA-1 to Zarya were externally controlled via cables that ran to the Shuttle (STS-88). These cables were removed during the second ISS assembly spacewalk, and probably no longer exist. There is no way to control these bolts from within the ISS, so effectively, PMA-1 and Zarya are permanently joined together.

"The last task for today will be to disconnect and stow cables that were used by Endeavour's crew to control the docking mechanism, called the Androgynous Peripheral Attach System (APAS), that docked Zarya to Unity earlier in the mission. With that system never again to be opened, the cable used by Endeavour to control it, which runs along Pressurized Mating Adapter 2 (PMA 2), will be disconnected on this spacewalk"

https://science.ksc.nasa.gov/shuttle/missions/sts-88/sts-88-day-07-highlights.html

B. PMA-1 was installed on Unity / Node 1 on the ground, before launch on STS-88. It was never meant to be removed from Unity, so I presume it also was permanently installed with no reasonable way to remove it from Unity via a spacewalk. However, I don't know the details of its installation. Perhaps someone else can chime in with details.

The cables went from the APAS on PMA-2 to the APAS on PMA-1. When the APAS on PMA-2 was docked to the APAS on the ODS, Unity could receive power from Endeavour (through APAS) and the APAS on PMA-1 could be controlled from the cockpit (cabling signal transmitted through the two docked APAS systems on ODS/PMA-2).

Full Quote: The last task for today will be to disconnect and stow cables that were used by Endeavour's crew to control the docking mechanism, called the Androgynous Peripheral Attach System (APAS), that docked Zarya to Unity earlier in the mission. With that system never again to be opened, the cable used by Endeavour to control it, which runs along Pressurized Mating Adapter 2 (PMA 2), will be disconnected on this spacewalk as a "get-ahead task" for future assembly missions when PMA 2, currently the adapter to which Endeavour is docked, will be moved.

-

Now, I can't see why it's not possible to route new cables -- for which I assume the blueprints still exists -- to the APAS on PMA-1 and with the cabling routed through, say, a docked cargo vehicle and into the interior of the ISS where the undocking would be controlled from.

Quite a few of the components on the HST were also not designed to be replaced, yet several spacewalks were undertaken that were originally not planned for.

[Baldr]

Things seem to moving at breakneck speed…all the proposed solutions here seem to require weeks, months, etc…what happens if Putin decides within days to shut the RUssian segments of ISS down ?

I know the Astronauts and cosmonauts and support centres are all consummate professionals but does anyone have any idea what the current state of ISS Crew relations are ?..must be very difficult to float by a crew member without saying something about what’s going on ..

Yesterday, I suggested to use the Artemis 1 spacecraft (Orion capsule and service module) to replace, at least, the attitude control and desaturation maneuvers (CMG) of the Russian Segment. What's important would be to get the Artemis 1 docked to the ISS ASAP. What is valuable is the Service Module and not the Orion capsule.

https://forum.nasaspaceflight.com/index.php?topic=55882.0

[Brovane]

Right now, in 2022, is there any organization with the right combination of assets (human and machine) more qualified to tackle this than SpaceX? I can't think of one.

Yes, NG, Maxar, or LM.  Not going to say Boeing.

NG has Cygnus and MEV.  Maxar has its electric buses. 

LM has SSB.

I think in this instance the interests of all the parties involved would be best served by SpaceX just being the launch provider. 

[butters]

No one else right now has the capability to get something done quickly with ISS, except SpaceX.

Perhaps no one else right now has the capability to launch something (other than Starliner) to the ISS, but others have spacecraft that could be launched on Falcon 9, and one or more of them are closer to filling the capability gaps than SpaceX is with Dragon. Northrop Grumman, for example, is not going to turn down a NASA contract for ISS propulsion / attitude control just because they might have to launch their spacecraft on Falcon 9. We haven't somehow transitioned into an era where only complete vertical solutions need apply.

[nacnud]

There's definitely a lot of that.

But the solution is simple.

No, it isn't

Most of these guys are fixated on reboost and that isn't even the hardest problem (though it is plenty hard). CMG desat is. It's harder because it has to be more tightly integrated into ISS GNC.

ISS is many months away from decaying to the "no-return" altitude. But at any given time, if the CMGs saturate and there are no thrusters to desat, ISS loses attitude control and from that point its power/thermal lifetime is measured in days, if not hours.

I believe that atmo drag (maybe light pressure, whichever) can be used to achieve CMG desat, cunning orientation of the station is required. Cygnus can then be used for reboot.

That should give time for someone to build something.

[Lee Jay]

There's definitely a lot of that.

But the solution is simple.

No, it isn't

Most of these guys are fixated on reboost and that isn't even the hardest problem (though it is plenty hard). CMG desat is. It's harder because it has to be more tightly integrated into ISS GNC.

Thanks for answering my previous question, Jorge. I have another.

How often do desats typically have to happen or is that heavily dependent on atmosphere and orientation?

[Jim]

Right now, in 2022, is there any organization with the right combination of assets (human and machine) more qualified to tackle this than SpaceX? I can't think of one.

Yes, NG, Maxar, or LM.  Not going to say Boeing.

NG has Cygnus and MEV.  Maxar has its electric buses. 

LM has SSB.

I think in this instance the interests of all the parties involved would be best served by SpaceX just being the launch provider.

Not true either.

[Jim]

Things seem to moving at breakneck speed…all the proposed solutions here seem to require weeks, months, etc…what happens if Putin decides within days to shut the RUssian segments of ISS down ?

I know the Astronauts and cosmonauts and support centres are all consummate professionals but does anyone have any idea what the current state of ISS Crew relations are ?..must be very difficult to float by a crew member without saying something about what’s going on ..

Yesterday, I suggested to use the Artemis 1 spacecraft (Orion capsule and service module) to replace, at least, the attitude control and desaturation maneuvers (CMG) of the Russian Segment. What's important would be to get the Artemis 1 docked to the ISS ASAP. What is valuable is the Service Module and not the Orion capsule.

https://forum.nasaspaceflight.com/index.php?topic=55882.0

No, the Service module doesn’t [have] the thrusters to do Desat

[Jim]

No one else right now has the capability to get something done quickly with ISS, except SpaceX.

Perhaps no one else right now has the capability to launch something (other than Starliner) to the ISS, but others have spacecraft that could be launched on Falcon 9, and one or more of them are closer to filling the capability gaps than SpaceX is with Dragon. Northrop Grumman, for example, is not going to turn down a NASA contract for ISS propulsion / attitude control just because they might have to launch their spacecraft on Falcon 9. We haven't somehow transitioned into an era where only complete vertical solutions need apply.

Atlas is available inf needed.

[butters]

Atlas is available inf needed.

I should hope Bezos would be so accommodating as to trade one of Kuiper's Atlases for a Vulcan if it's necessary to keep the ISS in orbit. It would be a real heel turn if he made a fuss about that.

[zubenelgenubi]

I'm curious as to why (in this thread) you haven't yet claimed that:

A) PMA-1 cannot be undocked from Zarya
B) PMA-1 cannot be unberthed from Unity

In the thread below*, I was attacked by you and others for daring to suggest that A) and B) is possible.
<snip>
* https://forum.nasaspaceflight.com/index.php?topic=55882.0

Moderator:
No, you were corrected, and you refused to listen.

Yesterday, I suggested to use the Artemis 1 spacecraft (Orion capsule and service module) to replace, at least, the attitude control and desaturation maneuvers (CMG) of the Russian Segment. What's important would be to get the Artemis 1 docked to the ISS ASAP. What is valuable is the Service Module and not the Orion capsule.

https://forum.nasaspaceflight.com/index.php?topic=55882.0

Moderator:
Yes, and you wouldn't listen to the reasons as to why your inkling of a proposal wouldn't work in that thread.

And, you insulted other members, including one who actually has decades of spaceflight engineering experience, resulting in moderator actions against you in that thread.

Just as moderators have taken similar actions against you in this thread.

Bravo. 👏

[zubenelgenubi]

Atlas is available if needed.

I should hope Bezos would be so accommodating as to trade one of Kuiper's Atlases for a Vulcan if it's necessary to keep the ISS in orbit. It would be a real heel turn if he made a fuss about that.

My hypothesis: There is contract language allowing ULA to re-purpose launch vehicle(s) in case of an emergency.

Experts, what say you?