Project Soyuz 7K-T Custom

diogom

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This should be interesting:


Looking forward to the power up and finally a proper look at one of the electroluminescent indicators. And seeing it move, the day/night thing finally makes sense.

Also finally have a proper look at the globe, and seeing Jurvetson's recently posted earlier unit, it's interesting that ASTP's looks so different from both the early version and Soyuz-35, assuming nothing got swapped out post-flight. I'm honestly surprised mine ended up looking so close with just text and like two low res pics. Should only need small adjustments.

There's also the potential here to get some power consumption figures.
 

diogom

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Electroluminescents under update after fresh info:

1677001527949.png

Bluer than I expected, and the "font" is kinda broken up, which I guess has to do with the way the electrodes are made.

Edit:

1677034019630.png
 
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diogom

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Been a bit quiet here, as Orbiter took a bit of a back seat to other hobbies. Anyway, looking to ease back into this again, so might as well drop a small update.

As it stands, the remaining major item is Igla. First step is to establish a scenario that reliably fails, and see what the sequence is. Hopefully there's a fix for the root of the problem, and it doesn't just turn into whack-a-mole with various specific starting conditions.

I might also try to determine what sort of power consumption each of the electroluminescent signals would have. All I know is they take high voltage AC, so would it would require onboard inverters. My plan would be to try to get figures for contemporary technology and take that as good enough. I did manage to get some figures for the analog clock from CuriousMarc, which ended up being somewhat negligible compared to the overal power draw, but I've singled it out anyway. It's basically a 2 Hz square wave with 27 V amplitude, and 100 ms -ish pulses.

To add some colour, here's the full reworked ELS, following the Globe's pattern (which can now be seen here). There is glass in the mesh, and compared to the Globe's signal it's making it a bit harder to read, so I might reconsider that decision since it's otherwise invisible (duh) without any reflections and thus adding nothing of value.

1681855439457.png

Also reworked the IKP with the new blue:

1681855697390.png
 

diogom

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Alright, my last post aged like milk. The Igla issue I and thermocalc (and probably everyone else who tried it) had was an easy fix, just a dumb if as I imagined. But that didn't make it work either and after testing, it opened the floodgates of questioning whether it can ever reliably work in its present form. There's so much dancing around, pitching back and forth. I'm thinking it might need some more major restructuring to focus more on that 90º pitch down attitude as the default orientation until 1 km -ish, which for all I know indeed was the strategy in real life. It would make for a quicker flip to braking burns and back, less fuel waste, yaw to align with motion of line of sight instead of roll, which is a bit less effective than yaw. And maybe there's a better way of getting the necessary data. But it will take some time to plan and execute, and I find myself again holding back a bunch of other new features already implemented for the one single blocking issue. So I've been thinking a few days, and as much as I dislike going back on it, after checking docking manually remains doable, I've decided to temporarily disable Igla and wrap up this release. I also know better now than to make promises about it for the next one.

All the usual approach info will still be provided on the HUD, provided the mode is """activated""", and Salyut will keep its own Igla working, so it will be a cooperative docking target. As for Soyuz, the old reliable "coast to just before the closest approach and burn retrograde to target" works (with the default Orbiter tools, and Salyut already had an IDS too), and then a small burn towards Salyut to get on final approach, keeping on track with DPO. The requirement of course is that the closest approach is short, within, say, 5 km.

As for the rest, I've closed up all the new english translations and just need to update the Guide to reflect this and all the relevant new stuff (electrical system, programs, etc), so I expect to have something out soon.
 

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[...]So I've been thinking a few days, and as much as I dislike going back on it, after checking docking manually remains doable, I've decided to temporarily disable Igla and wrap up this release. I also know better now than to make promises about it for the next one.[...]
Quality over quantity! That's nothing to apologize for (y)
 

diogom

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Agreed. It's not that I didn't expect a challenge, but there's a certain irony that attempting this particular system was one of the first concrete ideas when this was all just an idea being entertained. For what it's worth, even in its current form I'm glad to have tried it. On to the next attempt.

Have a few ideas cooking for next steps. The orientation modes have a couple of gremlins that could use a look, though I haven't been able to determine how to reliably trigger them yet. Recently learned/noticed that DPO and DO did not, in fact, have separate propellant supplies. Instead, there were three main tanks of H2O2, from which both DPO and DO drew, and a backup tank to be used when the three mains run out, or have an issue. Being pressure-fed engines, there were also main and backup pressurising gas tanks, one each, containing what I'm guessing was helium. So this calls for a reconfiguration of the tanks, and eventually I'd like to understand how to relate all this to pressure: the KEI would display both H2O2 and gas pressures, in kgf/cm^2 (same for the SKDU, except with fuel and oxidizer). The KEI on Soyuz-TM still retained this, though with the corresponding differences with the integrated fuel system.

Updated

Baikal - 18/05/2023:
  • Basic main/backup battery implementation added, with power drain variation based on active systems on top of base power drain: external lights, IKP, clock
  • Combined power mode and recharge when docked to Salyut (no influence from sun exposure for now)
  • ELS button changed to be all-signal illumination test
  • KSU SSVP signalling only when SSVP power on and show extended/retracted/open/closed, not intermediate states
  • Improvements to SSVP operation
  • IKP: Automatic Descent and Automatic Manoeuvre programs, standby and illumination test modes added
  • BTSI target Delta-V input enabled for IKP Programs
  • Optimisation of VC panel display rendering
  • Vzor central and peripheral screen on/off added
  • Globe texture updated (southern hemisphere latitude labels)
  • Scenario save states for orientation modes, PVU/IKP and BDUS
  • Igla temporarily disabled
  • Documentation updated
 

diogom

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Happy to report XRSound integration started and is going well, after a brief battle with linking libraries to kick off.

Starting with something which definitely won't get annoying at all. Or maybe lull one to sleep:

Don't have much else yet, other than the remaining switches, I've cooked up the alarm sound which will play along with the "АВАРИЯ" signal (and be shut up by the "Sound" button).
 

n72.75

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I like it!
 

diogom

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And there it is, as the remaining Delta-V crosses the 150 m/s threshold:

The alarm is based mostly on this document (Figure 4), which describes it for Soyuz-T and -TM as between 550 and 750 Hz, and on the film Return from Orbit. I found a triangle wave to be a match to what's heard on Return from Orbit, though there the frequency sweep is wider. Currently it's also assigned to the inertial hold mode, when the maximum angle deviations are exceeded and the hold mode is automatically switched off.
 

kuddel

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Nice work implementing the sounds!
Getting them "right" from schematics or technical documentation however is tricky: Even if the generated wave is perfect square/sinosodial/triangle, doesn't mean it would sound like that after it gets out of the "speakers".
Be it old telephone-earpeace, a "regular" speaker driver or a piezo driver influences the "acousics" a lot - think of bandpass, lowpass or whatever.

Audio from movies are not meant to be "real", they have a purpose that is important in movies - they are not "documentaries" in that case.

Another source might be recordings on youtube from actual simulations like this here for example (round 2:26 in):


This is not the correct Soyuz model I believe, but maybe you can find something much better out there ;)

Nevertheless, keep up the good work!
 

diogom

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True! To be honest, I'm only using the movie as a "secondary" source for sounds, in that it kinda supports the "technical" information, but doesn't necessarily stand by itself. However, they did film aboard Salyut 7 and Soyuz T-9 (source seems to indicate while it was in pre-launch testing), and I'm assuming on training simulators for the by then outdated Soyuz 7K. So that gives it some credibility relatively speaking, though still not complete trust, since who says a certain sound isn't just "ADR" from some other source (in that specific scene in question, it most certainly was dubbed at least), or a certain visual isn't a reconstructed set.

Although at least for the alarm, the fundamental frequency was the more important aspect to approximate for me, which the movie does contradict slightly anyway. Even if the signal started life as a "perfect" sine wave, unlikely it would still be by the time it reaches the ear. Filtering is a good tip I hadn't thought of and is doable if certain types of speakers' frequency responses are known, generally speaking, though it would be another layer of guessing, in this case what type of speakers were present and how good they were.

Unfortunately, recordings from that era are very limited in quantity, and quality where they exist, so usually the best I can do is make best guesses. I've long accepted that's the best I can reach for the vast majority of aspects. Fortunately, some things have remained mostly the same or can probably be assumed to have, and material is more abundant for the more modern versions (exhibit A, the linked video. And for all I know, 7k had a beep instead of a siren!). One piece of low hanging fruit I also thought of is the cabin sound, and here Oleg Artemyev's channel might be useful.
 

diogom

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Slow month, just a short update. Reworked the RCS to a more realistic propellant layout, with help from the ASTP doc and TM cross referencing:
1688336798440.png

So now DPO and DO both draw from the same source by default, with a backup tank available, where I've maintained the 3:1 ratio in quantity. Along with that come two (irreversible) KSU actions:
  • Backup mode, which cuts off supply from the main tanks and opens the supply valve on the backup tank - a swap of prop source for both DPO and DO. This is the expected action when fuel runs out;
  • Supply isolation, which blows the pyrovalve connecting both "sides", and opens the supply from the backup tank, which leaves DPO drawing from the main tanks, and DO from the backup tank only.
If for whatever reason they're combined, that effectively kills any DPO use and leaves only DO from the backup tank.
There's some really low hanging fruit with the pyrovalves on the DPO and DO supplies, but without any sort of failure simulation it basically amounts to pressing a button to turn on an indicator light.
Where this could get more interesting is introducing the pressurisation side, but I still have some reading up and asking around to do to understand how the two systems interact.
 

Urwumpe

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Actually this could be wrong. I would need to check the book, but I remember that the systems had been separate until the Soyuz T model for late Salyut and the unified propulsion system.
 

diogom

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The unification was SIO with the new SKD, right? So both RCS and main engine on the same fuel + oxidiser hypergolic sources. I'm still keeping the SKDU separate, as it always ran on hypergolics. From a quick check the book doesn't specify common or separate DPO/DO, and the ASTP report (2.5) never explicitly states it either, but implies common to me, especially here:
1688346458453.png

The accompanying schematic:
1688347197411.png

It's possible I didn't interpret it 100% right. Also likely can't take it entirely at face value, as it mentions SIO temperature is monitored in the KEI, which I think might be an error since every other source for the KEI mentions only pressures being monitored there for the engines, both for 7K-OK and Soyuz-TM. It also calls the ПКОТ an electrovalve, when from the П and function I'm pretty sure it's a pyrovalve. So some cross checking is needed. Though, Cutoff, as in normally open and where they are in the lines, does line up with a shared source, while the back up tank's output appears to be normally closed.

However, on the Tiapchenko source for supposedly 7K-OK I think I see what you mean. KSU column H does confuse me, as it's very different from the ASTP one. These would all be off-nominal commands: "Supply DPO/DO" I could see as being same as ASTP's backup pyrovalves, to feed each system on failure of an electrovalve (the bottom-most named valves on the schematic). But the two "DPO/DO pressure" do hint at separate sources. "DO tanks" is also odd, but assuming separate systems I could see it as "transfer DPO to the DO tanks" as part of DPO running out or having an issue. "DO nozzle" I don't even know. Could it be common DPO/DO was one of the changes made after Soyuz 11? Could even have been 7K-TM exclusive, as a stepping stone to -T's unified system.
 

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Actually I mean "Soyuz - A universal spacecraft", by Rex D. Hall and David J Shayler. :D

But it says little about the valves, only that the hydrogen peroxide is also used to drive the turbopump of the main engine (which the ASTP schematic does not show). The section about Cosmos 133 speaks a little more about the early Soyuz propellant system and the roles of the thrusters. It had a DPO failure right on spacecraft separation, and the DO can't stabilize the spacecraft during a longer main engine burn (which suggests the CoG was not in line with the thrust).

I would try to look at more information about Cosmos 133, since the accident probed exactly the valves and systems, that you are currently interested in.
 

diogom

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Actually I mean "Soyuz - A universal spacecraft", by Rex D. Hall and David J Shayler.
Yep, have that one too.

But it says little about the valves, only that the hydrogen peroxide is also used to drive the turbopump of the main engine (which the ASTP schematic does not show). The section about Cosmos 133 speaks a little more about the early Soyuz propellant system and the roles of the thrusters. It had a DPO failure right on spacecraft separation, and the DO can't stabilize the spacecraft during a longer main engine burn (which suggests the CoG was not in line with the thrust).

I would try to look at more information about Cosmos 133, since the accident probed exactly the valves and systems, that you are currently interested in.
Definitely right, in addition to the book, Chertok is also quite clear with the DPO and DO fuel distinction when describing that one. What's more, he also mentions a DO backup tank. Yeah, don't know what to make of this one honestly. I mean, unless I've been severely misinterpreting the weight of that report, my interpretation is still that 7K-TM had the common source by default, based on the text, schematics and KSU commands lining up. But for 7K-OK, separate seems clear. The KEI (Tiapchenko) also separates DPO and DO, with DO having two gas and two fuel tanks, supporting the backup DO tank mention above.
I believe 7K-TM, beyond what was needed for Apollo, was also a bit of a test bed for the next generation, though it seems it was mostly 7K-S which ended up becoming Soyuz-T. Maybe there was a change for this one specifically in the fuel system, though I'm not sure why have the intermediate arrangement. It's hard to tell what would have been true for 7K-T, since it's a bit of a mix of -OK and -TM. It seems the systems were separate as late as Soyuz 10, and there's not a lot about what was different after 11 besides the suits and panels. I might just default to separate sources. Plus backup DO.
 

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Might be dark in here for a month or two, but had some time a few weeks ago to work on something a bit different, so thought I'd leave an early look:

1693851230342.png
1693851241122.png

Didn't put that long into it, still needs tuning on size and fit at a later date, but thought it was a good first step in adding some more personality to the interior. The translation and rotation controls should logically follow, as they attach to the commander's seat and aren't too complex a shape anyway.
 

diogom

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Alright, back on this. This time, an old pain. So, rewinding to mid September, the launch of Soyuz MS-24 planted an idea which I've been avoiding thinking about too much until now so I didn't fall down the well, because the potential implications are interesting. Specifically, it was this burn schedule:

1700877241654.png

Thing is, I think I had somewhat misunderstood the sequence of events, or never given it much thought, since what is documented is Kurs and what isn't Kurs is mostly lost in time, but looking at the 1999 -TM manual, it's all there. And it might have been dumb to overlook.

I had this idea that the Hohmann would put the Soyuz immediately in the vicinity of the station. In fact, SB1 and SB2 are the Hohmann transfer, first to raise to the ISS's orbit, second to circularise, Delta-V and timing make that clear. But then the docking isn't for over an hour later, with the ISS 96 km away at SB2. So the Hohmann puts Soyuz at roughly 100 km, and then it coasts for roughly half an orbit until it enters the vicinity of the station and starts the final approach with SB3.

Why am I rambling about this? Key thing is the starting point for the final approach has a low relative velocity (compared to the 55 m/s of SB2, or in Salyut's case, 30ish m/s), with the circularisation taking place much earlier and being the burn that actually puts it on an intercept course. Would it be reasonable to assume that Igla approaches used this kind of profile too? I haven't been able to find much data one way or the other, but also haven't had the time to really look yet.

But essentially, the implication is: it might make my Igla implementation actually viable again. Because I was working on the potentially wrong assumption of a "straight in" approach with Igla handling 30+ m/s relative speeds, there was just too much energy for it to cancel while also controlling the approach and orientation. With a longer, slower, "shallower" approach, these are the conditions I was getting good results with in the beginning, before I started testing with Salyut at 350 km, or if one cancels the relative velocity manually a few km away, adds some speed towards the target, and activates Igla then.

So there are then two things need taken care of:
1 - need to scavenge for any historical rendezvous data that might exist. I know Chertok has some vague breadcrumbs, also wonder if Sven Grahn might have been able to get something. It feels too convenient regarding Igla, so I want to be as sure as I can. From what I've read at least, I've gotten the impression Igla was pretty sensitive to the starting conditions.

2 - if this is the way, well, there is a trade-off in flight complexity. Truth is I never got that technical with my Orbiter flying. So I'd have to figure out a proper procedure with the existing addon MFDs to set up such a trajectory, of which I only have limited experience with TransX (that was my attempt at a more professional version of the SyncMFD approach). Setting up a Hohmann transfer the end of which sets up the actual intercept, half an orbit later, in a reliable way, doesn't sound particularly out of reach, but I would be thankful for some starting pointers here, on which tool might be the best to accomplish this.
 

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1 - need to scavenge for any historical rendezvous data that might exist.
You could get the TLEs for the Soyuz flights but:
  • they might not have enough temporal detail to extract burn information
  • you'll need to request it from celestrak.org, as opposed to a "simple" download
 
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