[NASSP 8][Apollo 7] Realtime simulation attempt preparation

STS

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Dear all,

On the coming up month of november I will embark again on a real time simulation adventure, this time with Apollo 7. I feel more and more comfortable with the rendezvous, wich I think is the most challenging part of the mission, but I have a few thoughts or questions that I would like to share with you before I launch.
  • P23: Is it possible to be completed on LEO, and with the Apollo 7 (8) software? I understood that the crew had a lot of trouble with it and even they could not complete the tests for P23, if I understood the mission report correctly: https://www.hq.nasa.gov/alsj/a410/A07_MissionReport.pdf . Also I encountered problems when practising it on NASSP 8.
  • Using VC: I understand that the VC is not supported at this moment, as it is not completed. During test runs of parts of Apollo 7 I encontered some issues (indicators not properly 'calibrated', and unknown switches being triggered when using right mouse button to move the view [seems like there are some clickspots not correctly mapped, but don´t know exactly where, so I couldn´t report them]) so: do you recommend me to use the VC for this mission or I should use the supported 2D panels? What is the worst that could happen when using the VC?
  • About rendezvous and T&D demo: Did the crew perform a flyaround on the S-IVB or just stayed on keepstation when the rendezvous or the T&D demo finished? About the T&D I know that they couldn´t get very close to the S-IVB because a panel failed to deploy fully, but I don´t know if they intended to get very close to the S-IVB as to simulate a docking.
  • How about recovering the Post-Splashdown Egress? Could we have it on a update by november? (https://www.orbiter-forum.com/threads/nassp-7-crew-egress-on-splashdown.39787/)
Best regards,
 

indy91

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Dear all,

On the coming up month of november I will embark again on a real time simulation adventure, this time with Apollo 7. I feel more and more comfortable with the rendezvous, wich I think is the most challenging part of the mission, but I have a few thoughts or questions that I would like to share with you before I launch.

I will make sure to prioritize updates that will make Apollo 7 more stable!

  • P23: Is it possible to be completed on LEO, and with the Apollo 7 (8) software? I understood that the crew had a lot of trouble with it and even they could not complete the tests for P23, if I understood the mission report correctly: https://www.hq.nasa.gov/alsj/a410/A07_MissionReport.pdf . Also I encountered problems when practising it on NASSP 8.

It's as you say, it doesn't really work properly in Earth orbit. They tried it, you can try it if you want, but you will never get good results.

  • Using VC: I understand that the VC is not supported at this moment, as it is not completed. During test runs of parts of Apollo 7 I encontered some issues (indicators not properly 'calibrated', and unknown switches being triggered when using right mouse button to move the view [seems like there are some clickspots not correctly mapped, but don´t know exactly where, so I couldn´t report them]) so: do you recommend me to use the VC for this mission or I should use the supported 2D panels? What is the worst that could happen when using the VC?

jalexb88 will know more about that, but I think nothing bad will happen from using the VC. It's a bit buggy, some clickspots are difficult to use, but it's mostly workable. I'm still finding myself using the 2D panel more, at least in the CSM. But with the VC getting better over time I am sure I will slowly transition.

  • About rendezvous and T&D demo: Did the crew perform a flyaround on the S-IVB or just stayed on keepstation when the rendezvous or the T&D demo finished? About the T&D I know that they couldn´t get very close to the S-IVB because a panel failed to deploy fully, but I don´t know if they intended to get very close to the S-IVB as to simulate a docking.

I don't think they ever did a flyaround. The final flight plan (which has recently become available: https://www.ibiblio.org/apollo/Documents/apollo7_final_flight_plan.pdf) doesn't go into details of how close they wanted to fly to the S-IVB, so not really sure about that.


Yep, I can take a look at that soon. I'll write in the V8 release thread once it's available. It's probably going to be a button in the PAMFD.
 

STS

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Hello,

I am practising P22 from this scenario:

Apollo 7 - 12 - Before Landmark Tracking T+122h.scn

But on that scenario I found the following issues:
  • Mission Timer is not started
  • RCS are not working. (I tried the RCS CMD switch and RCS Transfer to SM, even the SEQS to ON)
Can you check it?

Best regards.
 

indy91

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Yeah, the old Apollo 7 and 8 mission scenarios are still mostly the scenarios released with NASSP 7. Mission Timer scenario saving format has changed, so that got broken. The RCS Enable relays were moved to their correct system which at some point (years ago) broke Auto RCS in old scenarios. You have to enable those relays again by pushing in the four SECS circuit breakers and then RCS Cmd - On and RCS Transfer - SM. Those old scenarios haven't been fully replaced yet, because they aren't technically completely broken. You just have to fix the mission timers and the Auto RCS manually.
 
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STS

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Yeah, the old Apollo 7 and 8 mission scenarios are still mostly the scenarios released with NASSP 7. Mission Timer scenario saving format has changed, so that got broken. The RCS Enable relays were moved to their correct system which at some point (years ago) broke Auto RCS in old scenarios. You have to enable those relays again by pushing in the four SECS circuit breakers and then RCS Cmd - On and RCS Transfer - SM. Those old scenarios haven't been fully replaced yet, because they aren't technically completely broken. You just have to fix the mission timers and the Auto RCS manually.
Could you clarify the panels for the breakers? 8 and...?
 

indy91

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The four SECS breakers on panel 8, and then RCS Cmd - On and RCS TRNFR - SM on panel 2. Actually only one of these two switches is required, I think, but I forgot which haha.
 

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Actually the only cb that has to be (temporarily!) closed out of the ordinary is the SECS ARM A BAT A cb, because it powers the RCS-CMD switch. The RCS TRNFR switch is powered by the RCS LOGIC cbs. Those are normally closed. Well, at least in the missions we simulate right now. Somewhere down the line the regimen regarding them changed and they were opened after CSM/LV sep.
 

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@STS, to give you a big more confidence in this mission, I wanted to let you know two things. 1) about a month ago, I finished a full flythrough of Apollo 7 from the -4h prelaunch, all the way to splashdown, without issue. 2) I'm going to be out of town for a few days, so I'm planning to leave an Apollo 7 scenario running in real-time, for approximately 90 hours, obviously I won't be able to interact with the simulation, but it will be a good test of the stability of the simulation (which I already have high confidence in).
 
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STS

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Dear all,

I have two more questions, regarding passing data to the update forms:
  • How to read LVPD? from the following picture, how would you write that on the update form? I guess 5 Oxid, and 5 Fuel... (Taken at T+30 minutes)
1633450144435.png

  • On my LibreOffice Writer, the Update Forms document looks broken. Is it designed to be viewed with Microsoft Word, or it got broken with some LibreOffice update?

1633450224678.png
1633450258738.png


1633450300280.png


Best regards!
 

indy91

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The word document looks fine to me in Microsoft Word, so must be a Libre Office issue. I guess those Word documents haven't been updated since NASSP 7. We will probably have this kind of document for every mission that NASSP 8 supports (Apollo 7-11), as close as possible to the actual checklists. So it might change for Apollo 7 at some point with update documentation as-flown.

For the Gimbal Position/Fuel Pressure Indicator (GP/FPI) it's of course dual use and the second scale is for the SPS trim gimbal angles (-4.5 to +4.5). The fuel/oxidizer pressure scale would be pressure in PSI, but we actually have that wrong in NASSP. It shows percentage of propellant left, scaled to the 0 to 50 psi. That is the oxidier "pressure" and for fuel is has a small offset to oxidier, maybe just to make it look different? No idea, but this is something that should be changed, but I think there isn't really a point to changing it until we actually simulate those fuel and oxidizer pressures dynamically.
 
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STS

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Dear all,

For some SPS burns, ullage is required to be performed with 2 +X jets.

I don´t know how to select 2 +X jets. It is done via the Panel 8 or on V48?

Best regards.
 

indy91

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If it's an SCS burn then I think the only way to do it is with the Auto RCS switch on panel 8. But with the CMC you can use V48. The 2nd and 3rd digit of R1 in V46 is:

-Quad A/C for +X (0 = Fail A/C, 1 = Use A/C)
-Quad B/D for +X (0 = Fail B/D, 1 = Use B/D)

So setting either one of these digits to a 0 and the other to a 1 will get you a 2 jet ullage.
 
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STS

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Dear all,

On the flightplan (Doc\Project Apollo - NASSP\Flightplans\Apollo 7\Apollo 7 Flight Plan.doc) there is a section called Maneuver Planning. There, the burns for the mission are described, showing information about ullage time, number of jets for ullage, and a column that I don´t understand very well. DV A/B. For some burns it shows A+B, A, B or blank. I understand that it is the switch setting at TIG -2 minutes, as follows:

  • A+B: Both switches on at T-2 minutes.
  • A: Switch A on at T -2 minutes, and burn will be done with only this switch (valve) on (opened).
  • B: Switch B on at T -2 minutes, and burn will be done with only this switch (valve) on (opened).
Where I have the question is when it shows blank (7th and 8th burn). Does blank mean that it is per the nominal checklist? (A on at T-2 minutes and B on at T+3 seconds)

Best regards.
 

indy91

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I would have to check in the transcript, but I think they didn't adopt the practice of starting the SPS with only one set of valves until after Apollo 7, based on the flight experience. When you start the engine with both open then you get an overpressure transient at ignition, which isn't desirable and also not so predictable. So I think they used both sets of valves for SPS-7 and 8. In NASSP it only makes a difference for short burns, as the thrust rise at ignition and the tailoff after cutoff is slightly different between the two configurations. Once you have switched on the second set of valves at T+3 seconds there is no difference anymore. And SPS-7 and 8 are longer than 3 seconds.


So this might be relevant for your full mission attempt. A while ago I started a development branch to implement realistic drag behavior for all orbital vehicles, as right now that is a mixture of too low and quite random. But that project had morphed into a much bigger, general Apollo 7 and Saturn IB update. But because it was such a big, complicated project it hasn't been merged into the Orbiter2016 releases yet. What is relevant for you is that I am right now working on doing a smaller update with parts of that branch and that will be getting released some time in the next few days.

Here are the updates that will come:

-LVDC orbital navigation includes drag calculations (but with very reduced drag force for now, as there isn't much drag yet)
-Saturn IB S-IVB only had about 1/5 the amount of APS propellant for attitude control as a Saturn V S-IVB had. Right now both versions have the same, larger amount.
-CSM + Saturn IB S-IVB stage (before LV sep) has a wrong center of gravity. It's at the place where the S-IVB alone would have the CG, very close to the APS modules, so in pitch and yaw the APS needs to spend a lot of propellant. Fixing this and the reduced propellant probably cancel each other out in terms of consumption.

I will of course test these changes, but they do affect Apollo 7 a lot and there is always the potential for bugs, so if you want to stay on the safe side for your full mission you might not want to update your NASSP install any more.

What will take longer until a release is these updates I was working on:

-Realistic aerodynamics for CSM, LM and S-IVB
-Various Apollo 7 MCC updates, some related to drag (like the second phasing maneuver calculation, taking into account the different drag forces for CSM vs. S-IVB)

The MCC changes I made will be breaking old scenarios. I had hoped to have these updates ready sooner, but they will not be merged before I haven't test flown the whole mission and updated all the scenarios.
 
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STS

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Dear Houston, again, I think this would be the last questions before I head to the cape for launch.
  • Do you have the GET´s for the TV transmissions? Are those easy to find on the transcripts? I would like to make some surprises :)
  • I have a question regarding manual P27 update, but I will post it later.
Best regards,
 

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I'm pretty sure TV transmissions are part of the flight plan.
What do you wanna know about P27? I'm sure I can help you out.
 
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