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rcflyinghokie

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That is exactly what I am doing now.

At GET 5h 23m the Apollo 12 flightplan tells me to uplink my PTC REFSMMAT. I think I have found the REFSMMAT Uplink screen in RTCC and calculated my PTC REFSMMAT, but I cannot figure out how to uplink it to the CMC.
Utilities->REFSMMAT->OPT until you see PTC then CLC
Uplinks->DISPLAY->12 CMC REFSMMAT Update->CLC->2 DESIRED->UPLINK
 

rcflyinghokie

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Ok, done. Uplink, P52, and GDC align all went well. Is there any way to confirm my REFSMMAT is correct?
Well assuming you used the PTC REFSMMAT and ran a P52 Opt 1 it should be good.

One sanity check though is when you maneuver to PTC attitude, your spacecraft stack is practically perpendicular to the sun.
 

indy91

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Now a little later in the flightplan, what does LOAD W MATRIX (R1+80000)(R2+00070) mean?

That is initializing the W-Matrix (basically a Kalman filter) for P23. Basically an initial error, in this case 80,000 feet and 7.0 ft/s. And with each mark in P23 that error should in theory go down.

Seems like the flight plan doesn't give the full procedure, but what you have to do there is:

V67E (Extended verb for W-Matrix display and changing the re-initialization parameters)
+80000E
+00070E
+00003E (3 for P23, there is also 1 for P20 and 2 for P22).
 

Max-Q

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How do I determine if MCC-1 is needed? If it is, how do I calculate it, uplink it, and get my PAD?
I assume all of the other MCCs are done the same way?
 

rcflyinghokie

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How do I determine if MCC-1 is needed? If it is, how do I calculate it, uplink it, and get my PAD?
I assume all of the other MCCs are done the same way?
So a lot of this stems from learning the mission rules. There are parameters on computing the burns at the MCC times and when to burn or to postpone etc.

IIRC MCC2 and 4 are the preferred points. The RTCC manual has the flows for these computations as well.
 

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I followed the steps in the RTCC manual for midcourse planning, using option 5 as specified in the RTCC MFD Input Reference Guide for Apollo 12 MCC-1.
When I calculate the maneuver, I get a huge MCC of dV 1923.5
Where did I go wrong?
 

rcflyinghokie

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I followed the steps in the RTCC manual for midcourse planning, using option 5 as specified in the RTCC MFD Input Reference Guide for Apollo 12 MCC-1.
When I calculate the maneuver, I get a huge MCC of dV 1923.5
Where did I go wrong?
Its hard to say without seeing exactly what you are doing to be honest. As I said, feel free to pop over to the discord which makes this a lot easier...otherwise you can post your scn here and I can take a look.
 

indy91

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This doesn't look like TLI went well. The eccentricity of the orbit is too low, the apoapsis is only halfway to the Moon. Not sure what could have gone wrong though. Did you manually cut off? Maybe some recent LVDC update broke Apollo 12 only, do you have a scenario from before timebase 6 starts (when the S-II sep light goes on before TLI)?
 

Max-Q

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Yeah, I was pretty suspicious of TLI. The EMS still showed quite a bit of dV left at cutoff...
No, I didn't shut down manually, the burn time was within about 1 second of the expected time.
Here is a scenario from before TB6 as well as my TLI PAD.
 

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indy91

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I've just done a flawless TLI with that scenario. Very close to free return and MCC-2 would have about the same DV as the flight plan.

Your pre MCC-1 scenario presents a bunch of clues what could have happened, in the LVDC variables. My conclusion is that up to 7-8 seconds before cutoff everything went normal. The LVDC went into terminal guidance at 15 seconds before cutoff. But it never went into the attitude hold mode for the last 3 seconds of the burn. The last time-to-go until cutoff the LVDC had is 7 seconds. The cutoff was not caused by the LVDC with a velocity cutoff (nominal method) and it also wasn't caused by the S-II/S-IVB staging switch or a cutof signal from the CMC.

So the only things left I could imagine is a manual cutoff with the EDS or the Orbiter method. The THC can be used to shut off the engine like an abort. And what sadly hasn't been disabled yet is the plus and minus keys on the numpad. They work like for all other vehicles in Orbiter, + gives you full thrust, - cuts off the engine. I've tested it and I can generate about the same conditions in the LVDC as in your pre MCC-1 scenario by using the minus key a few seconds before cutoff. So maybe you accidentally hit the minus key?

In either case, I think you should just try that pre TLI scenario again. If everything works fine (EMS went to -80 for me, that is a good sign) then you can just continue. If the same issue happens again, maybe the LVDC log has some clues. So after TLI fails again (if it fails) please post the file "lvlog.txt" here so that I can take a look. That file in the main Orbiter folder.
 

Max-Q

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I am quite sure I did not touch anything!
However, the throttle control on my joystick is kinda noisy, so that might have had something to do with it…
I will re-try TLI with this scenario and report back later.
 

n72.75

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I am quite sure I did not touch anything!
However, the throttle control on my joystick is kinda noisy, so that might have had something to do with it…
I will re-try TLI with this scenario and report back later.
Noisy analog controllers have caused problems for people in the past. The most recent example I can think of was one causing rotations. If you have access to deadband settings, I recommend you adjust those, but either way, we should disable the default orbiter controls.
 

Max-Q

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Yeah, probably should disable that!
Anyway, I gave TLI a second go, and it seems much better. My EMS went to -79.1
Now MCC1 dV is 56.3 f/s. That sounds a bit high, but I am OK with it.
 

rcflyinghokie

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Yeah, probably should disable that!
Anyway, I gave TLI a second go, and it seems much better. My EMS went to -79.1
Now MCC1 dV is 56.3 f/s. That sounds a bit high, but I am OK with it.
That EMS seems pretty high

EDIT was referring to both EMS values, not MCC dV
 
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