MCC timing and Incorrect/Missing DOI PAD

Sloppyphan

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Sorry I replied again in the previous Thread, but realized this should be in a new one.

Quote:
Originally Posted by indy91 View Post

40 minutes is pretty high, I've not seen more than 25 minutes on my tests. . As for the other time difference, it's probably something with the TLI targeting parameters for Apollo 10 we use. If it is something fixable in the TLI targeting then we will get 15 minutes back at least once it is fixed.
End Quote


So the TLI was maybe a little late but otherwise ok, My real issues start around the Pads needed right after LM undocking. Thats when they seem about 40 mins behind time line. I get an all Zero DOI pad, (or no pad just "thread started" ) then the abort and phasing p30 does show up eventually.
I tried to setup for phasing when the time came, but I have a feeling since their wasn't a DOI I didn't have everything setup right as the engine didn't fire.

I did have an issue with an MCC and LOI burn where the engine stopped early and I had to go direct to finish the burns and I am very sure I had done proper procedure, the first time it happened I even re-did it to see and same thing. I'm sure that could of affected the timeline also . .

My thought is I might had to start over which is a bummer
 

indy91

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The "thread started" with nothing after it usually means a calculations is failing, so there isn't really a chance to continue without fixing something. I checked an old scenario of mine and the DOI calculation still works in it. So I don't think it's a general problem.

Were your LOI-1 and LOI-2 also 40 minutes late already? It's not so much a problem of TLI being late, but the resulting trajectory from TLI being off somewhat that causes you to arrive late at the Moon. That's always going to be the case when the midcourse corrections are targeted for free return. How did your translunar phase go? Which MCCs did you have to do? MCC-1, 2, 3 and/or 4? And how large were they? If they were off because you got an early engine shutoff then maybe that caused even more delay in arriving at the Moon.

My current working theory for your DOI PAD issue is that something can't handle being so much off the timeline. Most of the timing in lunar orbit for PADs etc. is done relative to rev crossing (i.e. time since crossing 180° longitude of orbit e.g. 14). Maybe you can send me a pre DOI scenario and I can check if something can be done or fixed so that you don't need to refly half the mission.
 

Sloppyphan

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So as my primary focus had been to learn the LEM on this run, I admit I am guessing here a little . .

I believe LOI's were late but at the time it didn't seem this far behind expected, I believe I had mcc 2 &3, 3 and LOI-1 being the ones i think required a direct burn to finish probably not exact either . . But I'd need to go back into all my saves and rerun to confirm that.

The attached is post LOI's etc prior to activating the LEM
 

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  • Apollo 10 MCC -Day 5 LEM Startup.zip
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indy91

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Your lunar orbit timing isn't that far off I think, AOS time is pretty normal for what we have been getting, 20 minutes behind the flight plan or so. I'll fly more of the scenario as I haven't noticed any bigger issues so far. The only thing, which is a fairly bad one, is that you aren't aligned to the right REFSMMAT. It's quite far off. Maybe it's still the PTC REFSMMAT? Before MCC-4, if it gets scrubbed or not, there is an uplink that contains a preliminary landing site REFSMMAT. That should be followed by a P52 option 1. Maybe you didn't do the option 1 there? But that shouldn't cause bigger issues later on, only makes flight plan attitude not usable, so probably doesn't explain your DOI issue. I'll fly and see...
 

Sloppyphan

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Now that you mention the Pre landing ref I do recall not being able to do the 00001 option on the p52 I prob just moved on thinking I could/would get good #'s later from MCC.

This one is right prior to undocking when I should of had the doi but here it comes up as all zeros . .
 

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indy91

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The DOI calculation in that scenario is working for me. Which is my least favourite kind of issue, inconsistent...

But there is a bug that I suspect could cause this. I'll have that fixed soon. The calculation that is done as part of the DOI PAD involves planning the whole Apollo 10 rendezvous, so there is a lot that could potentially go wrong. So it might be one of the rendezvous calculations that I recently changed. I'll update you when I have a fixed version.
 

Sloppyphan

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In the Pre startup file (1st) or the pre undocking(2nd) file? I might run that again myself then just to see if I pass muster this time while waiting for update.
 

indy91

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In the Pre startup file (1st) or the pre undocking(2nd) file? I might run that again myself then just to see if I pass muster this time while waiting for update.

Pre undocking.
 

Sloppyphan

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Pre undocking.

I tried it a couple of times again and still no calc, just "Thread starting"

Though now I see it's only about 20 min behind for the DOI.

I would think this could occur again if I tried it in Apollo 11 also so is it best to wait for the update you had spoke of? My Primary purpose of doing 10 was just to learn the LEM so I was going to go back to 9 to get some more training.
 

indy91

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I actually did the update I was talking about and had just forgotten to say so in this thread. So it's still failing with the latest build? I can still not reproduce that, not even using your scenarios and I even fixed a bunch of only theoretical bugs...
 

Sloppyphan

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I actually did the update I was talking about and had just forgotten to say so in this thread. So it's still failing with the latest build? I can still not reproduce that, not even using your scenarios and I even fixed a bunch of only theoretical bugs...
SMH . . I think I didn't pull the most recent builds . . .I'll give it another try


Yes! The most recent one does work, Now lets see if I can fly the darn thing.
 
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