Problem Couple of problems with NASSP

Radar_Contact

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Hello,
I'm a bit frustrated, because after installing beta (o2016 and nassp beta) I started to have problems with NASSP. Before beta I did like 7 hours of apollo 7 mission without problems, mostly using only a checklist. Now, the first problems start at T+0:30:00.

1. When using time warp (limited to x50, as said in installation guide) vessel just revolves around its own axis
2. This is what I got after I entered V82E and then PRO. Perigee -06609? Ship was in stable orbit, I checked it in def o2016 mfd
1648057988172.png


3. Problems with P52. CMC doesn't work and doesn't get automatically focused on a selected star. DSKY doesn't display F 50 25 R1 00014 after the procedure. Also during the whole procedure, PGNS and PROG lights are on. And finally, this is the SCT/SXT angle I get after selecting two stars manually:
1648058233403.png


4. RCS controls doesn't work after completing the checklist steps.

How to fix it? What I'm doing wrong?
 
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indy91

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1. When using time warp (limited to x50, as said in installation guide) vessel just revolves around its own axis

That is probably caused by RCS firing. Time acceleration doesn't go well together with any vehicle trying to fire thrusters. When you are still attached to the S-IVB then the S-IVB will perform the attitude control. With that you can safely use 10x, but I don't think more. After getting away from the S-IVB and when RCS isn't trying to fire in attitude hold or so you can use more.

For the other issues, can you post a scenario from on orbit? You did have P11 running during launch, right?
 

Radar_Contact

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That is probably caused by RCS firing. Time acceleration doesn't go well together with any vehicle trying to fire thrusters. When you are still attached to the S-IVB then the S-IVB will perform the attitude control. With that you can safely use 10x, but I don't think more. After getting away from the S-IVB and when RCS isn't trying to fire in attitude hold or so you can use more.
Thanks, good to know.
For the other issues, can you post a scenario from on orbit? You did have P11 running during launch, right?
Sure, and yes, I did have P11 running.
 

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indy91

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Ok the CMC state vector is indeed bad somehow. No idea why yet, but the uplink later would fix that. You did let it uplink the state vector at T+56min, right? That could tie into the next issue.

Problems with P52. CMC doesn't work and doesn't get automatically focused on a selected star. DSKY doesn't display F 50 25 R1 00014 after the procedure. Also during the whole procedure, PGNS and PROG lights are on. And finally, this is the SCT/SXT angle I get after selecting two stars manually:

The CMC checks if the Earth is in the way of stars or if the star is within 5° of the horizon. And if that is so it doesn't want to use the star for P52. So if the state vector is wrong, but also if you are just unlucky with timing, then P52 doesn't find two good stars that are within the range of the sextant at your current attitude (and isn't occulted by the Earth). It then gives you a program alarm which you can check with V05 N09. If that says 405 then P52 didn't find two stars. What you then have to do is V32E to go back to the option code 00015. Also RSET to get rid of the alarm lights. You can then either wait and PRO again (maybe it was just bad timing and it will then work) or if you weren't still attached to the S-IVB you could change the attitude. Or you press ENTR instead of PRO and choose two stars manually.

When I tried the P52 (with the state vector fixed per the scheduled uplink) in your scenario then I also got that program alarm. But I selected two stars manually and I got a perfect result. IMU alignment was good even before the P52 and I got small torquing angles.

So after P52 throws that alarm you must have done something not quite correct. Normally after the P52 is done (after the star angle difference is shown) it will gyro torque the IMU to the new attitude. With P52 option 3 this is usually a tiny angle and happens quite fast. But if the attitude difference is large, which was probably the case for you judging by that star angle difference, then that can take quite a while. During this time the DSKY is blank, so that's probably why the 00014 didn't show up. It was still torquing the IMU to the new (and wrong) attitude.

I can also check the prelaunch scenario you were using if it wasn't the T-60s scenario that comes with NASSP. Maybe I can do a launch with it and figure out what happened to your state vector.
 

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You did let it uplink the state vector at T+56min, right? That could tie into the next issue.
Yes. And the P52 was after that uplink. I've done P52 many times and never had this problems. This time I did the same as before. And yeah it will be good if you check that scenario, it was "Apollo 7 launch".
 

indy91

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Yes. And the P52 was after that uplink. I've done P52 many times and never had this problems. This time I did the same as before. And yeah it will be good if you check that scenario, it was "Apollo 7 launch".

As I said getting that 405 program alarm in P52 can be quite normal even if you did nothing wrong, just some bad luck with star availability at the time. Aside from the state vector being off I can't seen anything wrong in the scenario you posted. P52 works as expected.

"Apollo 7 launch", do you mean the scenario that comes with NASSP? That is not really what I meant when I asked for the scenario you used to launch. Unless you never saved and loaded before launch, then I will check if this same issue happens using that T-4h scenario (instead of the T-60s scenario). But if you loaded a later scenario you had saved before launch and that gave you the problem I could check what could be wrong with the CMC there that causes the state vector problem.
 

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Ah ok, sorry. Here is the scenario.
 

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rcflyinghokie

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Hmm there is a LOX dump and P47 before the P52 time you are performing. Did you use time accel during that or fail to run P47 during the dump by chance?

EDIT: So I just flew your scn up to the P52 point and had no issues. I am still suspecting you ended up with a bad state vector due to time acceleration, not using a P47 during the LOX dump, or both.

EDIT2: Looks like your other save was a bad SV before the LOX dump, so disregard that theory. I wonder if this is tied into your rates issue you had before due to a botched install. Can you replicate it from your launch scn again?
 
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I made a scenario again, from the launch to T+2:15:00 without using time acceleration, and again something is not ok with the P52 - PGNS and PROG lights. Need to select star manually. SCT/SXT Angle +041.74.
 

indy91

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I made a scenario again, from the launch to T+2:15:00 without using time acceleration, and again something is not ok with the P52 - PGNS and PROG lights. Need to select star manually. SCT/SXT Angle +041.74.

How is the state vector after insertion this time? V82 showing goods things?

I am pretty sure you are doing something not quite correct after getting the 405 program alarm, because in your T+38min scenario P52 worked perfectly fine. So let's take it step by step. You are getting to the step in P52 where it shows F 50 25, 00015. On that display you have the option to let the CMC pick a pair of stars (by pressing PRO) or to manually select two stars (pressing ENTR). Normally you do PRO. You then get the PROG light and it shows F 05 09, 00405 correct? The 405 program alarm means it didn't find a good pair of stars. That can be due to a bad state vector or unfortunate timing and/or attitude. On that display you have two options. Either PRO which will get you to F 01 70 to manually select a star. Or V32E which gets you back to F 50 25, 00015. You could then wait for a minute or two and press PRO again, maybe it now finds two stars automatically.

When you manually select stars it will show you N70 before you take the mark and N71 after you take the mark. And that will happen twice, for each of the two stars. In each case you can change the number it displays in N70 or N71, so if you have marked on a different star than selected in N70 you can still change it in N71. So maybe you entered the second star into the first N71 or something like that? That could explain the large star angle error. Otherwise I can only think of the optics maybe not being correctly zeroed or so.
 

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You then get the PROG light and it shows F 05 09, 00405 correct?
Nah, I don't get any 405 program alarm. It just normally shows a star to select. I can record a quick vid how I do this so you can tell me what I'm doing wrong or something.
 

indy91

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A video might help yeah. But you did say you are getting a program alarm (PROG light goes on) at some point. When you check V05 N09, what is the alarm code? And at what point in the procedure do you get the alarm?
 

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Okay, so I tried to do P52 one more time, and I had no problems at all. And I think what I possibly did wrong, may be stupid, but I left the "opt zero" switch at zero position. And that's because I wrongly understood the checklist - OPT ZERO - OFF (15 SEC). I thought I need to switch it to OFF for 15 sec and then go back to ZERO. So I had problems only because of timewarp xD So thanks for the help, at least I know more about P52.
 

indy91

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Yeah the optics zero switch can catch you out. After a period of having optics powered off you also need to cycle the switch from zero to off to zero so that the CMC knows that it's being zeroed. And it is possible (but unlikely) that the real position of the optics (shaft and trunnion angles) and the CMC's knowledge of the position are getting desynced. So it's always good to do optics zeroing before a P52. And then to off of course. Did you figure out which program alarm you were getting? Maybe that you didn't have the zero switch in the zero position for long enough?

But how were you even able to manually control the optics and place the sextant on the stars if you had the optics in zero mode?
 

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Did you figure out which program alarm you were getting? Maybe that you didn't have the zero switch in the zero position for long enough?
Nope, and yes it is possible that it wasn't at zero for long enough.
But how were you even able to manually control the optics and place the sextant on the stars if you had the optics in zero mode?
?‍♂️
 
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