For some reason I often get an alarm when I do Program 51. This happens when I have marked a star with V51. Despite this, it is fine to continue with the next star and V06N05 is still 00000. Why do I get the alarm? Is it the angle between the stars that affects whether I get the alarm or not? Or is the sc in the wrong direction some how?
P51 alarm
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What alarm? Call V05 N09 with the PROG ALARM light on to see.
I assume you're using NASSP v8?
I assume you're using NASSP v8?
rcflyinghokie
LM Junky
Yep V05 N09 will bring up the alarm code if you have a program alarm, there is also a list of codes in the G&C checklists as well.
Nah not required at all to zero between stars
This is strange but I'm obviously doing something fundamentally wrong. I am using apollo 9 NASSP v8. I have done a P51 with no problems and am now going to do a P52 Preferred orientation 00001 and then always get program alarm 405. The telescope cannot find the proposed star and is pointing at the completely wrong area with no star. If I do a REFSMMAT 00003 I have no problems at all. The telescope finds the stars without any problems. Any suggestions? There is something in the checklist if MGA (R3) should be less than +-70 degrees. Could this be where I am doing wrong?
rcflyinghokie
LM Junky
So I am trying to get this straight, you are doing the P51 after CMC/G&N powerup here? Did you maneuver your spacecraft to have a heads down/optics up attitude?
Also when you first run the P52 option 1, what is the MGA reported there? If that is beyond 70 from center you also need to maneuver first.
Hi rcflyinghokie and thanks for helping me! Yes, I'm doing the P51 after CMC/G&N powerup. No, I have not done a maneuver spacecraft to have a heads down/optics up attitude. Here I am very unsure of what I am expected to do. Please explain in detail what I am expected to do in relation to P51 and preferred 00001? I'm sure there's something here I don't quite understand. I send my scn file just before my P51 assignment.
rcflyinghokie
LM Junky
I'll check the save in a moment, but the 405 means it doesnt have a good set of stars in the optics field of view. Keep in mind you can physically find 2 stars and it still can give this error as the PICAPAR looks for stars within certain parameters wrt the optics.
EDIT: First thing I see is your optics are facing down to earth, you need to roll around 180 to point them to the stars
EDIT 2: I am seeing a lot of missed steps from the CMC/G&N powerup procedures, those would lead to a bad P51 and subsequently a bad P52.
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rcflyinghokie
LM Junky
Your optics are facing earth in the save you gave me. But as I said in my other edit, you have missed a few steps before P51, so you likely have a pad P51 orientation so the computer doesnt know which way the spacecraft is facing.
Yes, there is something here that I don't understand. Please explain in detail what I am expected to do. Where exactly should the spaceship aim and how do I know where to aim it? As you can see, I am not fully aware of the procedure.
rcflyinghokie
LM Junky
Well the checklist MFD has the procedures in order you were to follow for CMC and G&N powerup. After you do that you are to do a P51 marking 2 stars of your choice.
You were to do an uplink and a P30 and set the REFSMMAT with a 40E at the end of it, and then a P52 option 1.
Due to some issues with how you powered up, the IMU is throwing me 211/217, but marking 2 correct stars in P52 lets it torque back to where it should be.
You were to do an uplink and a P30 and set the REFSMMAT with a 40E at the end of it, and then a P52 option 1.
Due to some issues with how you powered up, the IMU is throwing me 211/217, but marking 2 correct stars in P52 lets it torque back to where it should be.
I'll check the save in a moment, but the 405 means it doesnt have a good set of stars in the optics field of view. Keep in mind you can physically find 2 stars and it still can give this error as the PICAPAR looks for stars within certain parameters wrt the optics.
EDIT: First thing I see is your optics are facing down to earth, you need to roll around 180 to point them to the stars
EDIT 2: I am seeing a lot of missed steps from the CMC/G&N powerup procedures, those would lead to a bad P51 and subsequently a bad P52.
40E? I have skipped that and gone straight to 37E 00E. Is this what I have done wrong? REFSMMAT with a 40E?
rcflyinghokie
LM Junky
Yeah it was part of the P30 procedure, by entering P40 during the F37 at the end of P30 then going to P00, you set your P30 REFSMMAT into the "desired" slot so it can be used by P52 option 1
rcflyinghokie
LM Junky
Checking back in, I was able to launch this save, redo the G&N powerup, and then do a P51/uplink/P30/P52. However due to the previous powerup issues I did get a 211/217 error when coarse aligning the IMU to the desired attitude, so the PICAPAR stars were off but I marked them and it just torqued the platform a bit more and fixed it.
rcflyinghokie
LM Junky
Oh yes saving often is invaluable!Do again do right! Thank you for your invaluable help. I'll go back and redo. That is the advantage of many save
Just for information. This time everything worked as it should but I'm not quite sure why. I think I don't fully understand what is going on under p51 and p52. And I'm not sure what happens with the different choices PREF, NOM and REFMMAT. Anyone able to explain or give me something to read easily?
. I think I don't fully understand what is going on under p51 and p52. And I'm not sure what happens with the different choices PREF, NOM and REFMMAT. Anyone able to explain or give me something to read easily?
rcflyinghokie
LM Junky
Sure, so P51 is imu orientation. It allows the computer to orient itself based on the current state of the platform and the stars. Essentially this provides the initial reference to the stars.Just for information. This time everything worked as it should but I'm not quite sure why
P52 is what actually aligns the platform to a REFSMMAT (REFerence to Stable Member MATrix).
Option 1 will move the platform to a "desired" orientation, such as a P30 REFSMMAT set on board or an uplinked REFSMMAT.
Option 2 sets a "nominal" REFSMMAT, setting a LVLH orientation (wings level) for a given time in the orbit.
Option 3 is used to adjust for drift and "fine tune" the platform without making any changes to the REFSMMAT.
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