Apollo 9 - P22 Day 7

[thermocalc]

Hi again to all,
going forward to day 7 with the 1st Landmark tracking exercise.
I did P51, I got the T alignment at 142:49:20, I did P52 Nominal -> so I am assuming that at 142:49:20 while in attitude 0-0-0 I should be LVLH Heads up with the SCT pointed to the Earth below.
the PAD I got was this:

If I am correct with the PAD interpretation, once entered in P22 the LMK coordinates the SCT points automatically to that landmark, at time T1 it should appear at the horizon, and at that time I should start the orbital rate, at time T2 the LMK is at 35 degree elevation and from there I should take the marks....am I right up to here?
but it not clear to me is "at what attitude"? 0-0-0 ? but that was supposed to be LVLH at time 142:49:20 .... T - Align PAD value ....
I saw that while still keeping 0-0-0 at time 143:18:04 from the SCT I was looking out into the stars, no Earth below....and more disturbing, at time 142:49:20 and at attitude 0-0-0 I was not LVLH "head up" but almost "+Normal" looking into Orbiter HUD ??? but before, when I did P51, P52 Nominal everything was looking good, all stars were there and no issues to realign the platform...why? did I make something wrong or my LMK Pad interpretation is wrong?

next thing, what is the meaning of the "70 NM South" information in the PAD? what I am suppose to do it?

thanks for any help.

Paolo.

 

[indy91]

If I am correct with the PAD interpretation, once entered in P22 the LMK coordinates the SCT points automatically to that landmark, at time T1 it should appear at the horizon, and at that time I should start the orbital rate, at time T2 the LMK is at 35 degree elevation and from there I should take the marks....am I right up to here?

You should be in orb rate a while before T1, at T1 you can start looking for the landmark, and you should start a pitch down maneuver at T2. I think you need about 0.5° per second in Earth orbit, 0.3°/s for lunar orbit.

but it not clear to me is "at what attitude"? 0-0-0 ? but that was supposed to be LVLH at time 142:49:20 .... T - Align PAD value ....
I saw that while still keeping 0-0-0 at time 143:18:04 from the SCT I was looking out into the stars, no Earth below....and more disturbing, at time 142:49:20 and at attitude 0-0-0 I was not LVLH "head up" but almost "+Normal" looking into Orbiter HUD ??? but before, when I did P51, P52 Nominal everything was looking good, all stars were there and no issues to realign the platform...why? did I make something wrong or my LMK Pad interpretation is wrong?

I think I have this from the flight plan or the mission techniques, but the T-Align is the same as sunrise time. So before sunrise you should maneuver to 0,0,0 IMU angles with V49. At sunrise you should start an orb rate maneuver, so you have the ORDEAL running and then keep 0° relative to the local horizon, so 0° on the ORDEAL driven FDAI. And you stay in that until T2 of the landmark.

next thing, what is the meaning of the "70 NM South" information in the PAD? what I am suppose to do it?

That is relative to the ground track of the CSM. So at the closest approach to the landmark, the landmark will be 70NM south of the CSM ground track.

 

[thermocalc]

thanks for nice explanations, now everything is clearer.
Just the ORDEAL part was not mentioned in the checklist and I didn't think about it.
Thanks Paolo

 

[thermocalc]

Hi to all, I tried as Indy suggested and everything worked well, and I found the ORDEAL initialization with V83 well before the time to do P22 but I didn't "conecting the dots" so to speak...so now everything make sense.
Anyway, I missed a lot the Earth Surface Markers to make a proper job ... ehehehehe....
hopefully one day one of you, GURUs developers, will make it working again (at least I keep hoping...)
all the best for now...