Wedge313
Well-known member
Hi again, I'm coming up on the Apollo 9 first SPS burn. Flight plan calls for a P52 Opt 1 alignment, followed by an alignment check. I'm not understanding something here....
I've copied the PAD, uplinked the target load and run P30. Then the PAMFD Checklist has us start P40 which displays F50 18 (which for me displayed my current RPY of 190,350,003. My PAD RPY is 000,356,001), then select P00.
Then the checklist leads me into P52 Opt 1. My new F 06 22 ICDU angles show the same as my current RPY. What REFSMMAT are we supposed to be aligning to ? I haven't uplinked a new REFSMMAT. The flight plan pg. 1-2 has a comment "The preferred IMU orientation for SPS No. 1 is calculated onboard, and the IMU is realigned to that orientation during the fourth night pass". When/how was I supposed to calculate that?
If I was doing my own RTCC, I think I would have uplinked a P30 REFSMMAT to do this burn. But I'm missing the preferred orientation. As a result when I V49 to the SPS-1 burn attitude my orientation is wrong, my SXTS check has me staring at the earth.
Please let me know what I'm doing wrong here. Thanks.
I've copied the PAD, uplinked the target load and run P30. Then the PAMFD Checklist has us start P40 which displays F50 18 (which for me displayed my current RPY of 190,350,003. My PAD RPY is 000,356,001), then select P00.
Then the checklist leads me into P52 Opt 1. My new F 06 22 ICDU angles show the same as my current RPY. What REFSMMAT are we supposed to be aligning to ? I haven't uplinked a new REFSMMAT. The flight plan pg. 1-2 has a comment "The preferred IMU orientation for SPS No. 1 is calculated onboard, and the IMU is realigned to that orientation during the fourth night pass". When/how was I supposed to calculate that?
If I was doing my own RTCC, I think I would have uplinked a P30 REFSMMAT to do this burn. But I'm missing the preferred orientation. As a result when I V49 to the SPS-1 burn attitude my orientation is wrong, my SXTS check has me staring at the earth.
Please let me know what I'm doing wrong here. Thanks.