p37, attitude RPY information?

[Sverige]

I'm working on Apollo 8 and I'm on return to earth. I have a question related to p37. At 06 81 I get calculated Dv for xyz (LV) but it is unclear to me where do I get burn attitude RPY? p37 assumes that contact with the ground is unavailable (no PAD) so I wonder where I get the burn attitude RPY information? I guess I've missed something really fundamental in p37 but I'm lost. Grateful for all the help I can get.

:tiphat: Mikael

 

[indy91]

The only way of knowing the burn attitude is to call P40 or P41 after the P37. And then let it auto maneuver to the burn attitude, or write down the N18 angles or so. That's the same as for a ground calculated maneuver, except that you usually maneuver with V49 to the burn attitude before calling P40. In that case the auto maneuver in P40 is just a very small trim of the attitude, as you are already within a degree of the desired attitude.

The Maneuver PAD roll angle usually has a specific value, either to have the CSM heads up or down. In the no comm case that isn't the case, as P40 just calculates the shortest attitude maneuver to the desired burn direction (not attitude). You could still let it auto maneuver to the burn attitude (PRO on the 50 18) and once you are there manually adjust the roll angle as desired. And then PRO on the 50 18 again for the final trim.

 

[Sverige]

Thanks!

/Mikael