CSI? CDH? TPI? Help please?

Max-Q

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I am working through the Apollo 11 flight with MCC, and it has gone fairly well up until rendezvous.
Before liftoff, I get "LM ASCENT" and "P32 CSI UPDATE" PADs from MCC.
Lunar liftoff and ascent are nominal, then the checklist begins steps for "CSI". I have succeeded in doing a (CSI?) maneuver that is HOPEFULLY correct.
After that, things get really crazy. First, in P33, I am not sure what data to enter... Throw in frequent random program alarms, and P33 not working like the checklist says it should, and I am thoroughly confused.
First, P33 wants the TIG for a Plane Change maneuver, and when I enter it, the countdown clock in R2 shows... not a countdown to the TIG I entered, but to what I think is CDH!
Oh, and what the heck are CSI and CDH anyway?
To sum it all up, I AM THOUROUGHLY CONFUSED!

I am not a newbie to NASSP, I have successfully completed Apollo 8 previously, and studied a lot of detail on the Apollo program.

Sorry if this is hard to follow, I just joined here a few days ago.
 

Thespacer

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Max-Q

I think most people agree rendezvous is daunting. So perhaps a few general resources to help you get started:

I found this old video helpful to describe the process (eg what is CSI, CDH etc):

This site also breaks it down well: https://history.nasa.gov/afj/loressay.html

A recent thread a few folks here participated in on this topic also may help:
Thread 'Ascent advice'
https://www.orbiter-forum.com/threads/ascent-advice.39653/

If you have a program alarm, hit V05 N09 and it will give you the alarm code. That might also help identify if you have some other issues going on that are affecting progress.
Hope that helps.
 

MrFickles

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Don't worry! I'm sure everyone had trouble flying the LM after getting used to the CSM. That's an excellent video that tells you what each maneuver (CSI, CDH, TPI) aims to accomplish during the rendezvous sequence.

The whole rendezvous sequence depends on where and when the intercept will take place, which is around orbital sunrise on the 3rd orbit (2nd on Apollo 14 onwards, skipping CSI and CDH). This will determine the TIG of TPI, which in turn will determine the TIG and dV for every other burn (that's why P32 asks for TPI parameters).

When you first enter P33, the time you see on F06 13 is the TIG of CDH that the LGC has calculated when you were running through P32. You can either use the calculated TIG or use the MCC calculated TIG sent on CDH PAD if they are reasonably close to each other. When both spacecraft are reasonably in-plane, which is normally the case, the plane change is incorporated into the CSI, and CDH burns. Notice how your time of plane change is the same as CDH TIG and it counts down to CDH.

This document (P32-P35 on pages 29-33) lists what the LGC wants from you and what it's trying to tell you.
 
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Max-Q

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At last, success! That video was very helpful!
Thank you so much for saving my mission!!!

or use the MCC calculated TIG sent on CDH PAD
I never got a CDH pad! Only "LM ASCENT" and "P32 CSI UPDATE".

However, I now have a much smaller issue. In the checklist for LM Jett, I am instructed to load RPY angles for jett attitude in the DAP. Where do I get this attitude?
 

rcflyinghokie13

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At last, success! That video was very helpful!
Thank you so much for saving my mission!!!


I never got a CDH pad! Only "LM ASCENT" and "P32 CSI UPDATE".

However, I now have a much smaller issue. In the checklist for LM Jett, I am instructed to load RPY angles for jett attitude in the DAP. Where do I get this attitude?
You wont get a CDH or TPI pad.

Regarding the jettison attitude, they were read up by MCCH and in the flight plan. I cannot remember if one of the pads in the NASSP MCC displays it I will check on that.

In the mean time, the jettison attitude was CSM R000 P025 Y000. I will probably add this to the checklist.
 

rcflyinghokie13

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Good! I though my NASSP install was messed up!

So far, no LM jett pad.
Yeah if it is there it would be a remark of some sort. But I added it to the checklist MFD anyways it should get merged in there today.
 

Max-Q

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Thanks for all the help! RPY 000 025 000 for LM Jett, and Apollo 11 is go TEI!
 
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