Question Apollo 12 evasive maneuver

[riclourenco]

Hello!

I am trying to do Apollo 12 using Apollo RTCC MFD. I was able to do the TLI very well. Now I'm at GET + - 4h, and it's time to enter the PAD evasive maneuver data on the AGC. I can't find any options for this in RTCC MFD. I tried to get this PAD from Pre-advisory data> Maneuver Pad> P30 maneuver, but I find no option to create an evasive maneuver.

https://puu.sh/ECVQM/3fd206ce4a.png

Can you help me? Is there anything that guides us with RTCC MFD throughout the missions that dont have MCC?

Thank you.

 

[indy91]

Hello!

I am trying to do Apollo 12 using Apollo RTCC MFD. I was able to do the TLI very well. Now I'm at GET + - 4h, and it's time to enter the PAD evasive maneuver data on the AGC. I can't find any options for this in RTCC MFD. I tried to get this PAD from Pre-advisory data> Maneuver Pad> P30 maneuver, but I find no option to create an evasive maneuver.

https://puu.sh/ECVQM/3fd206ce4a.png

Can you help me?

You would enter the evasive maneuver data with the TIG and DV buttons on the Maneuver PAD page, as the evasive maneuver had predetermined TIG and DV. So there wasn't any calculation done for it. Except maybe the TIG, it would be at a specific time after TLI, not a specific time after liftoff I think.

But actually on Apollo 12 the only evasive maneuver was done by the separated S-IVB. This can be done in NASSP as well, by sending commands to the S-IVB with the PAMFD, on the IU page. You need to enter the name of the S-IVB there (AS-507-S4BSTG I think) and then send the commands "Timebase 8 Enable" and "Evasive Maneuver Enable".

Is there anything that guides us with RTCC MFD throughout the missions that dont have MCC?

There is an outdated manual under Doc\Project Apollo - NASSP\Programmers Notes. I am in the middle of another big RTCC MFD update, when that is done I probably have a clearer picture of how the MFD will look like for the next NASSP release and I'll invest some time in getting the manual updated.

 

[riclourenco]

Ok Thanks, I will try that. That manual would be great .

 

[riclourenco]

I tried to do the maneuver on the SIVB. I was able to send commands from "Timebase 8 Enable", but when I tried the "Evasive Maneuver Enable" uplink failed.

https://puu.sh/EDmS3/893b127779.png

https://puu.sh/EDmSB/c75bced21f.png

However, SIVB initiated an ullage.

https://puu.sh/EDmSQ/63bad9f6d2.png

Is this it, or the SIVB engine also ignites? The SIVB does not change the attitude.

In addition, after GET 4h09mim, there is a SPS burn on checklist, although the only evasive maneuver mentioned in the flight plan is with the SIVB .

https://puu.sh/EDmUw/03646358c2.png

I think I'll try to make an SPS ignition pointing toward Earth with a little dv. Then the route can be corrected later with an MCC.

 

[indy91]

I tried to do the maneuver on the SIVB. I was able to send commands from "Timebase 8 Enable", but when I tried the "Evasive Maneuver Enable" uplink failed.

https://puu.sh/EDmS3/893b127779.png

https://puu.sh/EDmSB/c75bced21f.png

However, SIVB initiated an ullage.

https://puu.sh/EDmSQ/63bad9f6d2.png

Is this it, or the SIVB engine also ignites? The SIVB does not change the attitude.

Ah, I got the order of those commands wrong. There is a great timeline for the S-IVB in this document: https://history.nasa.gov/afj/ap12fj/pdf/a12_sa507-flightmanual.pdf

on PDF page 225. You have to send the "evasive maneuver enable" command first, that is usually done just after LM ejection and will make the S-IVB yaw from -40° to +40°. And then when the flight plan calls for it (4:25h GET for Apollo 12) you send the Timebase 8 enable signal, which should immediately start firing the S-IVB ullage thrusters. And if you follow the S-IVB timeline, a bit later it will then do a LOX dump and another ullage thruster burn. That is done automatically though, you only need to send those two commands.

In addition, after GET 4h09mim, there is a SPS burn on checklist, although the only evasive maneuver mentioned in the flight plan is with the SIVB .

https://puu.sh/EDmUw/03646358c2.png

I think I'll try to make an SPS ignition pointing toward Earth with a little dv. Then the route can be corrected later with an MCC.

Ah, just like there is no MCC support for Apollo 12+ there also isn't really any Checklist MFD yet for Apollo 12+. Those missions use our default CSM checklist, which is mostly based on Apollo 8 or 11, I think, and won't cover anything beyond the initial few hours of the mission. I suggest you instead use the flight plan and other checklist from here: https://history.nasa.gov/afj/ap12fj/a12-documents.html

 

[riclourenco]

Ok, thanks Indy91!