Apollo 15 Post Orbital Insertion Procedures Question

[Wedge313]

Did you do a AOT star check with P52

Yes, and that wasn't centered. It was right on the Y axis but a bit above the X axis, not too far off but not centered.

 

[Wedge313]

I did another P52 and took two pictures of the check results so you get an idea of what I'm looking at, and maybe you can tell if I'm in the "close enough for government work" range. Or not.

On this try I ended up with a star angle difference of +00001, and my gyro angles were +00131, -00084, and +00106.

And while doing this procedure I realized I don't fully understand the functions of the Attitude Control and Mode Control switches, the 4 JET/2 JET switch, and how they interact. I thought I had a grip until I turned off the ACA/4 Jet hard over switch, and then realized I'm sort of clueless ( Where can I get an explanation of the function of these switches? I couldn't find anything.)

Thanks

 

[indy91]

The star angle difference and gyro torquing angles look good. For the star check, the LM is in an attitude hold which has a deadband, probably 1°, so it won't point exactly at the star. Not like the sextant in the CSM which will point exactly where the CMC commands it to. Maybe just wait for a moment and look if the LM points correctly on average.

For the switches involved in attitude control, the AOH has a list of all switches and what they do. A bunch of them only have a function when the AGS is in control.
https://www.hq.nasa.gov/alsj/LM10HandbookVol1.pdf start reading on PDF page 659.

 

[Wedge313]

Thanks, that's exactly what I was looking for.

Question: my landing radar check is off, my tape meter reads 8290 and rate -494, both out of tolerance (8000 +/- 100, -480 +/- 2). But the N65 values were all good. Anything I can do here?

I don't even understand enough about the AGS yet to ask questions. I'm just following the timeline, reading the AOH and hoping for the best. I'm sure nothing good will come from that.

 

[rcflyinghokie]

Question: my landing radar check is off, my tape meter reads 8290 and rate -494, both out of tolerance (8000 +/- 100, -480 +/- 2). But the N65 values were all good. Anything I can do here?

You mean when doing the LR test? If so I think our test signals are hardcoded, I don't know if the ones for the J missions are implemented they might be driving to a signal expected from an earlier mission.

 

[Wedge313]

OK, can't avoid it any longer, time to get into the AGS. In the LM Timeline Checklist at T 104:06ish it's asking to "COPY AGS RLS (231)", where do I get that? And in the RTCC there's an AGS SV PAD (no 231 entry), what do I do with that?

EDIT: found the 231 entry, it was on the PDI PAD.

EDIT: Ehhh, who needs the AGS, I never intended to abort anyway.

Despite everything I got on the ground at Hadley! Not pretty but any landing you can walk away from is a good one, and if the the ship will still fly it's a great one.

But I would like to go back and get the AGS squared away.

 

[indy91]

Address 231 has the radius of the landing site. Unless you are changing the landing site based on some P22 tracking the pre-mission value loaded in the AGS should be fine. Once you are landed the Ascent PAD provides an updated value with your actual landing site (after you have updated the landing site in the RTCC on the Landing Site Update page). There is probably not really a good way to generate that number in the RTCC MFD for the AGS other than the Ascent PAD. You could manually convert the number the e.g. Landing Site Update page shows from nautical miles to 100s of feet. NM is the unit the RTCC shows, the unit in the AGS is 100 feet.

 

[rcflyinghokie]

Address 231 has the radius of the landing site. Unless you are changing the landing site based on some P22 tracking the pre-mission value loaded in the AGS should be fine. Once you are landed the Ascent PAD provides an updated value with your actual landing site (after you have updated the landing site in the RTCC on the Landing Site Update page). There is probably not really a good way to generate that number in the RTCC MFD for the AGS other than the Ascent PAD. You could manually convert the number the e.g. Landing Site Update page shows from nautical miles to 100s of feet. NM is the unit the RTCC shows, the unit in the AGS is 100 feet.

Looks like you beat me again! The PDI PAD page of RTCC also shows DEDA 231 as well.

 

[Wedge313]

Oops, missed your responses. Yeah, the LGC got me down fine. But I want to go back and get comfortable with the AGS, I'm just punching in numbers, don't really understand what I'm doing.

Thanks.

 

[rcflyinghokie]

Oops, missed your responses. Yeah, the LGC got me down fine. But I want to go back and get comfortable with the AGS, I'm just punching in numbers, don't really understand what I'm doing.

Thanks.

The AGS procedures in the G&N dictionary and the AGS operating manual (FP8 for 15) will probably help quite a bit.

And of course if you have specific questions feel free to ask!

 

[rcflyinghokie]

OK, can't avoid it any longer, time to get into the AGS. In the LM Timeline Checklist at T 104:06ish it's asking to "COPY AGS RLS (231)", where do I get that? And in the RTCC there's an AGS SV PAD (no 231 entry), what do I do with that?

EDIT: found the 231 entry, it was on the PDI PAD.

EDIT: Ehhh, who needs the AGS, I never intended to abort anyway.

Despite everything I got on the ground at Hadley! Not pretty but any landing you can walk away from is a good one, and if the the ship will still fly it's a great one.

But I would like to go back and get the AGS squared away.

Just curious, where did you actually end up landing? Mind posting the new landing site coordinates?

I ask because I had to do a few updates to the landing site to avoid the rille.

 

[thermocalc]

ahahahaha---you made it Wedge313......GREAT JOB.
I am studying the AGS for A11 in these days (FP6), the AGS manual helps really a lot to get the hands on it, for you FP8, but the AGS manual is quite "readable" and quite "clear" ... compared all others AOHs
keep going....

 

[Wedge313]

Just curious, where did you actually end up landing? Mind posting the new landing site coordinates?

Well, uhh....not sure where it wanted to land, but I ended up at 26.07N 003.7E.

I say that because I was fixating on the DSKY, watching P64 switch to P66, my scan was non-existent and I picked up an aft drift that had the cross-pointer smashed up hard against the bottom of the instrument. So I ended up a bit uprange of where it would have wanted to touch down, but maybe 100-200 yds?

 

[rcflyinghokie]

Well, uhh....not sure where it wanted to land, but I ended up at 26.07N 003.7E.

I say that because I was fixating on the DSKY, watching P64 switch to P66, my scan was non-existent and I picked up an aft drift that had the cross-pointer smashed up hard against the bottom of the instrument. So I ended up a bit uprange of where it would have wanted to touch down, but maybe 100-200 yds?

Not too bad, I am just making sure it didn't fly you past the rille

 

[Wedge313]

Well whatever you guys have been doing with NASSP it all worked great, in spite of my efforts to gum it up.

I'm curious if I'll be able to spot the LM from the CSM? If I have the ship markers on?

EDIT: I just saw the pin you placed at my landing spot. I'm surprised I'm that far away from the rille. When I pitched over I thought I was going to land in it! I was trying to figure out what was going on with the LPD, looking at the G&N P63 procedure, attempting to arrest my forward velocity and I developed a huge aft velocity, maybe if I had just left it alone it would have been better. I'll run it a few times now that I have a feel for what to expect and see how it works out

 

[rcflyinghokie]

Well whatever you guys have been doing with NASSP it all worked great, in spite of my efforts to gum it up.

I'm curious if I'll be able to spot the LM from the CSM? If I have the ship markers on?

I was able to spot from orbit last time I tried Hadley is one of the easier ones I have found to spot the LM

 

[Wedge313]

So I ended up about 1.5 miles away from Falcon? Well, that's ok, I like my privacy and I'm good at social distancing. But still close enough if I need to borrow a PLSS or something.

 

[Wedge313]

This morning I re-did the P63 procedure twice from just before ignition, this time I let the LM do what it wanted and didn't re-designate the landing spot. Both times after landing when I ran V37 N68 I ended up with LAT 026.07 and LON 003.65, which on a lunar map seems to put me just north of Earthlight Crater. But on my visual I am in Hadley Rille (?). Not sure what is up with that.

 

[rcflyinghokie]

This morning I re-did the P63 procedure twice from just before ignition, this time I let the LM do what it wanted and didn't re-designate the landing spot. Both times after landing when I ran V37 N68 I ended up with LAT 026.07 and LON 0036.5, which on a lunar map seems to put me just north of Earthlight Crater. But on my visual I am in Hadley Rille (?). Not sure what is up with that.

Are you using the add on textures for Hadley? http://absimp.org/orbitersim/apollolandingsites.html

Also you need to run P68, V37 N68 wont call the program.

 

[Wedge313]

Are you using the add on textures for Hadley?

No! I didn't know those existed. I'll get that done.

Also you need to run P68, V37 N68 wont call the program.

I misspoke, I did run P68 (V37E N68E), and that's the LAT/LON I get.