Question Apollo 2: AS-208 Launch Questions

[Wedge313]

Hello,

Working through the Apollo 2 scenario. I'm 5+46 into the flight, after SPS-1. I was looking ahead on the MFD Checklist to find where I'm supposed to launch Spider, and I see that the checklist expects me to be conducting the rendezvous at 22:25. But looking at the RTCC Inputs guidance sheet it doesn't look like I'm supposed to launch Spider until around 38:30.

I've missed something somewhere, or I'm not following the sequence of events correctly. Can you get me back on track?

Thanks

 

[Max-Q]

That 38 hours is referenced off of midnight on AS-205's launch day.
That's the timekeeping system that RTCC uses, don't worry you will launch at around 23 hours GET.

 

[Wedge313]

Question re: changing the AS-208 launch time. In the RTCC I only had to fudge the TLO by 1.8 seconds (38:30:13.8) to get the INS PHASE to -1.001. Does that sound right?

And in the .scn, the AS-208-S4BSTG MISSNTIME and LC37 LAUNCHMJD are both in MJD format. Do I just convert the launch time in hours (July 29, 1968 at 14:30:13.8) to MJD (I get 40066.522138?) and use that time to edit the MISSNTIME and LAUNCHMJD values?

Thanks.

 

[Max-Q]

Question re: changing the AS-208 launch time. In the RTCC I only had to fudge the TLO by 1.8 seconds (38:30:13.8) to get the INS PHASE to -1.001. Does that sound right?

I'd go 2 seconds even and call it good.
The phase isn't super important, just as long as it's close to -1.

And in the .scn, the AS-208-S4BSTG MISSNTIME and LC37 LAUNCHMJD are both in MJD format. Do I just convert the launch time in hours (July 29, 1968 at 14:30:13.8) to MJD (I get 40066.522138?) and use that time to edit the MISSNTIME and LAUNCHMJD values?

AS-208-S4BSTG MISSNTIME is in seconds until launch. So, just add/subtract (Add 2 seconds in you case) directly to it.
LC37 LAUNCHMJD is a little harder. The way I would do this is copy the current LAUNCHMJD into the Date.exe utility that comes with orbiter, add the two seconds, and copy the resulting MJD back into the scenario.

 

[Wedge313]

I'm missing something. I've gone through this a few times but I haven't been able to get AS-208 to launch.

I'm attaching a saved scenario from about 3 minutes before launch (7/29/68 14:27:28), could you look at my edits to the MISSNTIME and LAUNCHMJD and let me know where I'm going wrong?

Here's what I'm trying for: launch July 29, 1968 at 14:30:14. I worked that out to be a MJD of 40066.604329, which I input as LC37 LAUNCHMJD. The AS-208-S4BSTG MISSNTIME (which I now understand is counting down to launch) has counted down as of this save to -163.543268, which when added to the time of this save gives me a launch at 14:30:14.

I followed the RTCC steps to uplink the info to the AS-208 IU, and got the "Uplink Accepted!" message.

But at 14:30:14 nothing happens.

I know I'm messing up somewhere, but I'm stumped.

Thanks

EDIT: Removed attached flawed scenario to avoid embarrassment.

 

[Wedge313]

UPDATE: After digging around I think I got it straightened out. Not sure what happened, but it was probably just some sloppy copy/paste on my part.

So, AS-208 is in orbit. Right now it looks like Gumdrop's orbit is behind AS-208. Was that the desired orientation?

 

[Max-Q]

UPDATE: After digging around I think I got it straightened out. Not sure what happened, but it was probably just some sloppy copy/paste on my part.

What ended up being the matter? I couldn't get it to launch either.

So, AS-208 is in orbit. Right now it looks like Gumdrop's orbit is behind AS-208. Was that the desired orientation?

You want AS-208 to ahead of Gumdrop by about 60 miles at insertion.
Gumdrop is in a lower orbit, thus flying faster, and will catch up over the course of the rendezvous.

 

[Wedge313]

What ended up being the matter? I couldn't get it to launch either.

It looks like on my first edit attempt I somehow deleted two lines in the LC37 section, the "S1BNAME" and "SIVBNAME" lines. And for some reason I labeled this as my baseline "before editing" scenario (?), so all my attempts to correct the problem had this error included.

I finally went back to my original un-edited save just before the edit, and comparing the two picked up the error.

As seems to always be the case with NASSP, most of my problems are self-induced.

Thanks.

 

[Max-Q]

As seems to always be the case with NASSP, most of my problems are self-induced.

I wouldn't say that, NASSP is hard and we all have to learn somewhere.
Anyone who can even attempt Apollo 2 is pretty good at NASSP.

 

[rcflyinghokie]

It looks like on my first edit attempt I somehow deleted two lines in the LC37 section, the "S1BNAME" and "SIVBNAME" lines. And for some reason I labeled this as my baseline "before editing" scenario (?), so all my attempts to correct the problem had this error included.

I finally went back to my original un-edited save just before the edit, and comparing the two picked up the error.

As seems to always be the case with NASSP, most of my problems are self-induced.

Thanks.

I will also go on record as saying you are one of the few to fly the 13 failure mission, and also find bugs/inaccuracies! So don't sell yourself short!

 

[Wedge313]

It was fun doing the Apollo 13 flight! It's in my top two favorites (so far), along with Apollo 15. And I'm enjoying Apollo 2, I'm working through the rendezvous now and I'm sure I'll have a lot of questions coming up.

And let me go on record saying that I appreciate all the help all of you have given me! I couldn't get through any of these missions without the guidance you've provided. I continue to be blown away by NASSP; the work you've all put into it is greatly appreciated.

 

[Max-Q]

I'm working through the rendezvous now and I'm sure I'll have a lot of questions coming up.

All I can say is, Save fuel! Seriously, Apollo 2 will push the SMRCS fuel to the absolute limit.

 

[Wedge313]

Hey! Look what happened!

All I can say is, Save fuel!

Well, I flunked that part. I developed a large closing rate and used a ton of RCS to finally get the two ships into some semblance of formation.

I'll call this attempt a "proof of concept" and go back and try to get it done a bit more efficiently.

 

[Max-Q]

Well, I flunked that part. I developed a large closing rate and used a ton of RCS to finally get the two ships into some semblance of formation.

How much you got left?
If you're over 50% left at docking in all four quads, you will have enough to complete the full mission, assuming you are very careful with usage.

 

[Wedge313]

How much you got left?

After my first attempt I had about 65% in quads A&C and 58% in quads B&D.

On my fourth try I ended up with about 76% in quads A&C and 70% in quads B&D.

My first stupid question is: Am I reading the RCS propellent quantity correctly? The gauge is labeled "psia", and I'm ball-parking a percentage based on the indicator position.

Second Question: I ran through the sequence after the TPI burn four times. I've tried to follow the procedure on the checklist MFD, but I get a little confused at the point before the first mid-course correction. I've finished my fifth mark, and after getting the F 06 49 I hit PRO. The checklist says "Last Mark being processed" Do I wait for anything at this point? Or just hit PRO again to get to the "Accept Marking Sequence" and "Marking Sequence being processed" step? After the second PRO the checklist has me looking for a F 06 89, which I'm not getting. I just get a F 06 49 at this point. Another PRO gives me the F 16 45.

Thanks

 

[Max-Q]

After my first attempt I had about 65% in quads A&C and 58% in quads B&D.

On my fourth try I ended up with about 76% in quads A&C and 70% in quads B&D.

You have plenty. My rule is if you are above 60% there is enough, as long as you are careful.

My first stupid question is: Am I reading the RCS propellent quantity correctly? The gauge is labeled "psia", and I'm ball-parking a percentage based on the indicator position.

Yes, you are.

Second Question: I ran through the sequence after the TPI burn four times. I've tried to follow the procedure on the checklist MFD, but I get a little confused at the point before the first mid-course correction. I've finished my fifth mark, and after getting the F 06 49 I hit PRO. The checklist says "Last Mark being processed" Do I wait for anything at this point? Or just hit PRO again to get to the "Accept Marking Sequence" and "Marking Sequence being processed" step? After the second PRO the checklist has me looking for a F 06 89, which I'm not getting. I just get a F 06 49 at this point. Another PRO gives me the F 16 45.

This part is copied directly from the Apollo 7 checklist, I think there may be some typos in there.
Honestly, it's a bit confusing for me as well...

 

[Wedge313]

I may have inadvertently stuck an extra PRO in there at some point or another, but the AGC got us to the SIVB in spite of my efforts.

I think I'll call the rendezvous complete and press on. Thanks!

 

[Wedge313]

Coming out of the first rest period we have to calculate a Docked DPS REFSMMAT. The RTCC Inputs guide walks you through this process pretty well, but I want to check if I did the "Verify REFSMMAT Identical" step correctly.

After switching the focus vessel to the CSM, I navigated the RTCC to the P30 REFSMMAT page. I couldn't figure out how to get the info to match the REFSMMAT we calculated in the LM. I ended up repeating the "G00,LEM,CUR,CSM,CUR;" step, and that populated the page with the identical info as in the LM REFSMMAT, except there was no Time or DV info displayed. I uplinked that REFSMMAT to the CSM computer.

Am I on the right track?

 

[Max-Q]

Yeah, sounds right.
The dVs and TIG won't carry over, but the nine REFSMMAT values should be the same.

 

[Wedge313]

During the LM cold fire check, everything looks good except translation up/down, checklist says R1 00252/00125, I get 00210/00021. Is this an issue?