NASSP Apollo 8 MCC and Time Accel questions

Wedge313

Well-known member
Joined
Apr 18, 2020
Messages
488
Reaction score
118
Points
58
Location
Boston
Hello (again)....Starting from the Project Apollo-NASSP-Apollo 8 MCC Launch scenario, I've got myself into a parking orbit (well, ok, the LVDC did the work, but I flipped some switches). I have a few questions: First, time acceleration: I'm unable to use anything higher than 6x without the computer locking up (my guess is it's because I'm running Orbiter on a bottom-feeder laptop, but if there's some fix I can try I'd appreciate it). Second, I didn't notice until I was in orbit, but I'm not getting any uplinks from MCC. Both Mission and Ground Tracking are enabled. Now if instead I use the Apollo-mission scenarios-Apollo 8 scenarios, all the uplinks from MCC show up. So I'm not sure what I need to do to get MCC working starting from the MCC Launch scenario. Thanks.
 

Thespacer

Active member
Joined
Oct 26, 2019
Messages
109
Reaction score
44
Points
43
Hi - from what you’ve described - namely you’ve launched a scenario that specifically has MCC enabled - the MCC uplinks should work. What exactly is the issue: do you get the messages saying ”ready for uplink, but the uplink does not proceed to work? Or do you not receive the messages at all?

If the former, then that may be related to a known bug - if you close an orbiter session, but do not close the main client, but then re-load a session, uplinks might not work.
 

indy91

Addon Developer
Addon Developer
Joined
Oct 26, 2011
Messages
1,224
Reaction score
582
Points
128
NASSP is very CPU heavy unfortunately. The main cause is actually outdated code for displaying the panels in the cockpit rather than running multiple emulators and a detailed simulation of everything, although that doesn't help. So best do time acceleration not while you are looking at e.g. the CSM main panel, but some panel with little going on or the outside view. The panel with the mission timer in the lower equipment bay works well for this, also because you have a time reference there when you want to stop time acceleration. But something like the forward hatch would also work. If that doesn't really help you then it's not just the CPU load that is the issue for you and you probably won't be able to use high time acceleration anywhere.

The first MCC update on Apollo 8 doesn't happen until about 1h35min into the mission. Are you at that point yet?
 

Wedge313

Well-known member
Joined
Apr 18, 2020
Messages
488
Reaction score
118
Points
58
Location
Boston
OK, that was a mess.....First, thank you indy91, as you suspected I was ahead of myself, the MCC update worked fine after a short wait. But some other issues came up, and any guidance would be appreciated.

1. Not enough fuel in the S-IV B to accomplish the TLI burn. Before ignition the Oxid quantity was 21 and fuel 23 (no idea what it's measuring, psi?) As a comparison, the canned mission scenario at this same point showed 35 and 35. My burn terminated about one minute early. (I'll get close enough to take a few pictures, but it's going to be a shorter mission than planned.) What have I goofed up to get to this point?

2. Launch question: out of curiosity I looked at the Align Plane MFD and Map MFD before launch, and I'm nowhere near the moon's plane (Rinc around 57). Is this normal? Or should I somehow change to a later launch time to get a better Rinc? (When I'm in the XR-2, Rinc is around 5.6-ish before takeoff). Seems like a lot of plane change, and I'm wondering if that's why I burned so much S-IV B fuel getting into orbit?

3. Once I get the TLI PAD, what do I do with it? It seems to me the S-IV B computer is handling this burn, I don't see anything I'm doing switch-wise or with the AGC to affect the burn, other than entering the dV into the EMS. following along with IMFD, the TLI burn started about two minutes earlier than the solution I had on IMFD, but seemed close enough to get me there- until the early flameout.

4. Auto checklist: when running the checklist in auto, I struggled to get a good P52. PGNS light, PROG light, OPR ERR flashing etc. When I did it manually P52 seemed to go OK, with the exception of seeing F 01 71 when the checklist said F 01 70 after the first mark, and then F 01 70 instead of F 01 71 after the second. But it seemed to work otherwise, the error was within limits. This might be associated with the time accel issue I mentioned?

So I'll save this, and then go back and start from scratch, hoping for a better result? How hard can this be: it's not like it's rocket science. I hope I'm not being too much of a pain, but I need and appreciate the help. Thanks.
 

indy91

Addon Developer
Addon Developer
Joined
Oct 26, 2011
Messages
1,224
Reaction score
582
Points
128
OK, that was a mess.....First, thank you indy91, as you suspected I was ahead of myself, the MCC update worked fine after a short wait. But some other issues came up, and any guidance would be appreciated.

1. Not enough fuel in the S-IV B to accomplish the TLI burn. Before ignition the Oxid quantity was 21 and fuel 23 (no idea what it's measuring, psi?) As a comparison, the canned mission scenario at this same point showed 35 and 35. My burn terminated about one minute early. (I'll get close enough to take a few pictures, but it's going to be a shorter mission than planned.) What have I goofed up to get to this point?

Yeah that's not enough propellant to go through the whole TLI burn. Weird issue, don't think I have ever seen this. You didn't happen to use the S-II/S-IVB LV Stage switch? That causes early staging from the S-II to the S-IVB during launch and then you of course would have less propellant. But I guess that is not what you did...

Did you start with the T-4h scenario or the T-60 seconds one? Notice anything unusual during launch?

2. Launch question: out of curiosity I looked at the Align Plane MFD and Map MFD before launch, and I'm nowhere near the moon's plane (Rinc around 57). Is this normal? Or should I somehow change to a later launch time to get a better Rinc? (When I'm in the XR-2, Rinc is around 5.6-ish before takeoff). Seems like a lot of plane change, and I'm wondering if that's why I burned so much S-IV B fuel getting into orbit?

Could be related to the issue, maybe it somehow used the wrong insertion orbit during launch. But again, that is not something I have ever seen before.
3. Once I get the TLI PAD, what do I do with it? It seems to me the S-IV B computer is handling this burn, I don't see anything I'm doing switch-wise or with the AGC to affect the burn, other than entering the dV into the EMS. following along with IMFD, the TLI burn started about two minutes earlier than the solution I had on IMFD, but seemed close enough to get me there- until the early flameout.

Yeah, you don't have much influence on the burn other than monitoring it. You can inhibit TLI with a switch and take control of the burn (although not during Apollo 8 yet). I wouldn't be worried too much about what IMFD says, as long as there is no other issue (like maybe the one that causes your low propellant level...) then targeting and guidance wise it will do the right things.
4. Auto checklist: when running the checklist in auto, I struggled to get a good P52. PGNS light, PROG light, OPR ERR flashing etc. When I did it manually P52 seemed to go OK, with the exception of seeing F 01 71 when the checklist said F 01 70 after the first mark, and then F 01 70 instead of F 01 71 after the second. But it seemed to work otherwise, the error was within limits. This might be associated with the time accel issue I mentioned?

Hmm, not sure, I doubt it has to do with time acceleration. Maybe have a look at the P52 procedure (like in this actual Apollo 8 checklist, PDF page 38) and study all the steps a bit. When you know all the steps then you can maybe detect where the auto checklist does something that isn't correct. Of course even with the auto checklist you will still have to do at least the marks manually.
 

Wedge313

Well-known member
Joined
Apr 18, 2020
Messages
488
Reaction score
118
Points
58
Location
Boston
So, hypothetically.....if someone were to forget to disable their joystick before running NASSP, and then later during an Apollo 8 launch inadvertently move or bump the joystick, could that cause the S-II to shutdown/stage early? (Asking for a friend)
 

indy91

Addon Developer
Addon Developer
Joined
Oct 26, 2011
Messages
1,224
Reaction score
582
Points
128
Ah yes, that does still work. You can change the thrust of the S-II like you would for any other vehicles in Orbiter and you can completely shut down the engines the same way as well. That shouldn't work, but it still does. So it's definitely not safe to e.g. move the throttle lever of a joystick during the launch.

The S-II engines are defined as "main engines" for Orbiter, which means the user has access to the engines with + and - keys on the Numpad etc. We can define them as "custom engines" instead, then you wouldn't have any control with the joystick or Numpad of it. Only issue is that Orbiter Sound then doesn't play engine fire audio for it. So we need to implement a bunch of sound code for the main engines then, which is something we have already done for the CSM RCS and LM RCS. So sadly you ran into an issue that still exists out of developers laziness. But not bumping your joystick would have helped. :D

But yeah, that probably explains your low propellant level. I guess you just have to try again from launch.
 

Wedge313

Well-known member
Joined
Apr 18, 2020
Messages
488
Reaction score
118
Points
58
Location
Boston
Your comment about early staging was my clue. My joystick has a point-of-view button, and just before (scheduled) staging I had switched to external view. At the time I thought it only coincidental that staging occurred at the same time I tried to adjust the POV ("It was a glitch! A technical malfunction!) I re-ran the launch, with joystick disabled, and achieved orbit with much more fuel. I will proceed with TLI and see how that goes.
 
Top