Meadville Space Center

Project Apollo - NASSP => Project Apollo - NASSP Development => Topic started by: Puma on January 03, 2017, 12:02:50 PM



Title: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 03, 2017, 12:02:50 PM
I am doing the Apollo 7 Mission in Orbiter 2010, NASSP Version: NASSP-V7.0-RC-master-313 built. When performing P52 IMU Realign I get this error in the Apollo DSKY : OPP ERR, I uploaded the Following video, so you may understand what is going on:

https://www.youtube.com/watch?v=xzJdZfLEQBc&feature=youtu.be

I also uploaded the Scenario as you can see. I hope you could help me solving this problem, since I really love this addon and I want to finish that mission. Thanks.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 03, 2017, 12:55:00 PM
Well, you are also getting a bunch of program alarms. When did these start happening? Must have been a previous P52 attempt?! If you look at the alarm codes (Verb 5 Noun 9), then you see:

112: Mark rejected
1520: V37 not permitted at this time
122: Marking not callled for

From the video I know you have the Checklist MFD running, although you don't have the MFD itself up. You don't have the automatic checklist execution on, right? You would have enabled this in the Orbiter launchpad and it would do all the switch settings for you. If that were the case, then the Checklist MFD could have automatically done something bad.

When I then start P52 I get another program alarm:

220: IMU orientation unknown

So somewhere the alignment went bad. Did you maybe not properly end a previous P52 maybe? In any case you could probably recover by doing a P51 and then a P52, then you will have a IMU orientation again. But let's find out first why you lost the alignment in the first place...


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 03, 2017, 02:26:19 PM
I followed every step of the checklist, it is not automatic. I done it by my self by following the Apollo checklist mfd, but since I recorded the video by using Fraps, it does not show up in the video, I know is weird, maybe because I use the external mfd? could you write down the exact procedure to correct these, I do not want to start it over, the Apollo checklist mfd does not show you any message if you do something wrong, I swear I followed everything what the  the Apollo checklist mfd, why I can not see those alarms you mention, does it are not suppose to sound?


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 03, 2017, 02:38:44 PM
The program alarm is just in the AGC and it doesn't cause a master alarm with sound. You can see it because the PROG light on the DSKY is on. When did the PROG light go on? Before or during the P52? If it was before that, then the problem might not have started from a P52.

External MFD shouldn't cause any problems. I believe that you followed every step, so potentially (although unlikely) there is a problem with the checklist. That is one of the last things we have to get right before the 7.0 release.

Do you not have a scenario close to the one you attached above? I would try it with a previous scenario, but if you haven't saved in a while then you should first press RSET (to make the program alarms go away) and then give the IMU a new alignment. You do that by first going through P51 and then P52. The checklist for P51 can be found under "\Doc\Project Apollo - NASSP\Word Checklists\G&C Checklist.doc". For the P52 you should probably use option 2 with a GET Align (Noun 34) of maybe 13 hours GET.

But I still would like to find out what went wrong, or the problem might repeat itself for the next P52.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 03, 2017, 03:11:53 PM
Could you fix the scenario? I'll really appreciate it


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 03, 2017, 03:33:58 PM
Ok, I think I just found out what happened. It actually was a Checklist MFD problem! Kind of.

You are using the scenario with the MCC mission tracking. Occasionally the MCC will calculate some stuff and display e.g. a Maneuver PAD, which you have probably noticed. What the MCC is also doing is providing automatic uplinks, so that you don't have to go through a MFD for that. However, you still have to allow the uplink by setting the UPTLM CM switch to Accept and in the MCC/CAPCOM menu you have to basically tell Houston "you can uplink now." This can be done by opening the menu (TAB) and then press "2". The Checklist MFD didn't tell you that, because when I created the file I was too lazy to write a checklist for the automatic uplinks. It's really only a few steps and I wasn't sure yet if the checklist should be for the MCC or non-MCC scenario. The Apollo 8 Checklist MFD file already has the uplink checklist and the plan was then to use the same thing for Apollo 7. I don't remember, either @jalexb88 or @rcflyinghokie wanted to change this in the Apollo 7 checklist, but they haven't gotten around to it yet.

How did this missed uplink cause the problem? Well, one of the uplinked data was a "Desired REFSMMAT". This is essentially the new alignment that you aligned the IMU to with a P52 Option 1 (Preferred Alignment) at about 5:10h GET. The uplink didn't happen so the IMU was aligned to garbage data in the AGC memory. That's causing all the problems with program alarms and preventing you from doing a P52.

I will fix the scenario for you and we really should put the short uplink checklist in the Apollo 7 Checklist MFD file very soon. Just remember that whenever the MCC displays the message "Ready for Uplink?" to do the two steps I explained above, UPTLM CM to Accept and then in the CAPCOM Menu start the uplink. The Checklist MFD will often just display a yellow "Copy Maneuver PAD" text for this. So that is your cue to check if MCC wants to do an uplink.

EDIT: Here the fixed scenario. The Checklist MFD should still be at the right place. I have just started the P52 (option 3 as you tried before) and it should all work this time.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 03, 2017, 04:00:04 PM
Huge Thanks!

Excellent! I will wait for that Scenario fix so I can continue this wonderful mission, you may post the scenario also here so if the same thing had happened to other they may continue also. I thought that everything that should be done within an specific mission from launch until landing were already included in Apollo Checklist mfd, I think the mfd is a great idea for people who wants to do those missions as the real astronaut did them, there are a lot of great ideas than can be included inside the Apollo checklist mfd, does orbiter recognize user inputs, I mean if something is done wrong, can the checklist tell that to the user? I notice that the yellow letters are direct input for the users, is any chance maybe in the future, I don't now that the checklist tells you everything you need to do, reading stuffs outside of the simulation make it loss the realistic momentum, once you are immerse within a mission is kind of annoying reading documentation from out side, it losses the realism, do you think is possible that in some near future that can be done? in other hand here I upload all the steps I have been through now in this mission, I hope it could help you to find those little bugs and for making this addon the best! Thanks.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 03, 2017, 04:12:36 PM
Scenario is already attached above.  :D

Quote
I thought that everything that should be done within an specific mission from launch until landing were already included in Apollo Checklist mfd, I think the mfd is a great idea for people who wants to do those missions as the real astronaut did them,

I think I recently mentioned it another thread, creating checklists that are 100% correct for a 260 hour mission is kind of difficult. We try our best, but there will always be smaller issues.

Quote
there are a lot of great ideas than can be included inside the Apollo checklist mfd, does orbiter recognize user inputs, I mean if something is done wrong, can the checklist tell that to the user?

The Checklist MFD can only really recognize switches being set and that kind of stuff. It doesn't do a more complicated evaluation of the state of the spacecraft. But it does read the state of e.g. the EMS DV Counter. So it does recognize if the number in there is correctly set.

Quote
I notice that the yellow letters are direct input for the users, is any chance maybe in the future,

The yellow text is checklist items that can't be automated or don't have an associated switch setting. Writing down a Maneuver PAD, moving the sextant exactly above a star, all this can't really be recognized by the Checklist MFD as correct.

Quote
I don't now that the checklist tells you everything you need to do, reading stuffs outside of the simulation make it loss the realistic momentum, once you are immerse within a mission is kind of annoying reading documentation from out side, it losses the realism, do you think is possible that in some near future that can be done?

We try to make the Checklist MFD a complete "mission walkthrough" as much as possible. But I personally also like having the checklists printed out. After all the astronauts did have all the checklists with them, so it is certainly more realistic than using the Checklist MFD.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 03, 2017, 10:13:20 PM
Where do I can find A GOOD Apollo 7 step by step tutorial for NASSP, I get stuck must of the time, there is not so much explanation in the checklist. do any one have completed this mission ever? why I ca not see any video tutorial on YouTube?


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 04, 2017, 02:28:18 PM
Where do I can find A GOOD Apollo 7 step by step tutorial for NASSP

I'm not sure there are many. There is an extensive French tutorial by nulentout, although it is probably fairly outdated by now. That's the thing, up until a few months ago there were some big changes and longer tutorials could be obsolete quickly. Maybe some more will be created now that we are close to release NASSP 7.0.

Quote
I get stuck must of the time, there is not so much explanation in the checklist

The checklist is not a tutorial. It let's you do most things step by step, but they aren't really great for actually learning about the systems, the AGC etc. There is a bunch of reading you can do in our wiki: http://nassp.sourceforge.net/

Quote
. do any one have completed this mission ever?

Oh, yes. Apollo 7 twice and Apollo 8 once. So, it can certainly be done.  :ThumbsUp432:

Quote
why I ca not see any video tutorial on YouTube?

I only know about a P51 tutorial by macieksoft (https://www.youtube.com/watch?v=Kgsw3_d8fkc) and a few video by Bunyap (https://www.youtube.com/playlist?list=PLoiMNu5jyFzTYZTyuz0PNuDWNqEgPgZyJ and https://www.youtube.com/playlist?list=PLoiMNu5jyFzScawrDjlRIpfnsZ5qPlCAM). Some older videos, partially by Bunyap, can also be found here: https://sourceforge.net/projects/nassp/files/Videos%20and%20Multimedia/Project%20Apollo%20-%20NASSP%207/


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: meik84 on January 04, 2017, 04:18:54 PM
Quote
do any one have completed this mission ever?
Sure. Apollo 8 at least 3 times, Apollo 7 one or two times. Though I have to confess that I often skipped P23's for 8 and didn't run the extensive system shakedown for 7. I know that I can shot stars fairly well and I'm quite confident that our systems work as programmed. :wink: In this regard I can only praise Indy's new RTCC MFD. Before we had it, maneuver calculations were a pain in the -well! Now it's 3 clicks and you're done. Amazing! :ThumbsUp432:
On the tutorials: I chewed through the AOH vol 1 those days. Not the easiest read, but hey -it's a really complex spacecraft!


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 04, 2017, 07:55:17 PM
I think I just discovered what caused the error, I think.. First question is: are P51 supposed to be first in the checklist than P52 or not? since the Apollo checklist mfd never showed me the process, it jumped directly to the P52 program, if this is the case is logical at all to get that error, I noticed that in the first Alignment I tried to perform was in fact P52 instead of P51, I uploaded the scenario so you may check it by your own and if you note the mission time above MET and also that the SXT and the telescope was still covered, that indicates a (of course in case P51 is first than P52) an Apollo checklist mfd bug. if this is the case is logical 100%, so it is a Apollo checklist mfd problem, I wish that some of the experts in NASSP could help me clarify that doubt. Thanks.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 05, 2017, 03:14:13 AM
In this regard I can only praise Indy's new RTCC MFD. Before we had it, maneuver calculations were a pain in the -well! Now it's 3 clicks and you're done. Amazing! :ThumbsUp432:

And with the MCC functionality it is 0 clicks! Well, one for uplinks I guess.

I think I just discovered what caused the error, I think.. First question is: are P51 supposed to be first in the checklist than P52 or not? since the Apollo checklist mfd never showed me the process, it jumped directly to the P52 program, if this is the case is logical at all to get that error, I noticed that in the first Alignment I tried to perform was in fact P52 instead of P51, I uploaded the scenario so you may check it by your own and if you note the mission time above MET and also that the SXT and the telescope was still covered, that indicates a (of course in case P51 is first than P52) an Apollo checklist mfd bug. if this is the case is logical 100%, so it is a Apollo checklist mfd problem, I wish that some of the experts in NASSP could help me clarify that doubt. Thanks.

Nope, I explained a few posts above what happened. You didn't accept the automatic uplink at 4:45h GET (because the Checklist MFD didn't tell you that; it does now with revision 314). Part of this uplink was the "Desired REFSMMAT", vitally important for a successful P52 option 1 at about 5:10h GET. The uplink didn't happen so that P52 aligned the IMU to garbage data in the memory, which caused the later problem with P52.

You do not usually have to use P51. P51 is only used if you have lost alignment because of a problem or if you have powered down the guidance systems for the night (which was done during Apollo 7) and you need to get a new, initial alignment. During a normal lunar mission P51 wasn't used. Apollo 7, being the first manned Apollo mission, practiced all these procedures, so later in the flight you will do a few P51s.

Also, the jettison of the optics cover is part of the checklist in the Checklist MFD. It's a yellow text saying "OHC - max right" or so. OHC being the Optical Hand Controller, which is what you are using the WASD keys.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Thymo on January 05, 2017, 07:20:00 AM
Part of this uplink was the "Desired REFSMMAT", vitally important for a successful P52 option 1 at about 5:10h GET. The uplink didn't happen so that P52 aligned the IMU to garbage data in the memory, which caused the later problem with P52.

Does the AGC actually simulate garbage data being in memory if that address hasn't been set to anything or is it just zeroed? Would be kinda cool.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 05, 2017, 07:40:35 AM
Does the AGC actually simulate garbage data being in memory if that address hasn't been set to anything or is it just zeroed? Would be kinda cool.

No, it should be zero if the memory address wasn't used before. I wondered about this, too. In the scenario he posted the addresses for the Desired REFSMMAT are all zero. No idea if they were set to zero again at some point or if that was still the case when he tried the P52 option 1. Not sure how the AGC reacts to such a bad Desired REFSMMAT. The actual REFSMMAT in the scenario is not all zeros, so maybe he didn't complete that P52 and the REFSMMAT wasn't overwritten? But there are a bunch of program alarms in the scenario, even preventing a P52, so the alignment is certainly lost.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: dseagrav on January 05, 2017, 07:44:55 AM
It would be zeroed in real life; Cores are magnetic and have negative state (all zeroes, or all ones if the memory signals are active low instead of high) if never set. By the time the AGC is mounted in a spacecraft the memory will have been initialized to zero during or after the acceptance tests.

You may be thinking of bit rot; That's a different phenomenon (and we don't simulate it)


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 05, 2017, 07:51:10 AM
Just tried a P52 option 1 with a Desired REFSMMAT of all zeros. It lets me progress through the new IMU angles all the way until the first star is automatically chosen and then it throws me out of P52 with a 1301 program alarm, which is: "Arcsin or arccos input is greater than one". That alarm makes sense, if the REFSMMAT is so bad then some of the calculations with the REFSMMAT will break down. The actual REFSMMAT is still intact in the scenario, so it certainly looks like that this is what happened to @Puma.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 05, 2017, 09:31:01 AM
Thank you for your quick response, could you explain Desired REFSMMAT and what I should do with it? in other hands can I fix my current mission by doing a P51? Thanks.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: indy91 on January 05, 2017, 09:57:16 AM
Sure. The actual REFSMMAT of course defines an orientation with respect to the stars, so that with a current IMU alignment the AGC is able to find stars and celestial bodies. It is chosen so that e.g. for launch the pitch angle of the IMU is 90.  Throughout a mission this orientation is changed sometimes. It might be chosen so that during a burn the IMU angles are 0, 0, 0. In the process of changing this orientation, changing the REFSMMAT, you don't want to loose your alignment. So the REFSMMAT that you want to use after an alignment, the so called "Desired REFSMMAT", is just the new REFSMMAT stored in a temporary location until the P52 option 1 is done. At that time the Desired REFSMMAT is copied into the memory location of the actual REFSMMAT.

The AGC itself can calculate a Desired REFSMMAT. You would give the AGC the burn parameters in P30, then go into P40 for a short time and then do a P52 option 1. This might sound complicated, but you will do that a few times later in the Apollo 7 mission. The other source of a Desired REFSMMAT is a ground uplink. In this case the ground has done some calculations for the REFSMMAT that the AGC can't do. This uplink is the one you missed at 4:45h GET. And trying a P52 option 1 without a Desired REFSMMAT causes bad things to happen, as you have noticed.

A few posts above I already posted a fixed scenario for you. If you really want to try to fix it yourself, then you just have to do the steps I did. The uplink was still stored in the scenario, so I first accepted the uplink. I described the procedure in the post with the fixed scenario. Then I did a P51 to get an initial alignment and then I did a P52 option 1 to align the IMU to the uplinked REFSMMAT.


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: Puma on January 05, 2017, 10:34:30 AM
all those thing should be included in the checklist? is this really realistic? I mean does the astronauts this all this in that way? for me it looks more as a flying controller simulator than a space flight simulator, maybe I am wrong. Have you ever tried this:

https://www.indiegogo.com/projects/go-for-launch-mercury-vr-educational#/

you may download the free demo here:

https://dl.orangedox.com/r9vGCk0tbGhIEMTSDV

Is there any chance that Orbiter could be something like that?


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: meik84 on January 05, 2017, 01:34:36 PM
Quote
all those thing should be included in the checklist? is this really realistic?
It should be in the word checklist at least, but I don't think we have to include a contingency/recovery procedure (which it is, IMHO) in checklist MFD.
Quote
I mean does the astronauts this all this in that way?
The CMC runs the original software, so yes, they did. And yes, they sometimes messed up with the CMC, too. Jim Lovell caused an average 'Ooops!' on Apollo 8 (which almost got him an unscheduled EVA -Frank Borman intended to throw him out of the window for that) and had to do the whole P51/P52 smash, just like you.
Quote
for me it looks more as a flying controller simulator than a space flight simulator
*shrug* Spaceflight is the culmination of engineering, so don't expect too much action... :wink: Many Apollo astronauts held degrees in mechanical, electrical or aeronautical engineering. Buzz Aldrin held the nickname 'Dr. Rendezvous' because he described the mathwork behind orbital rendezvous in his thesis. Doesn't sound like a steel-eyed, cold-blooded superhero, huh?


Title: Re: P52 IMU Realign Apollo DSKY Error
Post by: jalexb88 on January 05, 2017, 02:13:56 PM
all those thing should be included in the checklist? is this really realistic? I mean does the astronauts this all this in that way? for me it looks more as a flying controller simulator than a space flight simulator, maybe I am wrong. Have you ever tried this:

https://www.indiegogo.com/projects/go-for-launch-mercury-vr-educational#/

you may download the free demo here:

https://dl.orangedox.com/r9vGCk0tbGhIEMTSDV

Is there any chance that Orbiter could be something like that?

I don't know for sure about that program but a lot of those other simulators don't use a real-time physics engine so it's more of a "scripted" experience which makes it easy to only simulate the "astronauts perspective" part. In orbiter/NASSP however, we must simulate the ground support portion because nothing is scripted, we are using real Newtonian physics and if you screw up your maneuver or alignment by a fraction you will miss the target by a large amount. in NASSP we must use either the MCC simulation (PADs and uplinks with the MCC menu) or using an MFD such as RTCC MFD to accomplish what the people on the ground did. Space flight is not a one-man affair like flying an airplane, its a whole team of people most of which are on the ground, the "flight controllers". In an ultra-realistic sim like orbiter, this must be simulated.