Meadville Space Center

Project Apollo - NASSP => Programming => Topic started by: Swatch on December 05, 2007, 12:42:58 AM



Title: IMFD 5.1 support/TLI burn
Post by: Swatch on December 05, 2007, 12:42:58 AM

PS: I also committed the new IMFD communication support including a new TLI burn for the SIVB I'm going to explain later, just in case someone wonders about all these changes just for new panel bitmaps...

It might just be me...but this IMFD stuff has broken my build environment.  I get unresolved externals.... is there any special configuration change or settings change that you did for this?


Title: Build problems
Post by: Tschachim on December 05, 2007, 04:43:49 AM
If you're using VS 2003 with our own project files, you need to re-convert them because of the new files, the VC6 and VS 2005 project files in CVS should be hopefully fine though...


Title: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 05, 2007, 06:13:52 AM
I finally finished the first version of the new IMFD 5.1 support, you need to update your Orbitersdk and Scenarios directory and install the latest IMFD 5.1 version from here: http://koti.mbnet.fi/jarmonik/Orbiter.html

The IMFD communication support introduces two new features:

The Saturn sends a couple of mission specific parameter like current GET, lunar landng site, TLI time etc. to IMFD, so less input in IMFD is required from the user in order to calculate a burn. All currently possible settings are explained here: http://nassp.sourceforge.net/wiki/Scenario_File_Options. In the "Apollo 11 Quickstart - Launch" scenario all parameters are set, help with the other scenarios would be greatly appreciated. :)

Also burn data (dV, time etc.) can be requested from IMFD, this is controlled by the ProjectApolloMFD. The TLI screen has been replaced by a new IMFD screen, which provides two functions. With the REQ button you can start and stop requesting burn data from IMFD. The values should be used with the VAGC P30, so the GET of ignition and dV in local vertical coordinates are displayed in ft/s. IMFD needs to be configured like this to send proper burn data:

* On the configuraton screen, set LambertAP Mode to ApolloP30
* The guidance mode needs to be "Off-Axis" (not "Realtime")   
* In the Delta Velocity program use "P30 LVLH" and "Off-Axis"

That means the burn is "non-impulsive" (i.e. not an instantaneous velocity change) and the spacecraft attitude remains constant w.r.t. the reference system during the burn, which is the way how VAGC P30 works. Bit I didn't test that with VAGC P30 neither for MCCs nor for LEO burns (Apollo 7) yet, so test results would be greatly appreciated. :)

With the SIVB button you can start the TLI burn, the simplest way to go to the Moon is now like this:

* Start the "Apollo 11 Quickstart - Launch" scenario
* Launch to LEO automatically as usual
* Open IMFD
* On the configuraton screen, set LambertAP Mode to ApolloP30
* Open the Course - Target Intercept program
* Switch guidance mode from Realtime to Off-Axis
* Play a little bit with TEj in order to minimize dV
* Open ProjectApolloMFD in a different MFD
* Press IMFD and then SIVB
* Wait until the burn is finished, do not close any of the MFDs until the burn started.
* If you do nothing, you'll crash into the Moon at about GET +75h...

ProjectApolloMFD will request burn data automatically and upload them to the S-IVB IU at 900s before ignition. Also, it will update the burn data periodically until the burn starts, because both attitude changes and the ullage thrusters change the orbit and so the burn data. The burn is executed the same way as the old ProjectApolloMFD TLI burn method, but isn't a simple prograde burn anymore but uses the IMFD burn data and works very similar to the VAGC P30 internally. Panel interaction (lights, TLI inhibits etc.), sounds, ullage thrustes, thrust build-up, thrust decay etc. are still the same. The only thing I needed to disable is the J-2 mixture ratio change ("PU-Shift") during the burn, because that changes thrust and ISP during the burn, which is something IMFD can't handle at the moment, but I'll try to talk with Jarmo about that.

Also, the Simple AGC P15 and the unmanned Apollo 4 and 6 missions should work as before (prograde burn), but I didn't test that very often, so there can be bugs.

Of course hitting the Moon is no realistic way to do a TLI, so if you want to achieve a proper free-return trajectory, calculate the burn by using the tutorial provided by Jarmo here: http://koti.mbnet.fi/jarmonik/IMFD5-Freereturn.zip (don't forget to set LambertAP Mode to ApolloP30) and execute the burn using ProjectApolloMFD as explained above. In my tests the resulting trajectory has still some inaccuracy, mainly because of the thrust build-up/decay, typically my periapsis altitude is off by about 50km.

That's all for now, I'm going to update the wiki according to that and probably improve the new features a little bit, test results, bug reports and suggestions are welcome as usual. :)

Many thanks to Jarmo for all the hard work with IMFD and the new communication interface and for the patience answering all my silly questions! :)

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: Coussini on December 05, 2007, 07:26:11 AM
Can you add here some screen shoot of the new Project Apollo MFD. Thanks.


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 05, 2007, 07:33:08 AM
Sure:


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on December 05, 2007, 08:46:54 AM
Just thought you all might like to know, I'm currently working on calculating proper free-return trajectories for apollo 14.  After I get that one, it should be easy enough to do the rest.  This is all with IMFD's offset using mostly trial and error.  I'm basing this on the table in the IMFD manual, and tweaking to work properly with our actual burns.  I'll let you know when I get something good...


Title: Re: IMFD 5.1 support/TLI burn
Post by: Coussini on December 05, 2007, 08:58:46 AM
Thanks Tschachim  :)


Title: Re: IMFD 5.1 support/TLI burn
Post by: FordPrefect on December 05, 2007, 10:09:10 AM
Great work Tschachim and jarmonik!  :ThumbsUp432:

@ lassombra, for what you intend to do, the following information quoted from Henry's space pages might be interesting to you:

Quote
Actually, it's impossible to fly anything but an equatorial orbit using a
free-return trajectory.  In fact, Apollo 11 was the last lunar mission to
use a pure free-return trajectory.  The "H" missions (12-14) started out
in free-return trajectories but shifted to non-return ones after S-IVB
separation and CSM-LM docking, with the shift done progressively earlier
in the later flights.  The "J" missions injected directly into non-return
trajectories, again getting increasingly aggressive about it as time went
by -- in the event of an SM engine failure, Apollo 15 could have moved
back to a free-return trajectory using its RCS thrusters, while Apollo 17
would have had trouble doing it even with the LM descent engine.


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 05, 2007, 10:29:45 AM
I mean to remember that Apollo 12 was the last free-return mission and Apollo 13 the first hybrid mission (i.e. shifting to non-returns during the flight), but I'm not sure...


Title: Re: IMFD 5.1 support/TLI burn
Post by: FordPrefect on December 05, 2007, 10:36:31 AM
Tschachim, I wanted to create a new quickstart launch scenario for Apollo 17, I have some question concerning a few parameters given in the new scenarion file. Sorry if these are silly. Anyway here goes:

Code:
  SIFUELMASS 2145798.0
  SIEMPTYMASS 131621.0
  SIIFUELMASS 442393.0
  SIIEMPTYMASS 39869.0
  S4FUELMASS 107072.0
  S4EMPTYMASS 12426.0
  ...
  SICSHUT 135.0
  SISHUT 161.63
  SIICSHUT 459.8
  SIIPUT 498.0
  SIISHUT 548.22

Are these values fixed (non variable) for Apollo 8, 10 to 17?

 
Code:
IGMST 204.1

What defines this parameter?

Code:
  TLIMJD 40418.677824
  LOIMJD 40421.723495
  FREERETURNPECMJD 40421.723495
  FREERETURNPECALT 250000

Are the MJD's given here relating to the (flight plan*) scheduled times for TLI, LOI, with FREERETURNPECMJD being always identical to the LOIMJD?
* According to the real world times, as given in e.g. at the "Apollo by the numbers" website

 
Code:
MOONMJD 40422.845833

What defines this value?

Code:
  EARTHEIMJD 40426.691042

This is the time of Trans-Earth-Injection, correct? *EDIT* No, it must be the time of Entry Interface..

Code:
  ATTACHSTATE 63

What's this needed for?

Thanks for your help! Eventually I would be willing to do the scenarios for the other missions as well, as soon as I figured your explanations.



Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 05, 2007, 10:56:36 AM
(Almost) everything is explained here: http://nassp.sf.net/wiki/Scenario_File_Options  :)

The Saturn masses/times are mission specific. The Apollo 11 values should provide a good starting point, but the J-missions are rather special, so I'm not sure.

The free return pericynthion MJD isn't necessary the same as LOIMJD, but both free return pericynthion settings aren't used by IMFD currently. MOONMJD is the MJD of the landing, this is used by IMFD's Map program to calculate/display the landing site alignment. EARTHEIMJD is the time the CM will reach entry interface, there's no TEIMJD at the moment.

ATTACHSTATE is something only Movieman knows, I didn't find it in wiki. I wonder if it's really necessary to have that in the launch scenarios or if it can be set to the launch defaults in the code if it's missing in the scenario...   :wink:

Cheers
Tschachim


Title: Re: Build problems
Post by: Swatch on December 05, 2007, 11:35:17 AM
If you're using VS 2003 with our own project files, you need to re-convert them because of the new files, the VC6 and VS 2005 project files in CVS should be hopefully fine though...

I actually didn't want to re-convert, so I figured out a way around.   If anyone else is using VS2003, just add the new IMFD files (in the IMFD folder) to the Saturn5NASP and Saturn1b projects.  *.cpp files into the Source folder, *.h files into the Header folder.  The only other person I know using this is dseagrav, but he knows the ins and outs of VS2003 better than I, so he probably already would know to do that.


Title: Re: IMFD 5.1 support/TLI burn
Post by: Coussini on December 05, 2007, 12:06:43 PM
Usualy, in the real mission.... what kind of procedure the Astronaut use. Are they use the DSKY for any TLI burn ????

The current Apollo MFD is use only with the Quickstart mode and standard mode only.

Thanks to any reply


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 05, 2007, 01:02:42 PM
It's not too bad from the realism point of view. The AGC (or DSKY) was used to monitor the burn only, even P15 just provides backup cutoff capability, no burn control. The real TLI was computed by the RTCC (Real-Time Computer Complex, see http://www-03.ibm.com/ibm/history/exhibits/space/space_realtime.html) and uploaded via telemetry to the Saturn IU (Instrument Unit), which executed the burn. So if you think of IMFD as the RTCC and ProjectApolloMFD as the MCC/telemetry (and the Saturn as the Saturn :) ), it's quite realistic for now, but will be beaten by the upcoming mission control stuff, of course: http://www.ibiblio.org/mscorbit/mscforum/index.php?topic=992.0

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: Christophe on December 05, 2007, 02:01:32 PM
Fantastic work Tschachim! :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on December 05, 2007, 02:55:42 PM
Yeah, I know about the hybrid trajectories and such.  I'm working on figuring out the easy numbers that can be just punched in to work with our project so that we can just put that in the docs.  The table given in the IMFD docs are specifically for AMSO but should be able to be easily adapted to what we're doing.  Most importantly, I am working to get the entry interface correct, as that seems to be the biggest problem for a free-return trajectory, I've been missing earth most every time.

What would be great is if we could force IMFD to use the numbers we come up with, but I don't know if that is possible?


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 05, 2007, 05:01:57 PM
Excellent new addition! Testing it now. I'll also try some MCC's and note the outcome.

***Ooops! Didn't realize the new MFD wasn't in yet  :roll: ***


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on December 05, 2007, 09:07:50 PM
It's in the CVS, if you can build your own beta modules pack.

I am waiting on a few things and then I'm going to build a new pack for distribution.


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 05, 2007, 09:46:44 PM
Ahhh, that'd explain it. Forgot PAMFD was part of the modules...  :oops:


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on December 05, 2007, 11:51:00 PM
jc, check your pm's


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 06, 2007, 07:00:57 AM
What would be great is if we could force IMFD to use the numbers we come up with, but I don't know if that is possible?

Do you mean the offset settings of the target intercept program? That's not covered by the current interface, but I can ask Jarmo about that.

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on December 06, 2007, 05:03:29 PM
Yeah, I'd like to be able to figure the right offsets and then put them into the scenario so that end users don't even have to know that.


Title: Re: IMFD 5.1 support/TLI burn
Post by: movieman on December 06, 2007, 05:05:20 PM
BTW, ATTACHSTATE and SLASTATE are documented now. Both should generally work OK with defaults, but they're wrong for some missions.


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 06, 2007, 10:33:55 PM
Decided to give testing on Apollo 7 a break for today and gave the new PAMFD a whirl using quickstart Apollo 11. I must say that it works very well!  :ThumbsUp432:

Here is my report:

The integration between IMFD 5.1 and the MFD worked very well aside from one thing (now this is something that only I noticed, and may not be the same for everyone else). After you hit the "SIVB" button on the MFD it displays "requesting" and then displays the velocites in fps similar to P30 (a GREAT feature, by the way), however, consulting to the procedure you posted, Tschachim, it says that the only button you need to hit is the "SIVB" button after you select "IMFD." After a little while, strangely, I noticed that the "requesting" status message on PAMFD disappeared. I remedied this by hitting the "REQ" button as you stated in the documentation, but was not listed in the procedure. It then remained in "requesting" status and did not stop acquiring burn data from IMFD from that point forward. This happened to me on several runs of the scenario, just to make sure it wasn't a "one-time" thing. Not that big a deal, just wanted others to know in case they have this particular problem.

The burn was excellent, with still a little fuel to spare in the SIVB. Later in the mission, I performed only one MCC (only using BaseApproach, and without relying on data from the map program) and it left me with a nice perigee of almost exactly 115nm at the time of the LOI burn. At the end of LOI2, I had around 34.5% SPS fuel remaining.

I decided to take the LEM down (my first time in a VERY long time doing this) and completed my very first "launch-to-lunar landing" in a single scenario. After a brief stay, I launched and rendezvoused with the CSM (if only it were this simple in Apollo 7!) and performed the TEI burn. At the end of the sequence of MCC's during the coast I had close to 5% SPS fuel remaining. Splashdown was flawless, within 2km of the landing site.

I am curious, however, of two things...

1. Are there plans in the future to possibly augment the acquisition of burn velocities into PAMFD from, perhaps, the BaseApproach program? (Could be beneficial to future vAGC lunar missions)

2. Is the problem between vAGC scenarios and compatibility with autoburn functions still an issue or has that now been resolved?

All in all I am very happy with these additions, and the new panels look fantastic! Can't wait to try out the new switches once they're wired so I can add their functions to the flightplan/procedures.  :wink: Keep up the great work!


Title: Re: IMFD 5.1 support/TLI burn
Post by: FordPrefect on December 06, 2007, 11:25:43 PM
Nice report, JC!

BTW do you remember the dV of your MCC? I am just curious how large/small it was (and therefore get an impression how precise IMFD 5.1 and the TLI burn is). Thanks!


Title: Re: IMFD 5.1 support/TLI burn
Post by: Coussini on December 07, 2007, 08:40:35 AM
Nice job jc121081  :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 07, 2007, 04:28:48 PM
BTW do you remember the dV of your MCC? I am just curious how large/small it was (and therefore get an impression how precise IMFD 5.1 and the TLI burn is). Thanks!

Sure! The dV for my lone pre-LOI MCC was (if I remember clearly) around 25m/s displayed on BaseApproach. As I mentioned, this sent me into a very stable periapsis of 115km. I should also mention that I waited until the CSM/LM stack was inside the lunar SOI before computing/performing the burn.

Hope this helps!


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 08, 2007, 12:38:22 PM
BTW, ATTACHSTATE and SLASTATE are documented now. Both should generally work OK with defaults, but they're wrong for some missions.

Thanks! So I assume 63 is the default value and we don't need it in Saturn 5 Moon landing scenarios (and can remove it from the Apollo 11 Quickstart scenario)?

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: movieman on December 08, 2007, 02:25:26 PM
I believe the defaults will work OK for the lunar landing missions.


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 10, 2007, 12:19:53 PM
Hi jc121081,

thanks for testing!

...After you hit the "SIVB" button on the MFD it displays "requesting" and then displays the velocites in fps similar to P30 (a GREAT feature, by the way), however, consulting to the procedure you posted, Tschachim, it says that the only button you need to hit is the "SIVB" button after you select "IMFD." After a little while, strangely, I noticed that the "requesting" status message on PAMFD disappeared...

That was somewhat intentional, but I already feared it would lead to some confusion, so I fixed it, the internal requests of the S-IVB burn program aren't displayed anymore.

1. Are there plans in the future to possibly augment the acquisition of burn velocities into PAMFD from, perhaps, the BaseApproach program? (Could be beneficial to future vAGC lunar missions)

I'm going to talk with Jarmo about the BaseApproach program.

2. Is the problem between vAGC scenarios and compatibility with autoburn functions still an issue or has that now been resolved?

This new ProjectApolloMFD S-IVB burn program should work with all modes (Quickstart, Standard and VAGC), no need to use IMFD's "native" autoburn program anymore (which isn't working very well with the S-IVB anyway, mainly because of the "non-CoG-centered" RCS).

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 10, 2007, 05:09:38 PM
Good stuff! Will be looking forward to it!  :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 11, 2007, 09:24:47 AM
I'm going to talk with Jarmo about the BaseApproach program.

I just committed a fix for that, so now you can use the REQ button to request burn data from the BaseApproach program, too.

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 11, 2007, 02:30:56 PM
Hello Everybody,

I was invited here by Tschachim and I must say that you have done very nice job with the NASSP. :) There was a guestion about the accuracy of the TLI. So far, I haven't been able to test the latest features of the NASSP but from my other experiences I can say that it should be possible to hit in a corridor of the +-15km in a Lunar orbit without MCCs. There is a known problem that the targeted peri-cynthion altitude will decrease about 15km during the TLI from unknown reason. This can be compensated by setting the initial altitude 15km higher than required. Usual the MCC (TEI+30h) has a magnitude less than 2 m/s. Except Apollos 12 and 14 where it is about 25m/s. This, of course, requires very good offset setups for both TLI and MCC.

Speaking about offsets I must mention that I am working a new program with auto-offset feature that would work fully in a numerical basis providing good targeting accuracy in every flight stage. So, the guessing of offsets should become obsolete. The new program would have the peri-cynthion state (PC-ALT, PC-MJD, PC-INC) as an input parameter or the perigee state during the TEI. I will keep you informed about the progress.

Jarmo

PS. Spell Check in a forum  :cool7777:


Title: Re: IMFD 5.1 support/TLI burn
Post by: FordPrefect on December 11, 2007, 05:46:33 PM
Hey Jarmo, great to see you here!  :)

Those new features sound terrific, I am looking forward to your news. I was hoping so much that one day we will be able to perform the TLI with such a precision that the deltaV for the MCC are similar to real world numbers, and as you mentioned you are on the way to make this possible. This is getting really exciting!

@JC, thanks for the numbers.


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 11, 2007, 06:07:50 PM
Welcome to the forum, Jarmo!

I would personally like to thank you for the work you have done not only for our project but for the entire Orbiter community in your fantastic IMFD. Great job, and good to see you here!

I just committed a fix for that, so now you can use the REQ button to request burn data from the BaseApproach program, too.

Thanks Tschachim, I'll give this some testing tonight.  :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: Coussini on December 11, 2007, 07:53:54 PM
Can you explain the Apollo MFD procedure with the IMFD.

I know how use the IMFD alone (Course and Map program)..., but should i have a new scenario to test that. Can you give me a testing case, because i would like to test it. Should i use the new IMFD 5.1B

That's important for me to undestand what kind of procedure to use, the step, to reflect the next exemple.



Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 12, 2007, 09:46:27 AM
Hi Coussini,

Can you explain the Apollo MFD procedure with the IMFD.
...
Should i use the new IMFD 5.1B

Yes, you need to use IMFD 5.1. From my first post:  :)

* Start the "Apollo 11 Quickstart - Launch" scenario
* Launch to LEO automatically as usual
* Open IMFD
* On the configuraton screen, set LambertAP Mode to ApolloP30
* Open the Course - Target Intercept program
* Switch guidance mode from Realtime to Off-Axis
* Play a little bit with TEj in order to minimize dV
* Open ProjectApolloMFD in a different MFD
* Press IMFD and then SIVB
* Wait until the burn is finished, do not close any of the MFDs until the burn started.
* If you do nothing, you'll crash into the Moon at about GET +75h...

Feel free to ask if I should elabortate a step, sooner or later I'll update the wiki, too. If you want to setup a proper trajectory, use this tutorial provided by Jarmo: http://koti.mbnet.fi/jarmonik/IMFD5-Freereturn.zip

Cheers
Tschachim



Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 12, 2007, 10:20:41 AM
Hi Jarmo,

welcome to the Meadville forum!  :)

So far, I haven't been able to test the latest features of the NASSP but from my other experiences I can say that it should be possible to hit in a corridor of the +-15km in a Lunar orbit without MCCs.

That's better than what I was able to achieve yet, with the latest version I have a "runtime error" (i.e. I calculate the burn, save the scenario and then do the burn several times without changing anything in IMFD and look at the resulting PeA) of about +/- 25km. I didn't stop thinking about how to improve that, but given that a change of 0.01s in ignition time (there's an "empirical calibration" to compensate the ullage thrust and thrust build-up I played a lot with) changes the resulting PeA for about 15km and my average time step length is about 0.01s, the +/- 15 km you mentioned is probably the best possible result.

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: Christophe on December 12, 2007, 10:34:09 AM
Hi Jarmo!
Very glad to see you here. :)
And thanks so much for your great great great addon, and the work you did especially for NASSP.  :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: Coussini on December 12, 2007, 12:16:28 PM
Hi Coussini,

Can you explain the Apollo MFD procedure with the IMFD.
...
Should i use the new IMFD 5.1B

Yes, you need to use IMFD 5.1. From my first post:  :)

* Start the "Apollo 11 Quickstart - Launch" scenario
* Launch to LEO automatically as usual
* Open IMFD
* On the configuraton screen, set LambertAP Mode to ApolloP30
* Open the Course - Target Intercept program
* Switch guidance mode from Realtime to Off-Axis
* Play a little bit with TEj in order to minimize dV
* Open ProjectApolloMFD in a different MFD
* Press IMFD and then SIVB
* Wait until the burn is finished, do not close any of the MFDs until the burn started.
* If you do nothing, you'll crash into the Moon at about GET +75h...

Feel free to ask if I should elabortate a step, sooner or later I'll update the wiki, too. If you want to setup a proper trajectory, use this tutorial provided by Jarmo: http://koti.mbnet.fi/jarmonik/IMFD5-Freereturn.zip

Cheers
Tschachim


Thanks  :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 12, 2007, 04:38:38 PM
Hi Jarmo!
Very glad to see you here. :)
And thanks so much for your great great great addon, and the work you did especially for NASSP.  :ThumbsUp432:

It's really Tschachim who did the work.

Well, I did some test flight with the latest NASSP with not much success. It looks like there has been a lot of progress. The main panel has a lot more buttons than before and it's not just a main panel anymore. I tested the Apollo 11 quick start scenario and I was able to kill the crew in oxygen poisoning and didn't get out of ground.  :oops:  Really, not for newbies like me.  Looks like I gotta start by reading the manual and check lists.  I also tried LOI with ApolloMFD, it did got the data from imfd but didn't engage the engine. I suppose I need to start a fuel pumps etc..

Also I suppose the new panels are too much for my old GeForce FX5200 I got only 17fps and about 100fps in glass cockpit view but this is not really a problem.  But there is something odd when increasing the time acceleration from 100x to 1000x the frame rate will drop from 100 to 12. At first I thought that this could be caused by simulation of the vessel functions but I am not so sure anymore. 


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 12, 2007, 06:10:37 PM
I made a successful TLI test and everything seems to be OK.  182km was targeted before TLI and 108km was the actual altitude after TLI.  There are 3 issues those are missing from the IMFD programming and will most likely reduce accuracy.

1. RCS firing before S-IVB ignition is not included in calculations.
2. Delta-velocity that is gained during LM docking and separation.
3. PU (Propellant Utilization) problem.


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 12, 2007, 06:37:26 PM
Hi Jarmo,

I'm happy that you figured out how to launch, Project Apollo is quite complicated meantime. I suggest to use the Quickstart Mode for now, the wiki helps a little bit hopefully: http://nassp.sf.net

To compensate the ullage thrust (RCS firing) before the burn, the last burn data transfer from IMFD (running the target intercept program) is just 2s before the burn, the ullage thrusters are already off again, that seems to work fine. Also the PU-Shift is disabled for now.

But I just found another problem, it looks like I can upload a more precise version soon...

EDIT:
Also I suppose the new panels are too much for my old GeForce FX5200 I got only 17fps...

Try low resolution meshes and split panels: http://nassp.sf.net/wiki/Launchpad_Configuration_Options

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 13, 2007, 06:10:47 AM
But I just found another problem, it looks like I can upload a more precise version soon...

I found and fixed an inaccuracy in the burn timing, the TLI burn should be now working within the limits Jarmo mentioned (+/- 15km in PeA).

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on December 13, 2007, 09:40:49 AM
That's great news Tschachim.

Looks like this next beta modules pack is going to be a serious features release  :)


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 13, 2007, 03:55:34 PM
I found and fixed an inaccuracy in the burn timing, the TLI burn should be now working within the limits Jarmo mentioned (+/- 15km in PeA).
Cheers
Tschachim

I don't know what you did but it's just perfect now. Congratulations Tschachim.

Here is my test configuration http://koti.mbnet.fi/jarmonik/A11TLI.scn

Ignition: 02:45:08
Offsets:  Lon -1.9,  Lat 6.2  Rad 9.324M

Just open ApolloMFD over the Map program.  I ended up 12km higher orbit than targeted 140km. Also I suppose it is important that the flight data is transfered into ApolloMFD under 1x time acceleration. There is unknown anomaly that will effect into a dV calculations under acceleration.

Jarmo


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 14, 2007, 02:32:22 AM
Hi,

I have done some more testing with NASSP and latest beta of Orbiter.  NASSP will build, link and run OK (at-least visuals). Only problem that I was able to detect is related in ApolloMFD/IMFD/SIVB program that goes dead after pressing SIVB button. It doesn't show any status information or errors. Also it's not possible to reset and restart SIVB program. (Status is IDLE before pressing SIVB)The other program, using the REQ button, seems to work fine. (Of course, this problem doesn't happen under 2006 release)

Also the anomaly that I mentioned earlier occurs only when the attitude control is active (attitude keeping) also it is somehow related in gravity-gradient torque. Also it will occur sameway under IMFD attitude control as well as NASSP attitude control. But why it is depended about time acceleration.


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on December 14, 2007, 09:31:54 AM
Hi Jarmo,

thanks for your kind words!

Also I suppose it is important that the flight data is transfered into ApolloMFD under 1x time acceleration.

Yes, especially the last transfer 2s before the burn starts, but also while any engine is running (J-2 or APS). The S-IVB automatically sets the time acceleration to 1 at 9:38 minutes before ignition and changes it's attitude to the burn attitude. After the attitude is stable I typically switch to time acceleration 10x and wait for the 2nd automatic switching to time acceleration 1x at about 100s before the burn. Shortly after that the ullage thrust starts and I do not use time acceleration until the burn is finished.

I have done some more testing with NASSP and latest beta of Orbiter.  NASSP will build, link and run OK (at-least visuals).

Wow, thanks for testing, last time I tried (it's a while ago) it was crashing all over the place because of not-yet implemented animation functions in the beta, looks like I should try again sometime...

Only problem that I was able to detect is related in ApolloMFD/IMFD/SIVB program that goes dead after pressing SIVB button. It doesn't show any status information or errors...

No clue, I'd need to debug that, perhaps just another beta bug...

Also the anomaly that I mentioned earlier occurs only when the attitude control is active (attitude keeping) also it is somehow related in gravity-gradient torque. Also it will occur sameway under IMFD attitude control as well as NASSP attitude control. But why it is depended about time acceleration.

Do you refer to the "time acceleration affects dV calculations" anomaly from your last post? With the S-IVB any attitude change (and also station keeping against gravity-gradient torque) has a quite huge translational component because of the "non-CoG centered" APS (= S-IVB RCS) and this effect is bigger with time acceleration because of the longer time steps, which cause bigger thruster settings. But this is S-IVB specific, of course and shouldn't happen with the Delta Glider for example, I'm not sure if that is related to the anomaly...

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 15, 2007, 03:34:02 AM
Do you refer to the "time acceleration affects dV calculations" anomaly from your last post? With the S-IVB any attitude change (and also station keeping against gravity-gradient torque) has a quite huge translational component because of the "non-CoG centered" APS (= S-IVB RCS) and this effect is bigger with time acceleration because of the longer time steps, which cause bigger thruster settings. But this is S-IVB specific, of course and shouldn't happen with the Delta Glider for example, I'm not sure if that is related to the anomaly...

Actually Yes, And I think I was able to solve it.  There was a trigger that caused to abort and restart some calculations when the vessel had lost some mass (any mass).


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 15, 2007, 09:37:49 AM
Here is a quick procedure to perform TLI in Apollo 8 vAGC scenario using the IMFD/PAMFD combo that I'm going to include in the next flightplan I'm composing. Even with historical times, it works like a charm.  :ThumbsUp432:

Open Interplanetary MFD
Click "MNU"
Click "MOD" (Configuration)
Click "NXT" until "LambertAP Mode" is selected
Click "+" to select "Apollo P30"
Click "MNU"
Click the "Course" button
Ensure "Target Intercept" is highlighted and click "Set"
Click "NXT" until "Realtime" is highlighted
Click "+" to select "Off-Axis"
Click "PRV" until "TEj" is highlighted
Click "+" or "-" to change the Tej to "GET 2:50:37" and use "Adj" to change the increments as necessary
Click "NXT" until "TIn" is highlighted
Click "+" or "-" to change the TIn to "GET 69:08:20" and use "Adj" to change the increments as necessary
*If you started the scenario from pre-launch, you may need to add 3 hours to the TEj and TIn times
Open ProjectApollo MFD
Click "IMFD"
Click "SIVB"

Regards,
jc121081


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 15, 2007, 09:59:28 AM
Here is a quick procedure to perform TLI in Apollo 8 vAGC scenario using the IMFD/PAMFD combo that I'm going to include in the next flightplan I'm composing. Even with historical times, it works like a charm.  :ThumbsUp432:

It's great to hear that it works in vAGC scenarios as well. :)

Here is unofficial beta of IMFD: http://koti.mbnet.fi/jarmonik/IMFD51c.zip


Title: Re: IMFD 5.1 support/TLI burn
Post by: Coussini on December 15, 2007, 10:48:43 AM
Great news Jarmonik, thanks so much  :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: jc121081 on December 15, 2007, 12:50:04 PM
I like the offset procedure you included. Good job, Jarmo! :ThumbsUp432:


Title: Re: IMFD 5.1 support/TLI burn
Post by: jarmonik on December 15, 2007, 08:03:47 PM
It looks like there are a great failures in 5.1c so I have uploaded 5.1d to fix them.

http://koti.mbnet.fi/jarmonik/Orbiter.html


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on December 16, 2007, 12:34:33 AM
Alright, I've committed a slight bugfix/improvement to the Apollo MFD.  It is now capable of extracting the Mission Time through the Crawler Transporter.  It doesn't do anything else in that state obviously.  The other major change is one that had the potential to cause a CTD in the, admittedly unlikely (but still happened to me), event that someone hit the sequence of buttons to trigger a TLI burn program while focused on another vessel.

To fix it, I simply completely disabled the buttons and keys when not on the Saturn.


Title: Re: IMFD 5.1 support/TLI burn
Post by: nickel on January 04, 2008, 08:42:22 AM
Hello together!  :)
Am new here and I have real problems with the IMFD 5.1 clearly.
I would like to work with the IMFD 5.1.
But I dont know to what steps I need to keep on mercur for example, mars or Venus fly.
I have already tried a number of tutorials, unfortunately with not much success. To fly to the moon, it worked. But on other planets, unfortunately, not yet.  :oops:

I hope someone can help me and tell me what steps I must be respected so that it works.

Greeting  :)


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on April 13, 2008, 05:15:34 PM
With my last CVS commit I also updated the IMFD interface to support the latest version, IMFD 5.1g. The TLI burn now works like this:

* Start the "Apollo 11 Quickstart - Launch" scenario
* Launch to LEO automatically as usual
* Open IMFD
* Press MNU and open the Course - Target Intercept program
* Open ProjectApolloMFD in a different MFD
* Press IMFD and then SIVB
* Wait until the burn is finished, do not close any of the MFDs until the burn started.
* You'll arrive over the landing site in a periapsis altitude of about 100 km at the Moon at about GET +75h.

That's all, I don't get it more easy.  :)

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: lassombra on April 13, 2008, 10:14:24 PM
this is great news tschachim...  I am curious how you managed to automate the whole thing (so that when I get back to working on the quickstart to the moon checklist, I can implement this feature for other missions as well).


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on April 14, 2008, 07:38:06 AM
I am curious how you managed to automate the whole thing (so that when I get back to working on the quickstart to the moon checklist, I can implement this feature for other missions as well).

Yeah, that's the point actually, all that is based on a bunch of settings in the scenario, which are transferred to IMFD: http://nassp.sourceforge.net/wiki/Scenario_File_Options#Mission_parameter_options

For the offset configuration I calculated proper values with IMFD for Apollo 11 and put them to the scenario, so this is something which needs to be done by a developer mission per mission...

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: bluespace88 on April 14, 2008, 07:46:00 AM
so this was a feature that IMFD included and only needed extra lines in the scenario file?


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on April 14, 2008, 07:51:48 AM
Yes, we transfer these settings to IMFD and get the burn data back, which are used by the S-IVB to execute the burn.

Cheers
Tschachim


Title: Re: IMFD 5.1 support/TLI burn
Post by: Wailer on June 03, 2008, 09:43:24 AM
So this will work with the other scenarios other than Apollo 11?

Amazing feature! :D  I should copy this thread to the folks working on the current-day Ares/Direct/CEV add-ons to see if they could incorporate some of these ingenious features.

Fantastic job, gentlemen!

Cheers,


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on June 03, 2008, 10:21:32 AM
So this will work with the other scenarios other than Apollo 11?

Yes, it should (I didn't test it), but as mentioned in this thread you need to configure IMFD manually if you're not using the Apollo 11 Quickstart scenario.

Amazing feature! :D  I should copy this thread to the folks working on the current-day Ares/Direct/CEV add-ons to see if they could incorporate some of these ingenious features.

Go ahead!  :)


Title: Re: IMFD 5.1 support/TLI burn
Post by: Wailer on June 03, 2008, 01:19:58 PM
Ok, at the risk of sounding like an idiot, do you mean that I'd have to set up IMFD to

a) Use GET rather than MJD time calculations, and
b) Set up the Lambert solver to use Apollo P30?

Cheers


Title: Re: IMFD 5.1 support/TLI burn
Post by: Tschachim on June 04, 2008, 07:55:15 AM
 :D No idiocy here, you need to know IMFD fairly well to be able to ask questions like this...

The answer is No and No, both the GET and the ApolloP30 mode are set anyway. But all the settings defining the TLI burn are missing (TLIMJD, LOIMJD etc., see all settings here denoted with a [1]: http://nassp.sf.net/wiki/Scenario_File_Options#Mission_parameter_options), so you need to set up the actual TLI burn (times, offsets) manually.

Cheers
Tschachim