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Author Topic: IMFD 5.1 support/TLI burn  (Read 27055 times)
jc121081
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« Reply #30 on: December 10, 2007, 05:09:38 PM »

Good stuff! Will be looking forward to it!  Thumbs Up
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Tschachim
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« Reply #31 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
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jarmonik
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« Reply #32 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. Happy 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  Cool
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FordPrefect
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« Reply #33 on: December 11, 2007, 05:46:33 PM »

Hey Jarmo, great to see you here!  Happy

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.
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My Project Apollo work in progress:
* New detailed Lunar Module Ascent stage with virtual cockpit (VC currently planned as eye candy only) 18 % done

My Project Apollo work to be continued:
* new Service Module SPS engine bell
* various Saturn V textures, exhaust textures
* SIM Bay for the SM


My long-term plans are to create a:
* New detailed Lunar Module descent stage (eventually models of all flown LM's)
* New F-1 engines for the S-1C stage showing the foil (batting) insulation
* New LUT and launch pad (if nobody else does it)
jc121081
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« Reply #34 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.  Thumbs Up
« Last Edit: December 11, 2007, 06:17:18 PM by jc121081 » Logged
Coussini
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« Reply #35 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.



* PAMFDandIMFD.jpg (57.02 KB, 728x301 - viewed 268 times.)
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Tschachim
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« Reply #36 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:  Happy

* 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

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Tschachim
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« Reply #37 on: December 12, 2007, 10:20:41 AM »

Hi Jarmo,

welcome to the Meadville forum!  Happy

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
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Christophe
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« Reply #38 on: December 12, 2007, 10:34:09 AM »

Hi Jarmo!
Very glad to see you here. Happy
And thanks so much for your great great great addon, and the work you did especially for NASSP.  Thumbs Up
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Coussini
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« Reply #39 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:  Happy

* 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  Thumbs Up
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jarmonik
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« Reply #40 on: December 12, 2007, 04:38:38 PM »

Hi Jarmo!
Very glad to see you here. Happy
And thanks so much for your great great great addon, and the work you did especially for NASSP.  Thumbs Up

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.  Embarassed  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. 
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jarmonik
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« Reply #41 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.
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Tschachim
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« Reply #42 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
« Last Edit: December 12, 2007, 06:41:16 PM by Tschachim » Logged

Tschachim
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« Reply #43 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
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lassombra
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« Reply #44 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  Happy
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My current Project Apollo work:

Quickstart to the Moon initiative (Quickstart_to_the_Moon): Done through earth orbit.  Working on new method of calculating TLI.

Checklist Controller: 
  • MFD Interface 99%(Minor cleanup and future features remain)
  • Panel Interface 99%
  • Excel interface and logic 99%
  • LEM Event code.0%
  • DSKY Interface code. Framework complete, creating "buttons"
  Approximately 80% done. (Checklist Controller
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