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Project Apollo - NASSP 6.4.3 released!
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Author Topic: IMFD 5.1 support/TLI burn  (Read 26873 times)
Swatch
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jasonims
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« 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?
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My Project Apollo Work:
CM Visual
 -VC (~75% complete: texture work beginning again; mesh-78%; texture-70%)
Propulsion Particle Improvements (Focused on S1B right now, BETA 1.0 has been commited)
New Docking Method (~50% complete: research complete; coding partially completed, testing not underway)

Future Work:  (if it's here, it's deemed unnecessary to upcoming release)

Older Work:  (if it's here, it's fair game to whoever wants to improve)
EMS Implementation (committed: minor flaws, but groundwork is there, needs extensive testing)
EMS scrolls (committed: not refined, but usable)
SM Visual (committed: mesh-finished, texture-60%; possibly revisited in future)
J2 Texture (commited: room for improvement)
LRV (committed: mesh-finished, texture-90%; in future a ground up rebuild may be in order, but not on my plans)
Tschachim
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« Reply #1 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...
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Tschachim
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« Reply #2 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. Happy

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. Happy

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. Happy

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! Happy

Cheers
Tschachim
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Coussini
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« Reply #3 on: December 05, 2007, 07:26:11 AM »

Can you add here some screen shoot of the new Project Apollo MFD. Thanks.
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Tschachim
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« Reply #4 on: December 05, 2007, 07:33:08 AM »

Sure:


* PAMFDandIMFD.jpg (57.02 KB, 728x301 - viewed 487 times.)
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lassombra
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« Reply #5 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...
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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
Coussini
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« Reply #6 on: December 05, 2007, 08:58:46 AM »

Thanks Tschachim  Happy
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FordPrefect
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« Reply #7 on: December 05, 2007, 10:09:10 AM »

Great work Tschachim and jarmonik!  Thumbs Up

@ 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.
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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)
Tschachim
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« Reply #8 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...
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FordPrefect
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« Reply #9 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.

« Last Edit: December 05, 2007, 10:47:48 AM by FordPrefect » Logged

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)
Tschachim
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« Reply #10 on: December 05, 2007, 10:56:36 AM »

(Almost) everything is explained here: http://nassp.sf.net/wiki/Scenario_File_Options  Happy

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
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Swatch
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jasonims
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« Reply #11 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.
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My Project Apollo Work:
CM Visual
 -VC (~75% complete: texture work beginning again; mesh-78%; texture-70%)
Propulsion Particle Improvements (Focused on S1B right now, BETA 1.0 has been commited)
New Docking Method (~50% complete: research complete; coding partially completed, testing not underway)

Future Work:  (if it's here, it's deemed unnecessary to upcoming release)

Older Work:  (if it's here, it's fair game to whoever wants to improve)
EMS Implementation (committed: minor flaws, but groundwork is there, needs extensive testing)
EMS scrolls (committed: not refined, but usable)
SM Visual (committed: mesh-finished, texture-60%; possibly revisited in future)
J2 Texture (commited: room for improvement)
LRV (committed: mesh-finished, texture-90%; in future a ground up rebuild may be in order, but not on my plans)
Coussini
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« Reply #12 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 Huh?

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

Thanks to any reply
« Last Edit: December 05, 2007, 12:10:52 PM by Coussini » Logged

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Tschachim
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« Reply #13 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 Happy ), 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
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Christophe
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« Reply #14 on: December 05, 2007, 02:01:32 PM »

Fantastic work Tschachim! Thumbs Up
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