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Author Topic: LunarTransferMFD  (Read 9623 times)
jarmonik
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« on: February 19, 2009, 11:21:56 AM »

Hello,

I have just released an alpha version of LunarTransferMFD (LTMFD) for testing purposes. It's a fully numerical trajectory search MFD for both TransLunar and TransEarth trajectories with easy to use user interface and compatible with current IMFD IPC com inteface. There is a conflict between IMFD and LTMFD therefor they can not be active from the modules tab at the same time until the IMFD side of the problem is fixed.

Targeting accuracy of the TEI program is about 500 meters if measured in pericynthion altitude. It's more like a problem to execute the burn in the Orbiter as it was planned by the MFD. This still requires a lot of development and work.   

TLI program has following input paramaters:

PeT - Time of pericynthion (PC) passage
PeA - Altitude of pericynthion
EqI  - Inclination relative to equator at PC

Or alternatively:

PeT - Time of pericynthion (PC) passage
PeA - Altitude of pericynthion
Tgt  - Surface target site
TOA - Time of orbit alignment with target site

Under work:

PeT - Time of pericynthion (PC) passage
PeA - Altitude of pericynthion
Hed - Flight heading in the pericynthion


TEI program is using following set of targeting parameters:

PeT - Time of periapis (perigee) passage
PeA - Periapis altitude
Hed - Flight heading in the periapis passage

Or alternatively:

ReT - Time to reentry interface
ReA - Reantry angle
Hed - Flight heading in the reentry interface

Edit: http://koti.mbnet.fi/jarmonik/LTMFD_Alpha_1.zip

« Last Edit: February 19, 2009, 11:26:37 AM by jarmonik » Logged
jc121081
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« Reply #1 on: February 19, 2009, 11:26:21 AM »

Great news! Thanks Jarmo! I'll give it some testing right away! Thumbs Up
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Current Work:
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jalexb88
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« Reply #2 on: February 19, 2009, 06:14:38 PM »

Excellent!!!    Happy  Just tested it out.  Its very precise, I got to the moon at the exact target altitude and time. Now for the TEI...
Will there be P30 LVLH velocities in the final version?    And also, I was wondering if it would be possible to have an option for imperial units inside the MFD, for apollo missions.    Thanks for this great tool!!

Alex
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Tschachim
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« Reply #3 on: February 19, 2009, 06:48:19 PM »

And also, I was wondering if it would be possible to have an option for imperial units inside the MFD, for apollo missions.

As it's  compatible with current IMFD IPC com inteface, you should be able to request the burn data with PAMFD, which displays them in ft/s.

Cheers
Tschachim
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jc121081
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« Reply #4 on: February 19, 2009, 07:17:19 PM »

Well, maybe not yet. I just tried it with PAMFD and it's not accepting data yet from the other MFD, but I have to say that this new MFD is fantastic so far. It simplifies the whole process of having to manually iterate PeT/PeA and even makes it much easier for us to target lunar Pe Lat and Lon. If you try a TLI burn with it, it will have some difficulty orienting the SIVB (PAMFD would normally simplify this) but it gets it pretty close and the result is quite impressive. Happy
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Tschachim
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« Reply #5 on: February 20, 2009, 06:00:08 AM »

Well, maybe not yet. I just tried it with PAMFD and it's not accepting data yet from the other MFD...

Did you disable IMFD as mentioned by Jarmo?

If you try a TLI burn with it, it will have some difficulty orienting the SIVB (PAMFD would normally simplify this)...

Yes, the S-IVB is very hard to handle, but PAMFD/S-IVB IU should be able to execute LunarTransferMFD as precise as IMFD burns. Happy

Cheers
Tschachim
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jc121081
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« Reply #6 on: February 20, 2009, 11:44:13 AM »

Did you disable IMFD as mentioned by Jarmo?

Yes, I did. But in either case, it really works well in its initial state. I just tried it on a TLCC, TEI and TECC on a non-vAGC scenario and the results really are fantastic. Another major benefit I see with it is, if you go through the motions and compute the maneuver, there is an integrated Flight Monitor that renders the need for a second MFD (such as IMFD's Map program) to be open, or in the case of TEI, three MFD's.
« Last Edit: February 20, 2009, 11:47:34 AM by jc121081 » Logged



Current Work:
Overhaul of Ap8 vAGC FP, Wiki FP's

Future Work:
Ap14 Q FP, Ap15 Q FP, Ap16 Q FP, Ap17 Q FP
jarmonik
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« Reply #7 on: February 20, 2009, 02:43:13 PM »

Well, maybe not yet. I just tried it with PAMFD and it's not accepting data yet from the other MFD

I can confirm that it's not working, there was a small bug preventing data transfer, but it also leaded into a discovering even a greater problem. LTMFD doesn't have P30 compatibility mode as IMFD does. In current implementation burn data exists only in ecliptic J2000 frame of reference. So I have to implement data transfer to P30 Input frame. This task is actually related in the other topic we ware discussing in the other thread as well as into the External Delta V sheet.  I still need to study the External Delta V sheet as well as the method that IMFD was using for the frame conversion and search possible errors.

One possibility is the move the frame conversion code from the IMFD into PAMFD. In that case if there are any problems related in these conversions those could be fixed/addressed by anyone. 
But, of course, there are some things those can not be done outside of LTMFD or IMFD for an example conversions between rotating frames like delta velocity conversion from global ecliptic J2000 frame to a frame relative to immediate velocity vector of the vessel. Unless I am mistaking LVLH frame used in P30 is non-rotating frame.
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jarmonik
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« Reply #8 on: March 10, 2009, 03:00:40 PM »

Ok, Here is Alpha 2 http://koti.mbnet.fi/jarmonik/LTMFD_Alpha.zip
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jc121081
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« Reply #9 on: March 10, 2009, 03:32:33 PM »

Thanks Jarmo! Excellent work! Happy
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Overhaul of Ap8 vAGC FP, Wiki FP's

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Coussini
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« Reply #10 on: March 11, 2009, 09:31:09 PM »

Wow.... I did a test using LunarTRansferMFD.

I did a TLI, 2 X TLCC, the LOI (From IMFD Course Program - ORBIT INSERT) that's very easy and accurate...

I did also the TEI and 2 X TECC and a EOI (From IMFD Course Program - ORBIT INSERT)

I just understand that the LOI PGM in the MFD can be finish soon. That's probably the easy part for you Jarmonik.

Thank's Jarmonik for your great contribution in Orbiter. Without you... Orbiter should be lost in space Wink

« Last Edit: March 12, 2009, 11:54:23 AM by Coussini » Logged

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jarmonik
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« Reply #11 on: March 13, 2009, 08:49:36 PM »

I just understand that the LOI PGM in the MFD can be finish soon. That's probably the easy part for you Jarmonik.

It's not that easy. There has been some discussion about adding a periapis fine tune feature in the LOI program. I am not so sure how to do that but I am not expecting any troubles. But I am going to finish TLI and TEI programs before starting to work LOI program.

EDIT: Any ideas how important is the orientation of line of apsides ?  I suppose it can be controlled very well during orbit insertion in wide range. Of course, the range will also depend from orbit eccentricity.
« Last Edit: March 13, 2009, 09:17:45 PM by jarmonik » Logged
jalexb88
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« Reply #12 on: March 20, 2009, 10:46:23 PM »

Regarding the future LOI program would it be possible to also have plane fine-tuning so that we are well aligned with the target base?
In the real apollo LOI they had a bit of plane change velocity, my guess is to adjust the path over the landing target.
I see that PAMFD now reads LTMFD!!    Thumbs Up

Alex
« Last Edit: March 20, 2009, 11:59:33 PM by jalexb88 » Logged
Graham2001
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« Reply #13 on: March 21, 2009, 05:19:45 AM »

I've just tried out the Alpha2 version on my own installation and got an immediate CTD.

Unsure of the cause. Plan to check and then upload the orbiter logs just in case a clue is there.

Edit:I've tried using it with IMFD disabled as advised in the OP just in case that was the cause. I got exactly the same result.

Has that bug been fixed yet?

The orbiter logs did not give any clue as to what is happening.
« Last Edit: March 21, 2009, 08:21:56 AM by Graham2001 » Logged
jalexb88
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« Reply #14 on: March 21, 2009, 10:14:45 AM »

I also sometimes get a CTD, try playing around with the settings, I find most settings work, but a few give a CTD. I think if you set the TIg time to close to the present time it might give a CTD as well.

Alex
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