Project IMFD full manual

[Tommy]

For a basic Moon - Mars via Earth trip, open Target Intercept. In order, change Ref to Sun, src to Earth, and TGT to Mars. Set up the transfer the same as you would if leaving from Earth. Once you have that, open Slingshot, and set reference to Earth. Course should already be selected so there shouldn't be much else to do here except match the PeT to the PeT shown in Slingshot. Then open Orbit Eject and change Higher Orbit to Slingshot. I think you know how to go from there.

 

[markl316]

For a basic Moon - Mars via Earth trip, open Target Intercept. In order, change Ref to Sun, src to Earth, and TGT to Mars. Set up the transfer the same as you would if leaving from Earth. Once you have that, open Slingshot, and set reference to Earth. Course should already be selected so there shouldn't be much else to do here except match the PeT to the PeT shown in Slingshot. Then open Orbit Eject and change Higher Orbit to Slingshot. I think you know how to go from there.

Thanks. That was actually pretty easy, and it was MUCH more fuel efficient than an Earth to Mars transfer. That tutorial is going in.

 

[Usonian]

Nobody is interested in anything? Judging by the numerous questions and complaints about IMFD in the MFD Help/Questions forum, I would think people would be showing a little more interest. There's gotta be something that somebody would like to see in my manual/tutorial set.

I just ran across this thread and let me join in by saying, OUTSTANDING!!

I have been waiting for years to see a comprehensive, detailed IMFD "how to" manual, rendered in readable English. I don't mean to criticize jarmonik, he is clearly way smarter than me, but the English in his manuals is pretty badly broken. He also takes an engineer's approach to explaining his work, assuming the user has something like his level of background knowledge.

I am particularly interested in the Slingshot program. I have never seen an adequate explanation or tutorial for this.

As for "Why" versus "How" I am glad to hear you will attempt to address both questions. (No doubt, this approach is helping balloon your manual to 50+ pages!) The illustrations of planer and off-plane transfer orbits in jarmonik's v4.2 manual are particularly informative. I recommend borrowing them for your manual (click thumbnail).

I can hardly wait to see this. Cheers to Markl316!

 

[markl316]

For a basic Moon - Mars via Earth trip, open Target Intercept. In order, change Ref to Sun, src to Earth, and TGT to Mars. Set up the transfer the same as you would if leaving from Earth. Once you have that, open Slingshot, and set reference to Earth. Course should already be selected so there shouldn't be much else to do here except match the PeT to the PeT shown in Slingshot. Then open Orbit Eject and change Higher Orbit to Slingshot. I think you know how to go from there.

Hey, also, is it normal to have a large correction burn after leaving the moon's SOI (about 1500 m/s of dV in the slingshot program)?

---------- Post added at 03:26 PM ---------- Previous post was at 03:21 PM ----------

I recommend borrowing them for your manual (click thumbnail).

Good idea. I had actually put in the ones from the 5.0 manual but those look better, thanks.

 

[Kveldulf]

Hey, also, is it normal to have a large correction burn after leaving the moon's SOI (about 1500 m/s of dV in the slingshot program)?

I would assume that its normal, simply because you have to eject into the slingshot plan, rather then just modifying your trajectory like the IMFD Slingshot program is designed to do.

However, I am only speculating. Unfortunately, I'm unable to confirm this right now.

 

[Tommy]

Hey, also, is it normal to have a large correction burn after leaving the moon's SOI (about 1500 m/s of dV in the slingshot program)?

I'm not entirely sure, I've never done that kind of sling entirely by IMFD before. In fact, before last night I'd never tried a Moon-Earth-Other Planet sling. I did a Titan-Saturn-Mars trip back in about '05, but instead of using Orbit Eject with IMFD, I plotted the sling, then manually made a Hohman Transfer to Saturn with my Pe in the same place as the Pe in slingshot. Then I used Slingshot's AB at the Pe. I tried something similar last night, but after plotting the sling, I used Planet Approach in a non-shared IMFD to set up the Hohman transfer to earth, trying to get the PeA and PeT to match. Missed by a bit, and that caused some trouble with the sling's accuracy. I also had a fairly large course correction just after leaving the Moon. It's possible that the DV needed to escape the Moon is more than the velocity needed to transfer down to earth. If I can find some time this weekend I'll experiment some more and try to figure it out. There were some other errors I made that could account for it also, but the big correction called for by Planet Approach was towards the moon, which indicates either the Ejection angle was wrong, or ejecting gave me too much DV for the transfer.

 

[markl316]

Thanks, Tommy. Yeah I never understood what you meant by matching PeT and PeA, I just set the Earth to Mars Transfer, opened the Slingshot Program and time warped until dV hit a minimum, then took off at 90 degrees, did an orbit eject (getting data from slingshot). Once free of the Moon's SOI I hit Autoburn on the Slingshot Program (this was the HUGE burn, sometimes as high as 2500 m/s of dV). Then I just passed the Earth with no burn at periapsis and was on my way. Why do you do your burn at Periapsis? Isn't dV much greater than when you are far from a planet? Also, can I include Home Direct as one of the tutorials, giving you credit of course?

Good news--the manual is done. A bit of proofreading to do, but content wise it is done. Here is the table of contents (sorry for the big post):




Interplanetary MFD Background Information
Start Key Selection
Color Configuration
Setting Values from the Keyboard
Sharing Flight Plans
3D Rotation
Time in GET and UT
What is EIn?
What is RIn?
Information Flow
LambertAP Mode
Sources, Targets, and References
Burn Guidance
Burn Integrations
Burn Timing
Burn Guidance Modes
Burn Vector View
IMFD Configuration Page
Map Program
General Information
Button Layouts/Descriptions
Map Configuration Page
Text Modes
Map Program Displays
Course Programs
General Information
Target Intercept Program
General Information
Burn Guidance Modes
Transfer Types
Button Layouts/Descriptions
Target Intercept Program Displays
Offsetting the Target
Tangential Transfer Program
General Information
Tangential Transfer Program Display
Text Items
Planet Approach Program
General Information
Planet Approach Program Display
Text Items
Orbit Insert Program
General Information
Orbit Insert Program Display
Delta Velocity Program
General Information
Delta Velocity Program Display
Text Items
Orbital Program
General Information
Button Layout
Circularize Orbit Mode
Match Velocity Mode
Find Target Mode
Surface Launch Program
General Information
Button Layout
Surface Launch Program Display
Text Items
Orbit Eject Program
General Information
Orbit Eject Program Display
Text Items
Base Approach Program
General Information
Orbit Insert Mode
Reentry Mode
Slingshot Program
General Information
Slingshot Program Display
Slingshot Program Text
Appendix A: Glossary for Acronyms used in IMFD
Appendix B: Keyboard Commands
Appendix C: Common Flight Source, Reference, and Target Settings
Appendix D: Summary of Programs, When to use each Program, Helpful Hints about each Program
Appendix E: Navigation Maneuver Checklists


EDIT: This represents the first half of the project--the manual. Now I am going to create about 8 playbacks with in flight notes and a corresponding written tutorial with pictures describing what is being done in the playbacks in greater detail. To check out what each of these playbacks and written tutorials is going to be like, check out Home Direct at Orbithangar:
http://orbithangar.com/searchid.php?ID=3660

 

[Kaito]

I love you

 

[jedidia]

Seriously, this got to be a milestone. Maybe I'll be able to use IMFD after all, I NEVER could figure out how to use it properly. Just the moment before I was doing another attemp. Set up a trajectory to Mars, went into Orbit eject and started the programm. It looked all well, until about halfway out of the earths SOI, where the programm decided to cancel the burn, turn nearly retrograde, start to burn again and smash me back on full thrust into the atlantic ocean with a velocity of about 30'000 m/s. I still have no idea what the hell I'm doing wrong...

Ironically, shortly before impact I heard the "you're clear to land"... I think David Bowman must have felt similiar when his onboard computer tried to kill him... :dry:

 

[Usonian]

... It looked all well, until about halfway out of the earths SOI, where the programm decided to cancel the burn, turn nearly retrograde, start to burn again and smash me back on full thrust into the atlantic ocean with a velocity of about 30'000 m/s... :dry:

This sounds a lot like some other complaints/comments. There may be a serious bug in V5.xx -- Jarmonik says as much in the middle of this thread:

http://www.orbiter-forum.com/showthread.php?t=8336

There is a related discussion at this thread (although you will have to endure a pretty childish, unconstructive opening post):

http://orbiter-forum.com/showthread.php?p=107465#post107465

So, markl, what's your experience? Do you have problems with 5.xx? I assume you are running IMFD pretty hard, all over the solar system, to test your manual.

This has got me worried. I have been waiting a long time for a good IMFD manual.

 

[markl316]

This sounds a lot like some other complaints/comments. There may be a serious bug in V5.xx -- Jarmonik says as much in the middle of this thread:

http://www.orbiter-forum.com/showthread.php?t=8336

There is a related discussion at this thread (although you will have to endure a pretty childish, unconstructive opening post):

http://orbiter-forum.com/showthread.php?p=107465#post107465

So, markl, what's your experience? Do you have problems with 5.xx? I assume you are running IMFD pretty hard, all over the solar system, to test your manual.

This has got me worried. I have been waiting a long time for a good IMFD manual.

I have been running IMFD 5.3 a LOT, all over the solar system, doing many various complex flight maneuvers (planar transfers between Jovian Moons, Earth to Moon direct ascent, Moon to Mars with a slingshot around Earth, Mars to Phobos, Earth to Neptune Off-Plane Transfer, Earth to Saturn with a slingshot around Jupiter, Direct Reentry returning from the Moon to the Earth), and have had zero problems. The worst that will happen is that Autoburn will turn the wrong direction, so I will have to cancel it, wait about a minute, then engage it again and it works just fine. For the first thread you posted, Tangetal Transfer is VERY hard to get a perfect launch date, so I do NOT recommend ever using it. Important to note is that I have been using IMFD on Windows XP home edition. The only thing is though that for Orbit Insert, I use IMFD 4.2.1 (I have 4.2.1 and 5.3 installed) because Orbit Insert in 5.xx does not work well at all. I will begin running tests on my new laptop (Asus G51 with Vista) to see what happens.

jedidia, were you using XP or Vista? Honestly I don't think Vista is an issue, but then again I have never tried it on Vista, so I'll do that today and see.

During your Autoburn did you switch from external view to internal view or vice versa? That is very bad, and will cause Autoburn to go Haywire. Also, dont switch between realtime and off axis during the burn.

 

[Usonian]

I have been running IMFD 5.3 a LOT ... and have had zero problems.

Thanks for the quick reply -- nothing more reassuring than the voice of experience. IMFD has quirks and shortcomings, just as one would expect from something so complex, yet offered at no cost.

I hesitate to suggest anything that will add to your own uncompensated labors, but you might want to highlight the IMFD pitfalls, perhaps even add a separate section of Dos, Don'ts & DON'T EVERs! If you don't include these in your manual you will surely have to write them up later in replies to Forum comments.

You are attempting something that is extremely difficult to do: Master all the fine details of a complex topic and then, putting yourself in the place of a reader who knows nothing, try to explain it. If you succeed, your Manual/Tutorial will become an instant Orbiter classic! I wish you luck.

 

[jedidia]

jedidia, were you using XP or Vista? Honestly I don't think Vista is an issue, but then again I have never tried it on Vista, so I'll do that today and see.

Good ol' 2k here...

No, I don't think the OS is a problem either. I have been able to reproduce above behaviour enough to come to a rather stable conclusion on when it occurs: In an ejection burn that's started some time behind shedule.

I'm switching view every now and then, but the only thing I can tell about it is that IMFD seems to not be updating while in external view, but usually doesn't have trouble when getting back into cockpit.

. The only thing is though that for Orbit Insert, I use IMFD 4.2.1 (I have 4.2.1 and 5.3 installed)

Ah! now I'm kind of reassured. I never had problems with Orbit inserts with 4.2.1 (there were none to be had, after all... it did a pretty amazing job completely autonomous), but was never able to get the Orbit insert to work with 5.3. So there IS a bug in there.

 

[insanity]

The problem with crashing into planets during orbit-eject seems to be caused by running the orbit-eject program in realtime mode instead of off-axis mode.

 

[markl316]

I hesitate to suggest anything that will add to your own uncompensated labors, but you might want to highlight the IMFD pitfalls, perhaps even add a separate section of Dos, Don'ts & DON'T EVERs! If you don't include these in your manual you will surely have to write them up later in replies to Forum comments.

Nice idea. Kinda like the seven deadly sins of IMFD and a list of "Make your life a lot easier by always following these simple rules..." I'll make Appendix F: The Few Secrets of IMFD that will make your Life Easier and Appendix G: The Major Do’s and Dont’s of IMFD.

And this message is not only to you but to everybody--please, do not hesitate to suggest anything that you think I should add. This project is not for me--it is for YOU, and all of you who need help operating IMFD. I am not doing this for myself--I am doing this so that every person who wants to can explore the solar system using IMFD in the same amazingly rewarding way that I have been able to. If you think you have a suggestion that will help people use IMFD better, or you have a "helpful hint" or "little trick" that you think will make the use of IMFD easier, please tell me on this thread so that I can put it in.

The problem with crashing into planets during orbit-eject seems to be caused by running the orbit-eject program in realtime mode instead of off-axis mode.

Very true statement--that is why in my manual, I recommend doing the burn in Off-Axis mode, letting it completely finish, then switching to realtime mode and hitting autoburn again to get the dV perfectly (or as close as it will go) to zero.

 

[jedidia]

The problem with crashing into planets during orbit-eject seems to be caused by running the orbit-eject program in realtime mode instead of off-axis mode.

I am pretty sure I was doing it off-axis the first time it happened... I will try it some more times this evening to see what happens.

 

[markl316]

I am pretty sure I was doing it off-axis the first time it happened... I will try it some more times this evening to see what happens.

Actually, I just had a problem with off axis last night, my orbit matched the target orbit perfectly and it did not shut off the engines. Despite what everybody else says about realtime mode not working during ejection burns, I always use it, and it works perfectly for me. Plus, with realtime, I can see the dV decreasing. If off-axis mode fails, try realtime mode and see how that works.

 

[n122vu]

Some very useful info about IMFD provided by Pirx over at DanSteph's forum. covers v4.2, but concepts are the same. Main reason I am linking is that the last two posts mention the "AB firing into Earth" issue. Has to do with ejection time. Also, Prix mentions switching to realtime, then back to Off-axis to get an optimal TEj

http://orbiter.dansteph.com/forum/read.php?f=1&i=18317&t=18317&page=2

 

[jedidia]

I can definitaly confirm that it happens when you start your orbit eject burn after shedule (i.e. some time after TtB has reached 0). When it occurs seems to depend on how late your burn was. when you wait too long it seems to turn directly into earth. Hypothesis: the ship turns around when the sheduled burn would be finished. Can't be sure about that, but the behaviour can be reproduced very reliably as described above.
teaches you well to keep a date, that girl...

 

[Kveldulf]

One thing I do in Orbit Eject burns is change the PRJ to Self, and look at the planned trajectory. In the situations I've been able to test, it has shown me if I will be crashing into Earth after the burn, at which point I switch from Realtime or Off-Axis, and get a new Eject time.