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Old 01-09-2013, 08:16 AM   #1
Max Pain
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Question From Europa to Earth

Hello,

I have my spaceship landed on Europa, now I want to fly to Earth using IMFD 5.5.

The problem is, that for the Target Intercept program the source Body is Jupiter. When I do the Orbit Eject program, I eject from Europa. Therefore, I am still in Jupiters gravity and Orbit Eject doesn't work. Setting the reference in Orbit Eject to Jupiter is also not the best idea because of the gravitational influence of Europa.

I know that a hackish would be to simply get first in Jupiter orbit and then eject, but I would prefer to eject with only one burn from Europa. I'm playing with the thought that maybe the Slingshot program provides an solution? And I want to do this with IMFD, I know that Transx is better suited for this task.

Thanks and Regards,

Georg
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Old 01-09-2013, 08:17 AM   #2
Cras
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To go from the moon of a planet to another planet, you need to use the Slingshot program.
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Old 01-09-2013, 08:59 AM   #3
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I would recommend you to use TransX here instead of IMFD
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Old 01-09-2013, 09:09 AM   #4
Cras
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IMFD works perfectly well in this situation. I have done it. From Europa even.
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Old 01-09-2013, 06:21 PM   #5
dgatsoulis
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Quote:
Originally Posted by Max Pain View Post
 I would prefer to eject with only one burn from Europa. I'm playing with the thought that maybe the Slingshot program provides an solution? And I want to do this with IMFD, I know that Transx is better suited for this task.

Thanks and Regards,

Georg
You are right to think that the slingshot program is the solution. I recorded a quick video showing you how to do it, but my mic was on "mute" (Not the first time this happens).

Still you will be able to see the setup. Try it and come back with any questions you might have.



Perform the first correction when you are outside of Jupiter's SOI.

Last edited by dgatsoulis; 01-09-2013 at 06:37 PM.
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Old 01-09-2013, 07:05 PM   #6
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I would also use TransX, but I never use the other mfd's mentioned, so I can't say if one works better than the other
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Old 01-09-2013, 07:27 PM   #7
dgatsoulis
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For a direct "landed on moon of a planet to another planet" journey, IMFD provides a solution without the need for surrogate ships.

You can do it with TransX, but you need either a surrogate ship already in orbit around the moon or two separate instances of TransX.

I always have this setup on my Orbiter installation, so I can choose which one suits me best.

A combination of TransX for the intial setup and then IMFD's Delta Velocity and Map programs provide the best results for almost any situation in Orbiter.
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Old 01-09-2013, 07:30 PM   #8
Max Pain
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Thanks a lot for your support ! Tried it now and it spared me a lot of fuel. I see that it is not as exact as a direct ejection (when Jupiters gravitational influence was zero, I had to do a correction burn with a dV of 500 m/s), but for now I am happy.

Regards
Georg
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Old 01-09-2013, 08:53 PM   #9
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Here's a TransX plan from LEO (Low Europa Orbit) that has a pretty good Earth Encounter for about 5.9kDV. In practice I'd make this burn then just make a course correction once I got out of Jupiter's area.

---------- Post added at 12:53 PM ---------- Previous post was at 12:50 PM ----------

I don't know what people use surrogate ships for. I've heard of people using them, but never figured out exactly why. It is required to start from a moon surface?
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Old 01-09-2013, 09:12 PM   #10
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You cannot setup a TransX plan from a moon to another planet without already being in orbit first. So you either need a surrogate ship or two separate instances of TransX to do it.

1.Surrogate ship method:
You place one ship in orbit around the moon you are landed and use it to setup the plan. Then you go to the landed ship and launch to be in plane with the surrogate. Once in orbit, you inherit the plan from the surrogate and continue with the rest of the flight normally.

2. Using two instances of TransX:
You start the plan from stage3 where you have to use the Cruise Plan: Eject. Then you go to stage2 and setup the Initial plan: Escape.
Now you need the second TransX- stage1 escape , stage2 Plan: None
You match the trajectory of stage2 of the first TransX and now you have a launch heading in stage1 of the second TransX. (Confused yet?)
After you get in orbit, you can close the second TransX and continue as usual with the first one.
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Old 01-09-2013, 09:17 PM   #11
Cras
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or, use IMFD.


Sorry for sounding like a broken record, but I really like IMFD. It is a wonderful tool.

Last edited by Cras; 01-09-2013 at 09:19 PM.
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Old 01-09-2013, 09:25 PM   #12
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Quote:
Originally Posted by Cras View Post
 or, use IMFD.


Sorry for sounding like a broken record, but I really like IMFD. It is a wonderful tool.
I like it too, it's great.
But i think it's always good to know at least two ways to solve a problem.

For example: how about a trip from Brighton beach to Olympus base, using minimum ΔV?
IMFD can provide a solution but it uses too much fuel. In this case TransX gives better results.
Or even better, use TransX for the initial setup, perform the burns and know when and where you are going to arrive with IMFD.

EDIT:
In the example above, I'm talking about a solution that utilizes the Oberth effect.

Last edited by dgatsoulis; 01-09-2013 at 09:36 PM.
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Old 01-09-2013, 09:29 PM   #13
Cras
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That is a good point, and one I have often thought about. I do need to learn TransX a bit better and just use IMFDs dV program for the burns.
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Old 01-09-2013, 09:59 PM   #14
statickid
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Quote:
Originally Posted by dgatsoulis View Post
 You cannot setup a TransX plan from a moon to another planet without already being in orbit first. So you either need a surrogate ship or two separate instances of TransX to do it.

1.Surrogate ship method:
You place one ship in orbit around the moon you are landed and use it to setup the plan. Then you go to the landed ship and launch to be in plane with the surrogate. Once in orbit, you inherit the plan from the surrogate and continue with the rest of the flight normally.

2. Using two instances of TransX:
You start the plan from stage3 where you have to use the Cruise Plan: Eject. Then you go to stage2 and setup the Initial plan: Escape.
Now you need the second TransX- stage1 escape , stage2 Plan: None
You match the trajectory of stage2 of the first TransX and now you have a launch heading in stage1 of the second TransX. (Confused yet?)
After you get in orbit, you can close the second TransX and continue as usual with the first one.
I think i'd just launch into a nice orbit, then plan. My Europa-Earth transfer was easy enough to build for my tastes, lol!
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Old 01-10-2013, 04:45 AM   #15
Tommy
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Quote:
Originally Posted by dgatsoulis View Post
 I like it too, it's great.
But i think it's always good to know at least two ways to solve a problem.

For example: how about a trip from Brighton beach to Olympus base, using minimum ΔV?
IMFD can provide a solution but it uses too much fuel. In this case TransX gives better results.
Or even better, use TransX for the initial setup, perform the burns and know when and where you are going to arrive with IMFD.

EDIT:
In the example above, I'm talking about a solution that utilizes the Oberth effect.
In the above case, the Oberth Effect doesn't come in to play anyway - the energy required to escape the moon will provide all the dVf you need, so you won't need a prograde burn at Earth. Any burn you do make there will be an alignment burn - and that's the worst time for alignment burns.

If your IMFD solution is using too much fuel, you haven't set it up correctly - this flight should only require one main burn - the Moon Ejection. After that it's just MCC's.
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