IMFD ISS intercept

Delta glider

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Now, a strange problem I have been having is that I can not get IMFD to do an ISS intercept situation. What happens is that the minimal DV I get is like 500 m/s and is all inward-outward. Any suggestions?:)



:hailprobe:

---------- Post added at 07:28 PM ---------- Previous post was at 07:15 PM ----------

Oh, I am in a 200km by 200km orbit, perfectly aligned with the ISS.
 

boogabooga

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I don't use IMFD for LEO interceptions.

All it knows is how to get you there by performing the burn when you tell it to (TEj) and have you arrive when you tell it to (TIn). An efficient interception is all about timing both TEj and TIn properly. You need to know what you are doing.

All I can say is to try to adjust TEj and TIn until you get a Hohmann transfer, if you know what that is.
 

Delta glider

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All I can say is to try to adjust TEj and TIn until you get a Hohmann transfer, if you know what that is.
Well, all I want is a method that can intercept the ISS not miss by 80 km.:lol:
Because I hate being far away from the ISS and not being able to get to it.
By the way to get a Hohmann transfer you need a lot of time adjusting.
What do you use?
 

Malky

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I recommand using SyncOrbitMFD (or something like this :D ) it's MFD in basic Orbiter package and it's enough for simple rendezvous, also it's much easier to understand than IMFD :)
 

boogabooga

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[ame="http://www.orbithangar.com/searchid.php?ID=1199"]Rendezvous MFD 050621[/ame]

[ame="http://www.orbithangar.com/searchid.php?ID=4889"]Precession MFD[/ame]
 

Delta glider

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I recommand using SyncOrbitMFD (or something like this :D ) it's MFD in basic Orbiter package and it's enough for simple rendezvous, also it's much easier to understand than IMFD :)

I can do a rendezvous with it but it is not accurate enough. (80-200km) off.
And rendezvous MFD requires you to be within 100 km of the target.

---------- Post added at 04:06 PM ---------- Previous post was at 02:59 PM ----------

Solved! Using IMFD I managed to get 1 burn to make me pass through the ISS.

---------- Post added at 04:07 PM ---------- Previous post was at 04:06 PM ----------

If an admin could rename the thread please!:cheers:
Or delete it.


:hailprobe:
 

Donamy

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UAP will do it for you.
 

Malky

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I can do a rendezvous with it but it is not accurate enough. (80-200km) off.

It might not be perfect, but I never had problem to get close enough to start docking using other tools (dock HUD or RV MFD) - that means from single digits kilometers to tens of meters :)

But if you solved your problem, then everything's alright I guess :)
 

TachyonDriver

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Ask yourself - What is the ISS orbital altitude in Orbiter?

Assuming I'm playing catch-up to the station I just get into an orbit a few km lower at apoapsis than the ISS periapsis. Then I set sync orbit to Ship apoapsis, wait until the ISS is at or near its closest distance to me, then fire up the docking mfd and....dock.
 

Cras

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IMFD is good if you gotta get to the station RIGHT NOW. If you are looking for a fuel efficient method for the Shuttle, you gotta learn how to phase your orbit.

Align your plane. Do a burn that puts your apogee about 4 meters under your targets apogee and align those nodes so that you and your target hits apogee at the same point.

Use Sync MFD, set it for target apoapsis, when you hit apogee burn forward to raise your perigee. You will see the DTime start to change. Let it run to zero and count up to about 2.

Let the sim run until you hit that point. Burn forward with RCS again, this time let DTime run down to zero and back up to about 0.4

You will drift right up onto the R-Bar of the ISS, and you should be able to figure out how to do the rest from there. Takes very little fuel, you will have plenty of juice in the OMS tanks.
 

Cras

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The DTime of 2 will get you fairly close, about 50,000 feet behind the station or so, give or take your altitude. The reason for that is so that your final orbit, the one which at the end of you will be at the ISS, will be pretty much in control, your eccentricity will not be too large, you will do a pretty straight forward dip down and catch up to the station.

You can skip that step and go straight for 0.4 if you want, you may notice your path to the station be a bit odd but you will still get there, but aiming for that DTime of 2 first will just sort of get you in a more controllable final approach. 0.4 is so that you hit the station underneath and slightly behind it, it is a more stable place to be when taking over manual control, you will find it easier to null out your relative velocity from there than if you want to hit the R-bar right on the money.
 
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