eve flyby with mechjeb

[antipro]

objective: simply eve flyby using mechjeb and lowest amount of fuel.
situation: I'm on launchpad completely lost on what to do.

I open ASCENT GUIDANCE and I read "Select a target for timed launch" so I select EVE as a target.
At this point 2 new buttons appear: "Launch to rendezvous" and "launch into plane of target".
At first I press "Launch to RV", a timer of about 5h appear and Orbit Inc stay 0°
Then I try with "Launch into Plane", a timer of about 2h appear and Orbit Inc change to "2.099"

At this point, before launch, what I have to do?

[DerekL1963]

16 hours ago, antipro said:

objective: simply eve flyby using mechjeb and lowest amount of fuel.
situation: I'm on launchpad completely lost on what to do.

The easiest way is to launch into a parking orbit, and then select "transfer to another planet" from the maneuver planner.  If you don't depart in the proper window, you'll consume massive amounts of fuel.

Eyeballing your vehicle, you're going to be cutting it pretty fine as it is.  I hope you're not planning on Jeb coming home...

[antipro]

49 minutes ago, DerekL1963 said:

to launch into a parking orbit

what is a parking orbit? is it a simple equatorial orbit around kerbin?
 

54 minutes ago, DerekL1963 said:

you're going to be cutting it pretty fine as it is

excuse me, this means "To have a very narrow margin for error or deviation"?
 

59 minutes ago, DerekL1963 said:

I hope you're not planning on Jeb coming home...

after flyby eve at an altitude of 92km, I can return to kerbin even if it takes about 5 years to reach the node and having only 100m/s dV for decelerate before enter atmosphere, so maybe I will add a bit of fuel.

[antipro]

anyway... I've launched immediately to a 90km kerbin orbit.
Then I've used "Maneuver Planner - Transfer to another Planet", but I can't intercept EVE.
and the node dV indicator is counting, I mean it increase.. why?

https://www.dropbox.com/s/w497ubjv3tnui5l/2020-09-12 20-30-00.mkv?dl=0

[DerekL1963]

1 hour ago, antipro said:

what is a parking orbit? is it a simple equatorial orbit around kerbin?

 

1 hour ago, antipro said:

excuse me, this means "To have a very narrow margin for error or deviation"?

Yes to both.
 

1 hour ago, antipro said:

after flyby eve at an altitude of 92km, I can return to kerbin even if it takes about 5 years to reach the node and having only 100m/s dV for decelerate before enter atmosphere, so maybe I will add a bit of fuel.

I'd launch with closer to 4k d/v, preferably 5k...  but that's just me.

 

44 minutes ago, antipro said:

Then I've used "Maneuver Planner - Transfer to another Planet", but I can't intercept EVE.
and the node dV indicator is counting, I mean it increase.. why?

The initial departure burn _should_ be much closer, and then you do a "fine tune closest approach" burn.  I have no idea what it isn't or why your d/v counter is changing.

 

[antipro]

16 minutes ago, DerekL1963 said:

I'd launch with closer to 4k d/v, preferably 5k... 

that ship already has 5,2k dV

 

20 minutes ago, DerekL1963 said:

The initial departure burn _should_ be much closer

closer to what? you mean closer in time, so less than 411 days?

 

[DerekL1963]

23 minutes ago, antipro said:

closer to what? you mean closer in time, so less than 411 days?

Mistyped because I was also paying attention to something on the stove...

"The initial departure burn _should_ provide a much closer encounter."

[lemon cup]

Based on your video, looks like you’ve decided to go to Eve and told MechJeb that you would like to do so. So what Mechjeb has done is find you the cheapest  dV option to transfer. You can see that the readout next to the Navball says -411 days, that means you would have to time warp 411 days and THEN make the burn. If you were to burn now, you would see the burn indicator start to increase because you are not in the correct spot.

Default MechJeb is programmed to find the cheapest option, even if it means waiting a year. If you want to go to Eve sooner, choose the “advanced transfer to another planet” option in Maneuver Planner, then choose the “porkchop” option. You will see a rainbow graph come up. If you then press Create Node it will again plot you a maneuver in 411 days, by default, but you can use your mouse to hover over spots on the graph and manually select when you would like to leave and how much fuel you will use - that information is displayed right below the graph as you move your mouse across it.

Look for blue colored spots on the left of the graph, those represent the cheapest and soonest times to leave. You can use the mouse wheel to zoom in on the graph for extra precision. When you have found a good spot, click that spot once and then hit “create node.” Wait for the correct amount of time and then make the burn. 
 

(Anti)Pro Tip: I see you have Kerbal Engineer as well as MechJeb. I do too. I have found that if you use Kerbal Engineer in the tracking station to predict transfer windows to other planets, it is best to leave a few days early. MechJeb might not agree, and might tell you to wait a whole extra year. Manually choosing with the porkchop fixes this, but getting to orbit a few days early gives you extra time to find the right spot, and more blue space to choose from.

Edited September 13, 2020 by lemon cup

[antipro]

1 hour ago, lemon cup said:

choose the “advanced transfer to another planet” option in Maneuver Planner, then choose the “porkchop” option. You will see a rainbow graph come up. If you then press Create Node it will again plot you a maneuver in 411 days, by default, but you can use your mouse to hover over spots on the graph and manually select when you would like to leave and how much fuel you will use - that information is displayed right below the graph as you move your mouse across it.

Look for blue colored spots on the left of the graph, those represent the cheapest and soonest times to leave. You can use the mouse wheel to zoom in on the graph for extra precision. When you have found a good spot, click that spot once and then hit “create node.” Wait for the correct amount of time and then make the burn. 

thx but it seems it does not work for me.
https://www.dropbox.com/s/5v3l7u578cyp4jk/2020-09-13 19-58-43.mkv?dl=0

[DerekL1963]

36 minutes ago, antipro said:

thx but it seems it does not work for me.

You've got something very weird going on there...  You don't have any physics or game altering mods installed do you?

[lemon cup]

34 minutes ago, antipro said:

thx but it seems it does not work for me.
https://www.dropbox.com/s/5v3l7u578cyp4jk/2020-09-13 19-58-43.mkv?dl=0

That is some very strange behavior, I see now what you mean by the maneuver indicator going up in dV cost, without you moving your craft at all.

My advice would be to select a spot that is much sooner than 1 year out, since you are dV constrained this may involve time warping 1 year, then attempting to plot the point. MechJeb could be struggling with the extra calculations involved with something that far out. (As for the disagreement between KER’s predicted transfer window and MJ’s, that looks normal to me).

If that doesn’t work, MJ maybe be confused about something on your craft engine/fuel related, perhaps some modded parts that are behaving in a way not expected.

Otherwise you might be experiencing a glitch related to mis-matched versions of KSP, MechJeb, and ModuleManager. But I’m afraid that is not my area of expertise. You could try posting what versions of these you are running, as well as a picture of your Game Data folder, and someone else might be able to go from there.

[antipro]

30 minutes ago, DerekL1963 said:

You don't have any physics or game altering mods installed do you

I've got these 4 only: X-Science - KER - Trajectories - Mechjeb

 

anyway, I notice that if the parking orbit is in high space or so, MJ still isn't perfect but it works: no more crazy maneuvers or dV indicator counts.
https://www.dropbox.com/s/wn4sxoobm84u3nc/2020-09-13 21-04-45.mkv?dl=0

Edited September 13, 2020 by antipro

[DerekL1963]

41 minutes ago, antipro said:

I've got these 4 only: X-Science - KER - Trajectories - Mechjeb

Honestly then, I have no idea what's causing your problems...  assuming you're running 1.10 or 1.10.1, you've got the correct version of MJ.