How to reach a ship in Solar Orbit?

[maddog59]

I'm trying to figure out how reach a couple of ships that in a solar orbit that's slightly higher than Kerbin's, and I'm having a difficult time trying to get a good intercept. I figured I'd use the alexmoon launch window planner, but when I go to the 'add a body' window to add the vessel information, I don't know where to find all of the information it's asking for; some of it is clear in the Orbit Information widget (or whatever it's called, lower left corner under the staging icons), but other info is a mystery to me. If anyone can point me to where I'll find the following (or which fields in the Orbit widget has it), I'd be very grateful: 

1. Semi-major axis;
2. Longitude of Ascending Node;
3. how to correctly calculate the Time of Periapsis passage. 

Alternately, if there's another planner out there that will make this task easier, I'd appreciate hearing about it. 

Thanks!

[jimmymcgoochie]

Try using MechJeb’s advanced transfer manoeuvre planner, it does the hard work for you- all you need to do is select the target and it’ll produce a porkchop plot for delta-V and can plot the nodes for either minimum delta-V overall (your typical Hohmann transfer) or just the most efficient trajectory RIGHT NOW if you’re in a hurry.

[Corona688]

You're not finding a good intercept for that because there isn't one.  Going sideways like that either takes tremendous amounts of time - about what it took for your target to get there - or tremendous amounts of energy to force a straighter line.

[Mikenike]

On 11/1/2020 at 12:27 PM, maddog59 said:

Alternately, if there's another planner out there that will make this task easier, I'd appreciate hearing about it. 

Mechjeb is a savior here. Or you can call on @Lewie and his Kerbal Rescue deal. He has guys who could handle it I'm sure. We've been visited by the great Matt Lowne himself, so even a youtube with thousands of subs noticed. I think that Lewie and The Doodling Astronaut could handle it.

[Misguided Kerbal]

Have you ever performed rendezvous and docking? It's the same basic principle, but scaled up. Set the ships you're trying to get to to your target, and then make the orange or purple things line up.

[Lewie]

The kerbal rescue force would be glad to help, but if you want to do it yourself, I’d recommend just fiddling around with nodes. If you could show us a screenshot, that could help out.

It’s rather easy-

Try to get an encounter of 1 million kilometers, and just adjust from there. Burning towards/retrograde relative to the target will help you out.

Edited November 5, 2020 by Lewie

[Geonovast]

Moved to Gameplay Questions as this isn't a tech support issue, but a "how to play the game" issue.

[theAstrogoth]

I'll shamelessly plug my own tool here, which could helpful! If you're on PC, you can upload your savefile (persistent.sfs or a quicksave), and the app can pull orbital parameters from all crafts/asteroids/comets in your save. It can also help you plan a transfer trajectory.

If you try it out, let me know if you have any questions.

[maddog59]

Thanks to everyone for the suggestions and ideas, as well as the offer of the Rescue Force. Part of the problem (I think) is that I'm starting from Mun orbit, and not going for a gravity assist by diving into Kerbal's well; the other is that I may just not have sufficient dV (unless I'm willing to wait a year or so for the everyone to get back together. I'm patient, but not THAT patient!).  

And thanks for moving this to the correct forum, Geonovast!

20 hours ago, Misguided Kerbal said:

Have you ever performed rendezvous and docking? It's the same basic principle, but scaled up. Set the ships you're trying to get to to your target, and then make the orange or purple things line up.

Oh yes, quite a bit .... I have a number of fueling stations in orbit around Kerbin and Mun that I use, and that was the original idea I was following when trying to catch up to my Solar ships. But I just can't seem to get to less than several hundred thousand km's ... and part of it is the lack of dV, as well as willingness to warp forward 2 or 3 dozen days. 

[Zhetaan]

On 11/1/2020 at 1:27 PM, maddog59 said:

I'm trying to figure out how reach a couple of ships that in a solar orbit that's slightly higher than Kerbin's, and I'm having a difficult time trying to get a good intercept.

I should caution you that if you're starting from Kerbin, and this target is just outside of Kerbin orbit, then you may need to wait a prohibitively long time for a transfer window.  The closer two objects are, the longer their synodic period, which is to say the time it takes for them to repeat their closest approach.  It may be faster (albeit not cheaper, but sometimes, that's not the most important) to go into a phasing orbit with more frequent transfer windows.