How do you plan your interplanetary transfers?

[pauix]

At first I needed an angle chart, now I eyeball it and do a few corrections along the way to tune the encounter.

[Kruleworld]

I use the game's node thingys. just keep adjusting them until i hit the next body's SOI.

[loppnessmonsta]

ashamed to say i stay in kerbin's SOI. i plan to eventually move on, but i keep finding cool new mods to try out, and starting over, etc. i launched a few probes out beyond kerbin's SOI, but they didn't go anywhere after that.

[Tw1]

someone (and I wish I'd noted who) pointed out a very cool way to get spot-on transfers for every simple transfer in-game and I think I'll be doing that from now on.

-snip of brilliance-

That's very clever. I'll also do this from now on.

[Mighty1]

I used to use Alexmoon's calculator and loved it. However someone (and I wish I'd noted who) pointed out a very cool way to get spot-on transfers for every simple transfer in-game and I think I'll be doing that from now on.

Was it the system when you watch the planet in the lower orbit and when it, sun and planet in higher orbit make a right sided triangle you launch tward it? Depending on the place you want to go the planet in higher or lower orbit is your starting location.

[Superfluous J]

I used to use Alexmoon's calculator and loved it. However someone (and I wish I'd noted who) pointed out a very cool way to get spot-on transfers for every simple transfer in-game and I think I'll be doing that from now on.

Was it the system when you watch the planet in the lower orbit and when it, sun and planet in higher orbit make a right sided triangle you launch tward it? Depending on the place you want to go the planet in higher or lower orbit is your starting location.

No, it's the rest of the post that you quoted, but snipped off...

• Once you're in orbit around Kerbin (or whatever planet/moon), set up an eject maneuver node to JUST leave the SOI to Sun's SOI. Ideally within 1m/s of staying caught. Make it on the correct side (retrograde for going inward toward Sun, prograde for going outward away from Sun).
  
• The resultant Sun orbit will be just ahead or behind Kerbin's Sun orbit. Place a maneuver node on that projected orbit, and plan your burn to your target planet. Drag the node around and fix prograde/retrograde or whatever until you get an encounter.
  
• Delete the FIRST maneuver node, and the SECOND one will become a timer to about the right time to eject.
  
• Fast-forward to that maneuver node, but don't do it. Just delete it once you reach it.
  
• Plan a new Maneuver node to actually do the transfer, and then do it.
  
• Revel in the fact that you just did an in-game efficient transfer without using an external tool.
  

[White Owl]

I used to use Alexmoon's calculator and loved it. However someone (and I wish I'd noted who) pointed out a very cool way to get spot-on transfers for every simple transfer in-game and I think I'll be doing that from now on.

• Once you're in orbit around Kerbin (or whatever planet/moon), set up an eject maneuver node to JUST leave the SOI to Sun's SOI. Ideally within 1m/s of staying caught. Make it on the correct side (retrograde for going inward toward Sun, prograde for going outward away from Sun).
  
• The resultant Sun orbit will be just ahead or behind Kerbin's Sun orbit. Place a maneuver node on that projected orbit, and plan your burn to your target planet. Drag the node around and fix prograde/retrograde or whatever until you get an encounter.
  
• Delete the FIRST maneuver node, and the SECOND one will become a timer to about the right time to eject.
  
• Fast-forward to that maneuver node, but don't do it. Just delete it once you reach it.
  
• Plan a new Maneuver node to actually do the transfer, and then do it.
  
• Revel in the fact that you just did an in-game efficient transfer without using an external tool.
  

I used MechJeb simply because I wanted the calculation to happen ingame, without using an external tool, and I'm playing in an unusually rescaled system so most of the usual resources wouldn't help anyway; all the timing and delta-V numbers are different. But now this simple technique sounds perfect! Thanks so much.

[Concentric]

I've been using a method of tangents I found somewhere on this forum: take the two planets between-which you are transferring, then look along a tangent to the orbit of the inner planet from its location and in the same direction as it is traveling, and begin transfer when the outer planet lies ahead of you on that line. It's an easy method to eyeball and seems to work pretty well.

Before that, I just winged it with a maneuver node and corrected on the way out, so I don't have much background to compare it against. I might give the method 5thHorseman mentioned a try.

[Godot]

I used the transfer calculator before some time ... nowadays I prefer Alexmoons Launch WIndow Planer as it also helps me to set a launch day for a dV efficient transfer

[EpicRootHairCell]

Fan of http://alexmoon.github.io/ksp/ all the way. Probably wouldn't use it for Duna or Eve but all the others the inclination makes it to expensive to hit reliably otherwise.

[HafCoJoe]

I've memorize the basic transfer windows between planets and I just map it out. I guess you could say a lucky guess but I just know the basics to do it. So not exactly a guess.

[wooaa]

You plan transfers? I just go when I feel like it and find a way to make it work. I will admit that it is very fuel intensive but i find it fun.

[Felsmak]

I check the Interplanetary Calculator for the phase angle. Then I load the rocket and timewarp until the solar system looks kinda like it does in the Calculator, and then I switch to something else that's already in orbit around Kerbin and use maneuver nodes to see if that could theoretically go to my chosen destination. If it can, I switch back and launch away. If it's too early, I timewarp some more; and if it's too late, the wall gets a new hole.

[Caelib]

My tried-and-true method is to leave Kerbin's SOI then use a maneuver node.

[Dooz]

Maneuver nodes

[TechnicalK3rbal]

Kerbal Alarm Clock and KSP.Olex.Biz

[Superfluous J]

My tried-and-true method is to leave Kerbin's SOI then use a maneuver node.

This hurts me to read. Getting to the planet directly from LKO uses less fuel than the maneuver node you used outside of Kerbin's SOI, and that doesn't even take into account the 1000 or so dV it takes to get from LKO to Kerbin's SOI.

Or to say it with an equation (who doesn't like equations): (Your Method) = (Efficient Method)*(losses from not using Oberth Effect) + (dV you spent getting out of Kerbin's SOI)

I don't know exactly, but I think it's close to M_y=M_e*1.2+1000.

Or if it takes me 1200 dV to get to Duna, it takes you about 2400(!)

You probably don't care but like I said, it actually hurts me to think of all the payload you're not bringing so you can carry all that fuel.

[Caelib]

This hurts me to read. Getting to the planet directly from LKO uses less fuel than the maneuver node you used outside of Kerbin's SOI, and that doesn't even take into account the 1000 or so dV it takes to get from LKO to Kerbin's SOI.

Or to say it with an equation (who doesn't like equations): (Your Method) = (Efficient Method)*(losses from not using Oberth Effect) + (dV you spent getting out of Kerbin's SOI)

I don't know exactly, but I think it's close to M_y=M_e*1.2+1000.

Or if it takes me 1200 dV to get to Duna, it takes you about 2400(!)

You probably don't care but like I said, it actually hurts me to think of all the payload you're not bringing so you can carry all that fuel.

I think it all comes down to fun-factor and the "stock experience". When Squad adds stock TWR and Delta-V information, I may considering making more efficient systems so right now I just make everything over-enough.

I haven't done much interplanetary transfers with the new-and-improved system added in .23.5, but that should help quite a bit with efficiency.

[NecroBones]

Fan of http://alexmoon.github.io/ksp/ all the way. Probably wouldn't use it for Duna or Eve but all the others the inclination makes it to expensive to hit reliably otherwise.

Yes, this. Not such a big deal for Duna and Eve, but I use it for those anyway. After calculating the windows, I set up alarms with KAC, set for a few hours early.

[JayKay]

I use the olex site for planning transfers. I had some consternation at first, though, since Kerbal Alarm Clock and olex didn't seem to agree on timing. Then I noticed that you could select between Kerbal Days and Earth Days on the site, which does tend to skew the results, when you leave it on Kerbal days...

JK

[Temeter]

I actually did the first duna and moho transfers by hand. Didnt even know how maneuver nodes or actual interplanetary transfers worked. Surprisingly enough, the moho-mission was one of the most flawless missions ive ever done. Absolutely everythig went fine, including return and landing on kerbin.

After that, usually Olex.biz. If you learned how interplanetary transfers work and tried all options, there isnt a reason to make it unecessary complex imo. You will need additional tools anyway.

I use the olex site for planning transfers. I had some consternation at first, though, since Kerbal Alarm Clock and olex didn't seem to agree on timing. Then I noticed that you could select between Kerbal Days and Earth Days on the site, which does tend to skew the results, when you leave it on Kerbal days...

JK

Yeah, that had me confused quiet a bit. Even more, because in earlier versions you couldnt look up the date mid flight, and Mechjeb often confused a year, a day or both of it. Then Kerbal Days came, and the confusion just grew...

Glad i solve that, though.

[aleis]

Wait until target is at about the right angle. Then wait for either dusk or dawn depending and just point up, light the fuse and hold on

[Taki117]

I use MechJeb, KAC, and Alexmoon's website. I use the Website for rough planning (How much dV and mission time is it going to take) and then I use KAC to help me remember when I need to get into space, then I use MechJeb to execute the burn for me.

[TotalNewb]

I just throw some stuff together in the VAB, get it into Kerbin orbit, then Kerbol orbit and then "Let's plop this maneuver node here, at the apoapsis, and lower the periapsis... No encounter? Let's move it around a lit- I saw that! Get back here, encounter! Good. I hope I have enough fuel for that."

[Pwnstarr]

I voted "lucky guess," which means I play with maneuver nodes to find decently close intersection.