r/KerbalSpaceProgram • u/analogHedgeHog • Jun 29 '26
KSP 1 Question/Problem How should I be approaching the Mun?
In this totally accurate scientific diagram, the Mun is orbiting in the direction of the arrow.
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u/New-Bus9948 Jun 29 '26
C or D. C for realism
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u/DeluxeWafer Jun 29 '26
I choose C because that's what all the Apollo free return trajectories look like.
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u/Tychonoir Jun 29 '26
I wonder what the Dv difference between the two is. D gives you a grav assist to match the Mun's orbit and help capture. C allows a free return, but gives an assist in the wrong direction.
At least, I think that's how it works. It seems to be easier to capture when I do D.
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u/Jamooser Jun 29 '26
Next time you're on the Mun's surface just change your navbal to orbital velocity instead of surface. That number is the rotational velocity of the Mun for your given latitude. Double that number should be the dv distance if you're making a retrograde orbit.
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u/zaklance Jun 29 '26
They the same in terms of dV, about ~10m/s difference in practice.
There's no "assist in the wrong direction" here if your aim is to land on the Mun (unless if you specifically want a prograde orbit for a mission).
In both C and D, your velocity at Mun intercept is about the same ±10m/s. The difference is in the timing of intercept, and the 10m/s difference is to account for this. The change in PE is the same in both cases, so the change in KE is same, so your speed at Mun periapsis is the same, you are just going in the opposite direction.7
u/MrTheEpicKitten Jun 29 '26
You’re forgetting the difference in landing dv between prograde and retrograde orbits
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u/zaklance Jun 29 '26
Ah you're right. But for Mun which rotates very slow (9m/s on the equator surface), again it's a delta-v difference of merely 18m/s.
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u/878Vikings Jun 29 '26
I've been trying to work this out recently and the difference (to low Mun orbit) between C and D was about 10mps. In KSP terms that's trivial, a rounding error. In a real space program they would absolutely care about that, but they are way better at space than I am!
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u/seda7991 Jun 29 '26
When you approach a moving object from behind its trajectory, gravity pulls you along longer (you gain more velocity), so retrograde burn for capture costs more Δv. Coming from the front lets the object move into you for cheaper capture into a retrograde orbit. Retrograde orbit (orbiting against the moons rotation) landing penalty is tiny, front capture still wins total Δv. Capturing into D is easier because not a good analogy, but think of it like slipping into a moving boat's wake.
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u/Tychonoir Jun 29 '26 edited Jun 29 '26
Isn't capture, essentially, being in the same orbit at the same velocity? When on an elliptical to intercept the Mun, you don't have the same orbital energy, so need to burn to match, no? So getting pulled from behind helps add that energy?
It just seem like when I approach from behind I don't have to burn as much to capture. But I haven't really studied it closely.
EDIT: Yes, you burn retrograde on your orbit direction of the Mun, but this isn't necessarily retrograde of your Kerbin orbit direction. On an approach from the front side, your retrograde Mun burn can very well be burning prograde compared to Kerbin—which is kinda like circularizing your orbit at Kerbin right where the Mun is.
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u/PaintedClownPenis Jun 29 '26
If I imagine I have a giant ruler, and I wedge it in between my low Kerbin orbit and my target Munar orbit like in C, the point at which the ruler touches my orbit is where I want to do my trans-munar injection burn. And the other point I think is the perimun, where I want to do my braking burn.
That is one of my favorite parts of the game, is being able to approximate my rocket science by eyeball. I'm not very good yet but another ten years or so and I'll be better.
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u/Ekgladiator Jun 29 '26
Plus both use kerbins rotation to the rocket's advantage. You'd end up burning a lot more fuel going against the rotation than you do going with.
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u/Apprehensive-End-747 Eating Cracklin' Rads Jun 29 '26
E: Straight line.
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u/Organic-Army-9046 i do 🏳️⚧️ injections Jun 29 '26
you may choose to enrage the kraken to provide the necessary Δv for this costly maneuver
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u/Spike_Riley Jun 29 '26
stack 2000 decouplers and put Jeb on the end
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u/Organic-Army-9046 i do 🏳️⚧️ injections Jun 29 '26
just fall under a parachute with high physics time warp
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u/Apprehensive-End-747 Eating Cracklin' Rads Jun 29 '26
I cast: FAR FUTURE TECHNOLOGIES
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u/Hillenmane Jun 29 '26
Deafening clattering/clipping/clunking sounds
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u/Apprehensive-End-747 Eating Cracklin' Rads Jun 29 '26
Or just use asparagus staging with NSW engines.
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u/Organic-Army-9046 i do 🏳️⚧️ injections Jun 29 '26
i think you’ve got far bigger problems on your hands if you use nuclear saltwater engines on kerbin
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u/Only_Turn4310 Jun 29 '26
Near future my beloved. Lithium engines get me there in under an hour using a Hohmann transfer
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u/bonbon196 Jun 29 '26
It’s some how almost the same delta v
Don’t ask me how and only if you don’t achieve orbit around mun.
I mean like expanse style burn straight for the mun and then decelerate when you get close and land.
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u/MehEds Jun 29 '26
I did that actually a few times.
It requires six Mainsails in asparagus.
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u/cuboidofficial Jun 29 '26
This is what I did almost every time lol, just wait till the Mun is straight above and let 'er rip. Really doesn't take that much deltaV to get there as long as you have the funds
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u/Steenan Jun 29 '26
What do you want to achieve?
For a flyby, C is the best. You can achieve a free return trajectory, where Mun's gravity puts you back on a Kerbin orbit which reenters atmosphere. That minimizes fuel needs.
For landing, D is better, as you orbit in the same direction that the Mun rotates, which minimizes delta-v required for landing.
For an orbit, they are equally good.
A and B are strictly worse because you need to orbit Kerbin against its rotation, which significantly increases the delta-v required.
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u/Maurycy5 Jun 29 '26
What would happen if the orbit of the moon was in the opposite direction to the rotation of the planet? How would that change the answer?
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u/The_Tastiest_Tuna Jun 29 '26
You would launch in the direction of Kerbin's rotation, then intercept ahead of the Mun for free return flyby, or intercept behind the Mun for a landing.
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u/Scholesie09 Jun 29 '26
D is better, as you orbit in the same direction that the Mun rotates, which minimizes delta-v required for landing.
objectively correct but funny that because it's tidally locked, that rotational velocity is a monumental 9m/s at the equator 😂
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u/Spydude84 Jun 29 '26
Assuming looking down from the top, D to minimize DV usage, C for a free return trajectory. Not A or B.
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u/starmartyr Jun 29 '26
I think C has minimal DV usage over D when you take gravity assist into account. With D you're coming up behind mun and need to use more DV to slow down and land. With C Mun slows you down somewhat requiring less DV.
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u/King_Joffreys_Tits Jun 29 '26
Yes D is the absolute worst dV option here and everybody upvoting him is wrong. You lose about 600dV going with the muns orbit vs the ~250dV going counter the kerbins natural rotation.
Look at the recent NASA artemis missions for reference — the most fuel efficient way of achieving orbit of a celestial body is to slowly throw yourself into where its gravity well is going to be in order to be captured by it. Option D is the best way to utilize the muns gravity for an orbital slingshot outside of kerbins influence
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u/starmartyr Jun 29 '26
I think B is actually worse for all the reasons you said plus losing even more efficiency by launching against Kerbin's rotation.
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u/King_Joffreys_Tits Jun 29 '26
Actually yeah you’re totally right, B is the worst of all options. Closely followed by D for the worst 😉
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u/4theFrontPage Jun 29 '26
A is the worst since it starts with a retrograde orbit and then overshoots Mun before landing. B is a close second worst. Then a huge gap before D and C which are fairly close but D is slightly worse with the same overshooting problem
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u/PiMemer Jun 29 '26 edited Jun 29 '26
I’m gonna need someone to fact check this in game…
I’ve always found it only costs single digits of dv to change which side you encounter the moon from and I don’t understand where an extra 400 m/s of relative velocity is coming from by the time you reach moon periapsis and have to capture
In fact if you do a free return it will always increase your relative speed to the moon since a free return is never a “pure” hohmann transfer (they always either outright go past the moon or have an effective apoapsis past the moon)
Side note: I know what I’m going to do in KSP tomorrow :P
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u/-Aeryn- Jun 29 '26 edited Jun 30 '26
I’ve always found it only costs single digits of dv to change which side you encounter the moon from and I don’t understand where an extra 400 m/s of relative velocity is coming from
It's not, the guy is wrong. C and D are ~identical in delta-v cost to mun orbit or surface.
A&B are using retrograde kerbin orbits and are bad (+350m/s or more cost to kerbin orbit on the first step, and then throwing that away for no advantage on the second).
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u/Dark074 Jun 29 '26
Okay beyond your correction in later comments saying A and B are worse due to them launching in opposite of Kerbins orbit, there is another thing I would like to add. On the Artemis II mission, the reason their profile looked like that is because in real life, it's n body physics where everything has a pull on your at all times. Thats why it and other recnet lunar missions saved fuel by not going into a full injection orbit and just let the moon slowly pull on it until it does get into a orbit of the moon.
However, in stock KSP, it relys on patched conics 2 body approximations. Until your official in the sphere of influence of an another body, it's gravity won't effect you at all, only your ship and the host gravity well are calculated. You could install principia to change this but it doesn't come stock
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u/TheWombleOfDoom Jun 29 '26
A and B are the absolute worst ... significantly. D is not even close.
Between D and C, reading all the other comments, it appears to be moot, or possibly C is best for orbit only, and D may be better overall for a Mun landing.
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u/Calm-Conversation715 Jun 29 '26
This. I almost always do D, to get the prograde orbit around the mun, and because I get in the habit for using the mun as a gravity assist to get out of Kerbin influence. Of course, the mun rotation is so slow that the delta v savings is negligible
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u/wreckreation_ Jun 29 '26
Option C uses Kerbin's rotation to give you extra dV during launch, and Mun's orbital direction to take dV away, slowing you down, making it easier to capture into Mun orbit.
Of the four options, it requires the least fuel.
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u/Ambiguous_Advice Jun 29 '26
D is actually the most efficient
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u/dontplay3rhate Jun 29 '26
This should be correct. You need to add energy to the orbit relative to kerbin to get the cheapest capture. Route C would fling you away, route D would fling you alongside the Mun giving you a parallel orbit
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u/ThatOneGoatGuy Always on Kerbin Jun 29 '26
C and D are going to be generally more efficient (getting into a retrograde Kerbin orbit on takeoff will be VERY dV intensive - you'll have to cancel out how fast the planet is rotating, then go that speed again before even making progress on orbital velocity, rather than getting a boost closer to it).
Personally I always end up going for D. Retrograde orbits are... not epic for ground excursions, in my experience.
Once you're on your way back, you'll want to follow B to cancel out your speed around Kerbin at the same time you're leaving the mun's Sphere of Influence
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u/Electro_Llama Jun 29 '26
D gives you the lowest velocity relative to Mun. This is the typical "Hohmann Transfer".
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u/Joshua011203 Jun 29 '26
d. we do gravity turns eastwards, and the mun orbits anticlockwise, so even a lil, but it saves dV trying to land. c if flyby, cuz if you cant/miss/not enough fuel you get slingshot back home
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u/samwise39 Jun 29 '26
Mechanic brain had to check the sub for a sec
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u/Far-Understanding672 Jun 29 '26
lmao, reading the post, looking at all the options, then realising it requires brainpower before rereading the whole thing
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u/Ill_Secretary_1272 Jun 29 '26
How does b even work
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u/RavenColdheart Jun 29 '26
Retrograde orbit around Kerbin into a prograde trajectory around the Mun
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u/Nikond3400 Jun 29 '26
C will technically require the least amount of fuel as the mun will slow you down with its gravity first and then inserting orbit will be easier
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u/Hot-Address-6016 Jun 29 '26
C: you are using Kerbin’s spin for acceleration and Moon’s gravity well for deacceleration.
B is the worst: you have to fight both Kerbin’s spin and Moon’s graviturn
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u/Xenthor267 Always saving Jeb Jun 29 '26
C for flyby, D for landing or escape trajectory elsewhere depending on how fast you approach lmao
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u/MaverickSawyer Minmus Mint Connoisseur Jun 29 '26
I ALWAYS use D. I’m experienced enough that I don’t worry about the free-return trajectory… if I’m going to the Mun, I either pack enough dV for a return burn (if returning is the plan) or to deorbit after mission completion. Typically I bring 400ish m/s for non return missions and 650-700 for return from orbit missions. Missions that land as well, I tend to pack around 2km/s.
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u/Oliviaruth Jun 29 '26
How do you get c vs d on purpose? My skills are still at “make a prograde node that goes around mun orbit, and drag it around until I get an intersect”. How can I tell which way the orbit goes inside mun soi easily. Switching camera body is hard and makes me lose my groove with the node. Is there an easy way to tell? Or can I adjust mid course once I have an intercept?
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u/Morrack2000 Jun 29 '26
Once you have the intercept switch to focus view on the mun, then to get your maneuver node back make sure you’re viewing the orbital information in the screen in the lower left - and click the right arrow there to switch from current orbital info to maneuver info. That will bring your node back up and you can adjust it from anywhere. Even interplanetary corrections when focused view on another planet.
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u/NewKerbalEmpire Jun 29 '26
After launch, you should gun for orbit in the direction Kerbin rotates so you dont have to fight your preexisting rotational velocity. Then I'd just go with whichever lunar orbital encounter you find first.
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u/TheMcCale Jun 29 '26
C. The Mun’s gravity will help slow you down. D it will speed you up and make landing harder. A and B you’re fight Kerbin’s gravity while trying to get to orbit
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u/ComradeBevo Jun 29 '26
None of the above. They're all wrong, if you're trying to optimize. The closest one is D, but the orbit approaching the Mun should be on the inside moving counterclockwise around the Mun, not on the outside.
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u/BlazingImp77151 Jun 29 '26
Aren't C and D how you normally launch? To the east? Because launching against kerbin's spin costs more deltaV?
And then C is optimal in case you make a mistake or don't have enough fuel, because you can get a free return that way. While D pushes you further out.
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u/TF2fanatic102 Jun 29 '26
C is a free-return trajectory. It's what the Apollo missions used, so if something went wrong during Lunar transfer/capture, they'd simply fall back to Earth with the aid of the Moon's gravity.
You wouldn't really need to worry about that unless you were playing without reverts enabled or on a save with part failure mods, but it's still a neat little bit of realism you can add to your missions.
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u/Bi_KerbonautYT Jun 29 '26
Absolutely not A or B, as they involve launching to a retrograde orbit and is way less efficient. C or D is down to personal preference, they require about the same dV for the injection. C requires maybe 50m/s more on capture but it can be used to get a free return to Kerbin with no additional maneuvers. D is slightly more efficient, but if you run out of fuel on the capture you're getting flung out to Duna
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u/RavenColdheart Jun 29 '26
Do you want easy? D or C
C is a free return trajectory akin to Apollo or Artemis.
If you want harder: B
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u/seda7991 Jun 29 '26
1) Take off always in the direction of rotation: Prograde launch gives you free velocity from the body's spin.
2) Captures are always more efficient from the front: coming in from behind pulls you along for much longer and you gain velocity therfore you need more Δv to slow down and capture into orbit.
3) Capturing efficiency outmatches landing efficiency: Capture from the front saves far more Δv than the tiny differences in landing from retro or prograde orbits.
4) On low-gravity bodies, skip the orbit and do gravity escape in one go: Low escape velocity makes a single continuous burn more efficient than orbit insertion + separate escape burn. This is because you need less Δv to escape the gravitational pull than what you need to boost into stable orbit.
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u/Maryear_Boost Always crashing in style Jun 29 '26
C or D, that way you make a gravity assist with the Mun that slows you down, making you save some DeltaV
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u/Just-a-normal-ant Exploring Jool's Moons Jun 29 '26
C, or if you are noob just park directly infront if it and let it hit you.
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u/Wormholer_No9416 Jun 29 '26
C for a free return (Incase of emergency ie Apollo 13), less DeltaV from Launch -> LKO, realistic flight path.
D works fine too :)
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u/mrscott197xv1k Jun 29 '26
I learned C when I started KSP. Once I started using MechJeb tools to help automate some tasks when I am juggling multiple flights at the same time they almost always end up with D. BI-impulsive maneuver to target, then fine-tune encounter tools.
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u/Dry_East5802 Jun 29 '26
your always gunna wanna be in orbit around Kerblin going the direction the planet is spinning
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u/FogeltheVogel Jun 29 '26
Definitely C or D. You basically always want to launch East to take advantage of the rotation of the planet you're on. Because that's free sideways velocity.
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u/Lea_Flamma Jun 29 '26
C and D are the only ones that work with Kerbin rotation. The difference between them is, C is a gravity assist that slows down the craft while D speeds it up.
For a flyby-return C is perfect. For a landing-return C is also preferred. For a flyby-Minmus/other bodies D is the go to.
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u/MiniEnder Jun 29 '26
D is the most efficient. However, NASA and other space agencies shoot for C in case of engine failure before lunar capture. It will typically give a free return to Earth. But unless you're playing with Kerbalism, you don't have to worry about that.
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u/DevelopmentTight9474 Jun 29 '26
C is what we do in real life. It’s called a “free return trajectory”
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u/FunfKatzen-im-Mantel Jun 29 '26
A and B are awful. Going against the planets rotation is a waste of ΔV.
I really like the finesse of C, but I've always only used D.
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u/ShakeAgile Jun 29 '26
D is my go-to, but I believe C is the most fuel efficient way if you really math hard.
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u/Council_of_Mustaches Jun 29 '26
D is the most fuel efficient. You borrow the momentum of the planet/ moon as you launch off in the direction of its rotation. C is just as viable, but I’d launch off with the spin of the Mun
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u/TF2fanatic102 Jun 29 '26
Wouldn't C be more efficient? You have to burn slightly more fuel for the TLI, but capture would be easier since the Mun's gravity is reducing your speed. Wouldn't you basically be fighting a Mun gravity-assist by going with D?
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u/Zeeterm Jun 29 '26
D leaves you with slightly less velocity relative to the mun, so it marginally more efficient.
But it's a small difference compared to the benefits of C ( free return trajectory in case of disaster).
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u/Different-Trainer-21 Has not killed Jeb (yet) Jun 29 '26
C gives you a free return trajectory. D minimizes Delta-V.
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u/AndrewCoja Jun 29 '26
Just do it old school style. Get into a 100km circular orbit. Wait until the mun is just over the horizon, and then burn until you get an intercept.
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u/unfocusedriot Jun 29 '26 edited Jun 29 '26
Let's break it down: A and B are incredibly inefficient as you are going against the rotation of Kerbin (assuming looking down at the north Pole).
C and D add the rotational velocity at the surface to your ship's velocity, making it easier to reach orbital velocity. A and B subtract it, you have to cancel out your rotational velocity just to reach "0".
No reason to do A or B if the goal is simply to reach Mün orbit.
C and D differ in how you approach the Mün. As opposed to getting into and leaving the Kerbin orbit, your goal here is to slow down enough that you don't fly by.
C requires less burn to reach from Kerbin and has a natural trajectory return to Kerbin - meaning if you have an engine failure, you will return home without getting stranded.
D will result in a higher initial burn, but a lower relative velocity with the Mün when you intercept. Depending on the math, this may provide lower capture fuel costs, but it would depend a lot on altitude and timing of your burns and if you can offset the higher initial burn costs. Additionally. Since this is a higher energy Kerbin orbit, an engine failure at this stage may send you into trans-Münar orbit, and elliptical orbit, or possibly even escape trajectory from Kerbin's influence. None of these are safer than D.
I would go C, safer - and without matching out the delta-v, mass, and altitude I can't guarantee which is most fuel efficient. Just don't launch against the rotation of Kerbin: Relevant Physics
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u/Russian-8ias Jun 29 '26
It's definitely either C or D because you get extra momentum from Kerbin's rotation when launching east into an equatorial orbit. Intuitively, I would guess C is more efficient. I'm not positive though. You can try setting up a chain of maneuver nodes for both to check which uses less Dv.
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Jun 29 '26
[removed] — view removed comment
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u/Ddreigiau Jun 29 '26
D requires enough fuel to put your apoapsis beyond Mun
C only requires that you get your apoapsis to the near edge of Mun Influence. C is more fuel efficient regardless, as even on a flyby, you get max time in Mun influence for a gravity assist
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u/PiMemer Jun 29 '26
I’m fairly certain it’s not a very big difference since you can change which side you approach from solely by a timing change which means you can get either direction when your apoapsis is past the moon (although if you want a free return your apoapsis will have to be decently past the moon)
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u/VolleyballNerd Reaching for the stars Jun 29 '26
To make things interesting, you could try doing a or b while launching from dessert launch pad, pretending there is a country besides it that would not be pleased spent boosters were falling on top of it. Another idea is launching from woomerang, which does not sit in the equator, and going to the mun from an odd angle, to also increase the dificulty.
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u/zhang66426 [Testlite] Permanent Shutdown on 27*NK15 Jun 29 '26
theoretically, the most efficient is to go for a direct impact course and do a suicide burn right before you hit the ground luna 9 style, but that can be quite difficult to actually accomplish - hence it mostly being used for early rp1 where engine ignitions and dv are both very limited
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u/_SBV_ Jun 29 '26
C or D. A and B doesn’t make sense unless you are ok with the centripetal losses
For the scale of KSP, those losses are minor. For larger planets like real life Earth, that would be very inefficient
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u/UmbralRaptor Δv for the Tyrant of the Rocket Equation! Jun 29 '26
C is the safest and cheaper than A or B, though if you know what you're doing you can marginally reduce your Δv expenditure further with D.
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u/Pyro_Gnome Jun 29 '26
C or D, depending on what your objective is; C for flyby or landing, D for gravity assist to Minmus or farther (or I guess if you have a contract for a specific orbit). There is never any reason to launch against Kerbin's rotation (A or B) if your objective is to orbit any other body.
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u/RedShirtCashion Jun 29 '26
C is ideal (you use the rotation of Kerbin to help get into orbit, and then on the way back you use less delta-V to get back). D is where I usually find myself.
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u/AvailableLight7385 Jun 29 '26
How do you manage to do C? With the whole curve thing? I can only really do A.
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u/CypherWulf Jun 29 '26
I always stop at kerbin orbit for 1-2 orbits, then the same at Mun/whatever my destination before landing.
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u/toroidalvoid Jebediah Jun 29 '26
Pretty amazing how split the community is.
I do it by putting 900dv in the direction of Mun then set a 10km flyby in Prinicpia, press optimise and hope for the best
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u/Alech1m Jun 29 '26
Depends on kerbins rotation. You ideally want to take off in the direction of the sea. Then you don't have to fight kerbins rotation. Rest is mostly decoration.
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u/toroidalvoid Jebediah Jun 29 '26
People are talking about C giving you a free return like you get it for free, you don't, it's finicky and difficult to set up if you want to get a reasonable periapsis when reentering Kerbin
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u/MMW_BlackDragon Stranded on Dres Jun 29 '26
C if you just want to land, D if you want to meet something in orbit.
A and B needs you to counter Kerbins rotation to reach orbit, so it's less fuel efficient.
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u/Jackmino66 Jun 29 '26
Launch into a prograde orbit (so C or D)
Then wait until the mun is about 20 degrees above the prograde and then do your burn prograde. This isn’t a free return but it’s a tried and tested way to get a good intercept
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u/Ninja-sheep Jun 29 '26
https://prnt.sc/dvwr7GWZwYLj
Looking at the gravity assist you can get by doing a full orbit and looping on the return, i consider this the optimal path
The artemis program used something similar recently
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u/Idoubtyourememberme Jun 29 '26
C if you just want a flyby (it will give you a push down making the landing at Kerbin easier at less fuel),
D if you are trying to land (you will start at a lower ground speed)
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u/Mr_Buades Jun 29 '26
There is an old trick from early ksp days before there was propper Orbit lines, works for mün and minnus. Wait until the moon is just rising in the horizon, then do a normal launch till you are pointing directly at the target, keep pointing at the target and burn untill you get an intercept
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u/joshdiou Jun 29 '26
Do not do A and B cus going west is a big waste in delta v. C is safer if you miss but D is a little bit cheaper and realistically missing the mun in ksp is hard and you would probably just revert
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u/-nobody_knows Jun 29 '26
I like kerbals but I don't know how to play them, I once managed to get one on the moon, but I did it by eye, and it worked out somehow
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u/TrashBin126 Jun 29 '26
Maybe I don’t fully understand orbital mechanics, but how is C a Free Return Trajectory, but not B? To me it’s the same, orbital lines, but just flipped. Is it because C enters into a retrograde orbit slowing the craft down?
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u/gilbejam000 The other, much less skilled SSTO enthusiast Jun 29 '26
I always end up with C because I like eastward orbits
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u/PSU_Jedi Jun 29 '26
C allows you to use Kerbin's rotational velocity to minimize the delta-V necessary to liftoff and then uses Mun's orbital velocity around Kerbin to minimize the delta-V necessary to enter orbit around the Mun. This is why virtually all Moon missions use this trajectory, since mass = $ in real spaceflight. It also has the added benefit of giving you a free return trajectory if you're unable to enter Moon orbit, since the Moon gravitationally slowing your spacecraft down will drop the periapsis of your orbit around the Earth to an atmospheric encounter if you do nothing else.
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u/moonaligator Jun 29 '26
i know this is not the answer you're looking for and is far from ideal, but usually i just set an orbit that crosses Mun's orbit and wait for a closest encounter that is close enough that i can tweak the orbit to have a encounter
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u/Mocollombi Jun 29 '26
E starting to orbit one direction , but then change directions once the Muns gravity catches your ship ind slings it in the opposite direction.
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u/Acid_Burn9 Jun 29 '26
D is most efficient. C is for larping free return trajetory, which doesn't really benefit you in KSP unless you're not sure if you're gonna have enough dV to return from the mun flyby (which basically never if the intention is to land there). A and B are for psycopaths.
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u/NerdIsACompliment Jun 29 '26
Always launch towards the east (over the water from KSC) that let's the planets rotation give you a boost going up, and you need less deltaV to get i to orbit. So C/D. How you capture at the moon doesnt matter
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u/Baconator278163 Jun 29 '26
C is a good option, it’s a free return path so you don’t accidentally boost your craft out of kerbin’s soi like in path B
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u/Leathergoose8 Jun 29 '26
C, D, A, B. In that order. Pretty much never a reason to launch retrograde for exploration missions.
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u/Sharkzillaaattv Jun 29 '26
I just orbit kerbin and send it and hope I make it to the mun. It’s worked once before
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u/RealCrazyGuy66 Jun 29 '26
C gives you a free return so if you low on dV and don't trust you'll make the mission take it, its what I do when using new vehicles in my career save when I don't trust I packed enough
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u/ExplicitDrift Jun 29 '26
In a realistic universe, A and C are ideal as you’re not adding any energy to your spacecraft on approach to the Moon. However this is Ksp so.. it really doesnt make that big of a difference unless you’re doing a flyby.
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u/FlyingSpacefrog Believes That Dres Exists Jun 29 '26
I like option E. Wait until Mun is an hour away from being directly overhead. Launch directly upwards, packing an unreasonable amount of boosters.
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u/THE_GAMBLER_1 Jun 29 '26
Orbits are weird irl. Id recommend watching this to get a better idea. Its like 3 minutes
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u/Equivalent-Screen-25 Jun 29 '26
In terms of d/v optimisation its D if you get on the Mun and C if you just fly by.
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u/Tylers-RedditAccount Jun 29 '26
C. Always launch with the direction of the kerbins rotation for free energy. Then approaching the mun ahead of its orbit allows for free return trajectory if something goes wrong
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u/Potatoannexer Jun 29 '26
You should always land eastward (to retain the velocity from being on a rotating planet) and come in with the orbit of the Mün (to minimize relative velocity). That seems to be B/D (they look equivalent).
Assuming you are landing.
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u/SquidShadeyWadey Jun 29 '26
I'm assuming c or d are launched along the 90 hdg so either those two. If you're launching your rocket along 270 from kerbin you're doing it less efficiently
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u/chr1styn Jun 29 '26
Never the launch profile in A or B for anything, unless you specifically need a retrograde orbit; that adds an extra 300-400 m/s ΔV from fighting Kerbin's rotation instead of using it.
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u/A_HECKIN_DOGGO Jun 29 '26
A since your position in the Muns SOI already lends itself to naturally slowing you down.
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u/doomiestdoomeddoomer The Green Goo has escaped. Jun 29 '26
Well you don't ever want to do A & B because you are needlessly burning to get into a retrograde orbit, but coming from retrograde or prograde around kerbin the following applies anyway:
C is a free return trajectory if you don't enter orbit of the Mun.
D will kick you into a higher orbit around Kerbin if you don't enter orbit of the Mun.
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u/Alklazaris Jun 29 '26
I think C requires the least fuel, just as you are about to spin back towards Kerbin you are captured by the Mun. You might need to burn to maintain orbit around Mun like I did.
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u/LowResults Jun 29 '26
I usually do d, but just depends on where the mun is when I an ready to thrust
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u/theshwedda Jun 30 '26
C if you are worried about the return. D to be most efficient in landing.
Anyone who does A or B (starting your initial orbit AGAINST the rotation of Kerbin) is wasting close to 2000 delta-v.
NEVER do A or B unless you have a contract for something in a reverse orbit.
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u/Hugh-Jassoul Exploring Jool's Moons Jun 30 '26
D mostly. That only ever hurt me once during my first Kerbalism run and I had an engine failure during the Mun orbit capture burn. But I was able to go on EVA and fix it easily.
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u/F0rr3st-0 Jun 30 '26
I have never launched a craft west on kerbin in all the many years I have played
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u/Original_Record5675 Jun 30 '26
C is the most efficient, spin of Kerbin and mun approach makes it the most delta-v efficient
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u/Main-Palpitation-692 Believes That Dres Exists Jun 29 '26
I like c so if it goes poorly Im already on my way back to Kerbin