How you time your trip for catching the Mun???

[Kodiak]

When launching at 90° for intercepting the Mun, how do you figure out what is the right launching time WITHOUT MechJeb???

I always can make it to the Mun but always at a time the Mun is not there, LOL

So I have a large eleptic orbit then from Kerbin to the Mun but the Mun never there

How you guys do that? (without using MechJeb please)

Thanks in advance.

My best regards, Kodiak.

[Chewie]

I\'ve been wanting to know this too. I want to get their manually without MechJeb, but I\'ve noticed that even MechJeb won\'t get you to the Mun sometimes.

[Akaliwolf]

Err...I belive if your aiming at 90*, you burn when the Mun rises above the horizon :3 some one correct me if Im wrong some one.

[DonLorenzo]

Yep from about 70-150ish km altitude above kerbin the right time to burn is when the mun rises.

[Zephram Kerman]

This is one of the technical issues which occupied the brightest minds of Kerbin for several lunch meetings. Using much higher math, three slide-rules and a potato, the KSC engineers came up with a rule that is usually understandable by at least 1/3 of crewmembers:

When you see the Mun, punch it!

In other words, the Mun (and so far, in my experience, this also applies to Minmus) rising over the horizon happens at just the right time to assure a 'pretty good' trajectory for Trans-Munar Injection.

[xclusiv8]

I usually go with the well established technique of 'well this feels about right' =)

[maltesh]

Also keep in mind that, with the Munrise burn method, you will get out to the Mun\'s radius before the Mun gets there, but you will be moving slowly enough that the Mun will catch up and sweep you into its Sphere of Influence. The Mun\'s SOI is nearly 5000km across.

[Chewie]

So I waited for Munrise and then just burned to 12,000,000m. I was captured by the Mun but was on a parabolic escape orbit. I had to burn at Mun periapsis to get into a circular orbit.

Now to land...

[Kodiak]

Mkay, gonna try this out tomorrow.

Wish me luck! (and may God help us)

Thanks guys!

My best regards, Kodiak.

[jolee1868]

So this is my flight procedure to get to the mun and for me it works most of the time if I keep true to my headings and flight path.

Now everyone has their own method to Gettin a earth orbit.. Im no expert but I will launch full throttle straight up to 20-25km. At this point I will angle down the 90 degree heading to a 45 degree angle. I keep this heading until my peak altitude (I can remember off the top of my head periopsis or apopsis ) but around 100km. I cut power and drift to about 5km from that peak point. Then I will full throttle at a 0degree inclination on the 90degree heading still. Lookin at the map view I watch the flight path until it is the shape and altitude I want. Your velocity at this point should be about 2300m/sec to maintain your orbit but thats not a big deal if you aren\'t planning on staying there, we don\'t we are adventurers and the mun is on our mind. With throttle cut drift until you see the mun just crest earths horizon and full throttle at your yellow circle which is the direction of velocity. It should be right around the 0degree inclination point since you got into orbit in this direction. Also make sure you are at 90 degrees still. Watching map view control your ship until you see your trajectory intercept the mun. It is important you have the X key ready to immediately kill throttle when you intercept. If you intercept but over shoot before you kill throttle no big deal. Simply kill throttle, direct your ship to the yellow circle with an X to reverse burn. You don\'t need much throttle at all. Watch map view and stop when you intercept again. Now fast forward until you actually enter the orbit. This is where it is tricky. You will need to burn and reverse burn to get orbit. It takes practice and I can think of how to explain it.

That in short is my method of mun orbit and I can do it most of the time. You will develop your own procedure that works but I hope mine gets you started. Some things ive learned try keeping your 90 degree heading at precise as possible over time as you are off a few degrees it is magnified when you get to the mun. Your orbit will be different. Not a huge deal but it is something to think about. Good luck all.

O and if you keep burning out of earth orbit like I was explaining and burn past the mun you will intercept minimus as well. Thats how ive gotten there before. Just keep burning and watch the map.

[illectro]

Back when the Mun was added I did a bunch of math, carefully measured the angles and when I went to burn I noticed that the Mun was rising:

[N2maniac]

If you start in a low kerbin orbit and try to aim at the Mun with a single burn to raise the apoapsis to its orbit, you are looking for what angle to have you vs the Mun when you start the burn. I did some calculations for this and it seems the 90 deg mark that is often quoted is a bit off. My best explanation:

Looking from above, position yourself in the 6 o clock and the Mun in the 2 o clock position (rotate the camera/wait on your low orbit to come to it). From there do a prograde burn until apoapsis reaches the Mun\'s orbit. In v0.15, you should see the SoI change to know you got it right.

In other words, like this you will do 1/2 a rotation in the time it takes the Mun to do 1/6 a rotation (roughly)

Example:

Once you see the SoI change you can figure out what corrections you need to do. My advice is wait until you are 1/3 to 1/2 of the way there since it does not work very well to adjust your course near kerbin (unless it is an arrival timing).

[maltesh]

The off-claimed 90-degrees most likely comes from a misconception that the visual edge of Kerbin is horizontally in front of you at ~100km altitude. It isn\'t. It\'s about 31 degrees below horizontal. So when the Mun rises, it\'s about 59 degrees away from where your apoapsis would be if you started burning right then.

An object in an orbit whose radius is your apoapsis will travel about 63 degrees along its orbit in your travel time from periapsis to apoapsis when your apoapsis is far higher than your periapsis (such as when you\'re heading from LKO to the Mun or Minmus)

And since the Munar SOI is a bloody huge target, and Kepler\'s second law means that you\'ll be hanging out at Apoapsis for quite some time, the Munrise Burn method works.

[White Owl]

I read somewhere that it was best to aim for a spot about 60 degrees ahead of the Mun, so I just eyeball it that way.

[N2maniac]

The off-claimed 90-degrees most likely comes from a misconception that the visual edge of Kerbin is horizontally in front of you at ~100km altitude. It isn\'t. It\'s about 31 degrees below horizontal. So when the Mun rises, it\'s about 59 degrees away from where your apoapsis would be if you started burning right then.

An object in an orbit whose radius is your apoapsis will travel about 63 degrees along its orbit in your travel time from periapsis to apoapsis when your apoapsis is far higher than your periapsis (such as when you\'re heading from LKO to the Mun or Minmus)

And since the Munar SOI is a bloody huge target, and Kepler\'s second law means that you\'ll be hanging out at Apoapsis for quite some time, the Munrise Burn method works.

Wow, suddenly it makes sense. That would just about match what I have found angle-wise.

[Vespasianus]

Why does everybody turn 90 degrees? I turn 270 degrees, and I hit the mun almost every time. Are there any advantages of turning 90 degrees?

[maltesh]

Why does everybody turn 90 degrees? I turn 270 degrees, and I hit the mun almost every time. Are there any advantages of turning 90 degrees?

The Munrise Burn method (get into an Eastward Orbit (090), wait for the Mun to rise, burn to raise your apoapsis, coast and capture) has benefits of both costing you less fuel, and taking less time.

The method I like to call 'Wrong Way Charlie' would be to get into an equatorial westward orbit (270), pushing your apoapsis to the Mun\'s altitude,then circularizing and waiting to come into the Mun head on, has a lot of built-in fuel penalties.

When you take off eastward, you get about 200 m/s free orbital velocity from Kerbin\'s rotation. WWC means you not only don\'t get the free velocity, but you have to fight the planet\'s rotation velocity. So you\'re 400 m/s behind.

If you get to the Mun\'s orbit on a Munrise burn and the Mun\'s there, your relative velocity to the Mun is about 250 m/s on a Munrise Burn.

On a WWC, if the Mun\'s there, it\'s about 750 m/s. If the Mun isn\'t there and you had to circularize (costing you another 250 m/s in delta-V) your relative velocity is about 1100 m/s, and it could take as long as half the Mun\'s period to get into its SOI Regardless of how you got into the Munar SOI, you\'re going to have to slow to near zero relative to the Mun if you\'re going to land.

So if you do a WWC ascent to the Mun, you\'ve got to spend between 900 m/s and 1400 m/s of extra Delta-V to go from Kerbin Surface to a Mun landing. Most people\'s Mun rockets could probably do that, but 1400 m/s of extra delta V spent getting there means less fuel for maneuvering and landing when you arrive.

[Vespasianus]

Oh, I didn\'t know that. I think I\'ll turn east next time Thanks.

[SubOrbitalGuy]

I use the 90 degree heading for a 160 km starting orbit, that way I can use the higher time warp.

Burn for mun starts when it just had risen completely above the horizon, for an apoapsis of about 10500 km.

If you do it this way it looks like you are very far in front of the mun close to apoapsis but it will catch up and you will be pretty slow relative to it so you don\'t need much fuel.

[E. F. Kranz]

I\'m a simple person. Hell, I couldn\'t even read the whole thread.

But I hit the moon every single time I try. Period.

Just deal with the map view. If you\'re a decent pilot, you should be able to complete the ENTIRE MISSION inside map view.

Circularize an orbit around the planet.

Realize that your travel time to the moon is roughly the same time it takes the moon to traverse 1/4, or 90 degrees, of its own orbit.

So, your lunar burn should begin when you are 180 degrees opposite of where the moon WILL be when you get there, which is 90 degrees away from where it is now.

As to a heading of 90 or 270, it\'s really irrelevant. Your craft should be designed to reach planetary orbit first, and lunar injection second.

At least for me, absolutely no math is required. I fly by the seat of my pants, and I rarely miss. Keep in mind that your orbit, as it stretches out towards the moon, requires less and less delta-v. Throttle down considerably as the orbit projection approaches the moon\'s orbit. RCS might be useful to fine-tune your periapsis based on strategy and fuel requirements.

Prior to the new system, it was much, much more difficult. My system doesn\'t fail, unless you fail it.

[Menelmacar]

E.F Kranz I\'d like to ask (politely) how you land on the Mun in map view, how do you do that when the altimeter doesn\'t show distance to surface?

Bear in mind some people are new and don\'t know how to circularise an orbit, or that they\'re just wasting fuel heading west from Kerbin unless their mission requires it.

[shhhilent1]

I go 90 degrees, get a 100km by 100km orbit, and when the mun rises, i burn prograde.

thats the easy way to get to the mun.

(and the patched conics)

[E. F. Kranz]

E.F Kranz I\'d like to ask (politely) how you land on the Mun in map view, how do you do that when the altimeter doesn\'t show distance to surface?

Alright, well in truth I\'ve never done that. I think there are mods for ground radar, but I don\'t use them (or mechjeb, or anything else).

Sounds like a good challenge though. I suppose if you knew the height of the particular spot you were landing, it wouldn\'t be too difficult. (BRB - Damn, thanks for stealing my evening!)

Bear in mind some people are new and don\'t know how to circularise an orbit, or that they\'re just wasting fuel heading west from Kerbin unless their mission requires it.

I\'ll take your word on wasting fuel going west. Using my guesstimation method, there\'s positively no reason that you couldn\'t go due north and still intercept the moon. On the other hand, I\'m also certain that my building style is often inefficient. Since KSP is currently a sandbox game, for serious missions I tend to build in ridiculous levels of redundancy and extra fuel.

[hunter558]

You can wait for the mun to rise or just burn at 90 once you reach about 70k until the apoapsis reaches the mun\'s orbital path and then just warp around on your orbit until you come to a mun encounter or collision course with the mun. At which point your gonna want to burn retrograde at varying intervals until you land. Thats what i do anyways and im not pro but it gets me to where im going(Mun, Minmus, and Kerbin if the need be).

[shhhilent1]

E.F Kranz I\'d like to ask (politely) how you land on the Mun in map view, how do you do that when the altimeter doesn\'t show distance to surface?

Bear in mind some people are new and don\'t know how to circularise an orbit, or that they\'re just wasting fuel heading west from Kerbin unless their mission requires it.

Um for some reason, the replies your post didnt show untill i entered here, forum getting glitchy?