Question Regarding Mechjeb

[Antuas]

This is my first post here so you'll have to forgive me if it's in the wrong area. My problem is that I have a ship in orbit and I wanted to try to land on Mun. I go to the rendezvous planner and it says please select a target. I set target as Mun and nothing. The screen doesn't change and still wants me to select a target. I tried unselecting and reselecting but nothing happened. I'm pretty new to KSP and mechjeb so a little help would be appreciated.

[AeroAviation]

You must go to the maneuver planner and select the Hohmann transfer to target, it should plot a course to the mun but pull the node back retrograde unless you want to crash land.

[astropapi1]

I think you need to select "Hohmann transfer to target" for it to work.

But you know what? Even as an avid mechjeb user, I think you shouldn't be doing that kind of stuff at first. Watch tutorials, experiment, explore, do stuff on your own. Doing things on your own at first is one hell of an experience, and understanding how to get to the Mun on your own will help you a lot when you want to rendezvous with a station or another planetary body. My suggestion? Just do it yourself until you know what mechjeb is doing.

Going to the Mun is pretty simple anyway. Just place a maneuver node on your orbit (equatorial and circular) and drag the prograde marker until it reaches the Mun's orbit. Then simply drag the node itself along your orbit until you intercept the Mun.

You can also go old school and start burning as soon as you see the Mun on the horizon. It should get you there pretty accurately.

Here's a Scott Manley video:

[EdFred]

This is my first post here so you'll have to forgive me if it's in the wrong area. My problem is that I have a ship in orbit and I wanted to try to land on Mun. I go to the rendezvous planner and it says please select a target. I set target as Mun and nothing. The screen doesn't change and still wants me to select a target. I tried unselecting and reselecting but nothing happened. I'm pretty new to KSP and mechjeb so a little help would be appreciated.

If you are in orbit around the Mun you cannot set Mun as your target.

If you are in orbit around Kerbin, select Mun as your target, and then Hohmann transfer under maneuver planner. Once in the Muns SOI, under maneuver planner change your periapsis to something like 20km 0s from now. Then under maneuver planner circularize orbit at the next periapsis. Once in orbit around the Mun under Landing Guidance, select pick target on map, and after selecting click Land at Target. You will want to pick a spot at least 1/2 an orbit ahead of your current position.

If already in orbit around the Mun just do the above starting at Landing Guidance

[Wanderfound]

As above.

However, for a bit more detail on ye olde low-tech way to do it:

* Get into a circular equatorial orbit of Kerbin. 70km is the minimum altitude, but it doesn't matter if you're at 100km or whatever.

* Point the ship prograde and wait for Munrise.

* When you see the Mun, start burning at full throttle and keep doing it until you get a Mun encounter (visible in the map screen). Keep the ship pointed prograde the whole time.

* Once you get the encounter, stop burning immediately.

* Timewarp until your ship enters the Munar SOI. Again, you can see this happen on the map screen.

* Just before Munar periapsis, burn retrograde to slow yourself into a Munar orbit.

* Adjust your Munar orbit however you like, the same as you would while orbiting Kerbin. There's no atmosphere to worry about, but keep your periapsis above 8km unless you feel like orbiting into the side of a mountain.

* Descend and land. This is the bit that you'll probably have most trouble with, although as with most things in KSP, it's easy once you figure out how to do it.

[Starman4308]

Hohmann transfer is what you're looking for. One thing which wasn't well-explained is that, by default, MechJeb will transfer you straight at the target, which is useful for rendezvous, but not useful for lunar injection, because your target orbit will send you plummeting straight for the center of the Mun. You will need to edit the maneuver node: a low-velocity, later burn will get you an efficient cis-lunar insertion, while an earlier, more powerful burn will get you a trans-lunar insertion. A special case of trans-lunar insertion is the free-return trajectory, which will send you on a figure-8 around the Mun and back into Kerbin's atmosphere; the first Apollo missions did this, so that if the Service Module's engine didn't ignite, it would simply return to Earth. It also makes a wonderfully efficient lunar flyby trajectory.

Regardless of whether or not you use Mechjeb to set up the initial transfer, I would still recommend playing with the maneuver node to see what effects various modifications to the burn have on your trajectory, and try to figure out why those happen.

[Antuas]

Okay, I've encounter a new problem. Mechjeb won't circularize my orbit. It does just fine getting into space and drifting, then it says circularizing but the engines don't ignite. It just floats there until losing altitude.

[Wanderfound]

Okay, I've encounter a new problem. Mechjeb won't circularize my orbit. It does just fine getting into space and drifting, then it says circularizing but the engines don't ignite. It just floats there until losing altitude.

Check the resources tab. Most likely, you're out of electricity. If so: batteries and solar panels. Or turn off MJ; it consumes power.

[panzer1b]

I remember the days i tried to do this, way back in .22.....

Now i dont even use MJ, whats the fun in autopmating everything, if i just wanna get to x location i bloody teleport there and dont even bother with MJ, which btw isnt too efficient when it comes to many maneuvers (rendezvous takes more dV then u need often, docking eats RCS like nothing, ect ect ect).