MechJeb help! Wont land on the Mun.

[Raikzun]

Hello.

First of all. I've been following this guide: http://wiki.kerbalspaceprogram.com/wiki/Tutorial:Moon_landing_using_mods

Going into Earth orbit works no problem.

After you enter the Mun's Gravity well, wait until you reach around 400 km above the Mun, then use the arrows to select 'Circularize' and click 'Create and execute'. This will put you in the Mun orbit.

This doesnt work. Whenever i press on the Circularize it says i have no aposis point or something. Then i set it to "by altitude" instead, and set it to 400km. Works fine. Orbiting the mun.

[h=3]Step 4 - Land on the Mun[/h]

• After you entered the Mun orbit, open the Landing Autopilot from the MechJeb menu.
  
• Ensure "Deploy Parachutes" is UNchecked.
  
• Press Select target on the map and choose where you want to land.
  
• Press LAND at target.
  
• MechJeb will fast forward to the deorbit burn point.
  
• Warp till 20000m (don't warp more than 3x).
  
• Extend the gear once it says executing breaking burn.
  

You have now landed on the moon. You can extend the ladder and EVA(optional). Follow step 5 to return to Kerbin.

I follow this completely, and i just crash into the mun.

[kerbanoid]

This doesnt work. Whenever i press on the Circularize it says i have no aposis point or something. Then i set it to "by altitude" instead, and set it to 400km. Works fine. Orbiting the mun.

You probably left the apoapsis option selected on the circularize maneuver, but there is no apoapsis because you are following a hyperbolic trajectory. You should circularize at the periapsis.

I follow this completely, and i just crash into the mun.

Why are you crashing? Are you running out of fuel or you are not able to deaccelerate fast enough? I guess the problem is your 400km orbit, you should have a much lower circular orbit around Mun when going for landing, something like 20km or even less. Landing directly from such a high orbit is not really fuel efficient, and you have to take care when to start your suicide burn. Maybe starting it at 20000 km is not enough given your twr.

Hope this helps!

[Raikzun]

You probably left the apoapsis option selected on the circularize maneuver, but there is no apoapsis because you are following a hyperbolic trajectory. You should circularize at the periapsis.

I set it to cricularize at the periapsis, like the periapsis is inside the moon lol..

Why are you crashing? Are you running out of fuel or you are not able to deaccelerate fast enough? I guess the problem is your 400km orbit, you should have a much lower circular orbit around Mun when going for landing, something like 20km or even less. Landing directly from such a high orbit is not really fuel efficient, and you have to take care when to start your suicide burn. Maybe starting it at 20000 km is not enough given your twr.

Hope this helps!

Im not able to deaccelerate fast enought.

I'll try with a lower orbit as we speak.

*EDIT*

Figured it out.

The crashing occured because i ran out of fuel LOL..

The landing is still a bit sketchy. i land like on the sites, and not on my landing gear xD ..

I will learn over time. Thanks for your help!

Edited September 30, 2015 by Raikzun

[kerbanoid]

You can use the delta V readings from MechJeb to help you calculate how "far" your rocket can go and avoid running out of fuel. A round trip to the surface of the Mun, for example, requires around 7000 m/s.