Minmus Landing

[Garu1304]

So, I can get to Minmus, I can land on Minmus, I have all required skills. My only problem is completely killing horizontal velocity. I can get the first part of the descent to have no horizontal velocity, but then I began descending, and I reduce my speed every so often, and the horizontal velocity increases. So my question is, how do I never have horizontal velocity on the way down? Thanks for your help.

[Scotius]

Minmus rotates fast. When you are high above surface, relative velocity is small. Lower you get, relative velocity increases. You have to counter it by angling thrust vector to not only lower your ship, but also to stay over one spot on the ground.

[rpayne88]

Its from the rotation of Minmus. I'm assuming your killing all horizontal velocity in orbit and letting yourself fall to the surface. The easiest way to land is to follow the retrograde vector all the way down. Complete a de-orbit burn. The wider the suborbital arc, the more efficient your landing will be as you will be left with very little vertical velocity to kill. It takes practice to get right, but if you follow the vector, you will land with zero horizontal velocity.

[N_Molson]

I'm not sure I'm completely getting it, but one of the best way to kill horizontal velocity is to keep your ship pointed to the retrograde marker (the circle with a cross on the ADI ball). On Minmus you need to apply a very tiny amount of thrust, else you'll also kill all your vertical velocity.

Else just fly the lander like an helicopter. Pitch down : accelerate ; pitch up : decelerate ; pitch left/right : lateral translation. And adjust the throttle constantly.

[Garu1304]

Okay, so what if we were talking about the mun? then how would I land with zero horizontal velocity if I was having the same problem as described above?

[Coneshot]

I generally just stay on the retrograde marker on the way down and it takes care of itself. If I'm getting low and it's not coming up fast enough, I'll go a little below the retrograde marker(between it and the horizon line) to speed it up a bit.

[MrPopcup]

Look, if I understood you well, your making your burn way too much, both of them have low gravity, specially minmus, what you need to do is this ->

say your in 80x75km orbit, and you want to get down, make a maneuver node and make the periapses ( sorry if I spelled it wrong ) go down to 5 or 8 km ( above your target ) then when you reach 10 km, start killing horizontal velocity by following the retro-grade marker ( the one with dot in the middle ) you should see it going slowly up to the center, let it go to the center but keep you velocity low ( say ~ 10m/s ) then once you started 'seeing' your shadow start slowing down to 3m/s, you can tell your height by the shadow, once you see the shadow really close, thrust up a little and make it reach 1~2 m/s ( although 3m/s is pretty good to land with ) but just to make it better and safer, then you'll touch down and boom, you landed without horizontal velocity ! ( a tip: always turn of your engine when you land, you may thrust up by accident and loose everything you did. )

Edited July 27, 2013 by MrPopcup

[Scotius]

And best kind of lander is a squat, low contraption with widely spread landing legs. Keeping Center of Mass (CoM) low also helps - tall or top heavy rockets tend to wobble and sway dangerously when you are trying to kill the horizontal velocity with main engine.

[Kegereneku]

In simple term landing mean Reaching your destination and then Stop here.

What you have to do everywhere :

- Burn so that your trajectory pass anywhere closer to the target.

- Wait to get closer and burn retrograde to reduce speed.

"Repeat Ad Infinitum"

If you have a low acceleration : Do it more often. (but check if your engine actually allow you to land (TWR > 1))

I know it sound ridiculously simplistic, but you'll learn the subtlety (like hitting mountain and aerobraking) while doing exactly that.

Edited July 27, 2013 by Kegereneku