Munlanding, almost but not quite

[Zambaku]

I've gotten a lot better now thanks to MechJeb and some lessons on rocket building. I can make it to mun with no problems and I can now do an orbit which is a big step for me. I did the orbit and decided this time I would not crash. Once in a stable orbit I told MechJeb to pick a landingspot and initiate. He did just that and things went well, untill we got close to Mun, Mechjeb's brilliant plan was to suicide dive down then do a retroburn at the surface with all his might, but we still crashed like so many times before. Where my engines not powerful enough? On my lander I'm using 4 Mk-55 "thud's".

This is my landing module on it's way to space:

And this is my whole Mun rocket:

[Scarecrow88]

I've never used Mechjeb so have no idea how it executes a landing procedure, but your lander looks like it should be able to land without problem.

[Sharpy]

Four thuds are an overkill which makes lunar landing difficult because they are overpowered for this purpose.

I don't know about MechJeb, but I know for a fact KER gives you a suicide burn amount for vertical landing - not diagonal at considerable speed. Instead of "clean" suicide burn, perform the burn some 1000m short of the optimal goal, reducing your speed to 30m/s or so. Then perform another 100m short of the surface with some 20m/s target, then another 10m above the surface, stopping dead, and finally descend on the engines set to such a power that you have a safe descent speed. True suicide burn is a nice theory that in reality usually ends in its namesake. Sure it's "optimal" if you count your lander scattered over half of the Mun optimal.

[tater]

Yeah, that thing would land easily with a single 909. I don't use those engines much, but my guess is that 4 of them would be fine for a 3.75m tank.

[bigcalm]

It's hard to tell from the pics, but I suspect your problem is one of control, not one of power - try adding a reaction wheel, preferably somewhere around the centre of mass (but not totally essential). Try to avoid craters on the Mun when landing as some of them are pretty steep, but your craft should be squat enough to cope regardless.

[Evanitis]

Strange. Landing guidance is one of the features of MJ that I feel I have no chance of beating manually in efficiency.

My only problem with is was when the ship wasn't controled from the pod I though it was, so MJ confused the directions. But I don't think that's the case with your craft - it looks ok on that screen.

The autopilot should do the landing just as you described - besides the very end. A scary fast descent and a last-second burn. You didn't change the 'touchdown speed' value of the landing guidance by chance, right? Not sure what's the default number there, but if you see a two digit one, try lowering it. If that doesn't help I can only assist further if you upload the craft-file.

Unless someone spots something on those two screenshots that I missed.

[Superfluous J]

At the very least, cut it down to 2 Thuds. Or better, a single Terrier. You'll go farther and have more control. One other bonus of the single Terrier design: If you still have too much power, you can thrust limit it easily. Try doing that with 4 Thuds while trying to maintain a hover 30 meters off the ground.

[Kryxal]

I'd say a quick-fix for the craft currently in orbit (if you saved it) is to turn off two of the engines ... but that really IS overkill and far more mass than you need to take with you. A TWR of 1.5 is easily enough to land, 5 makes near-suicide burns easy (this is LOCAL TWR, not Kerbin-relative) but this is probably more like 20.

[Zambaku]

I added a reaction wheel and changed the thuds for 1 terrier. And I'll upload the ship for you to examine. In the meantime I'm going to do a test run myself.

Here is the ship:

http://www.filedropper.com/munlanderexpress

[Zambaku]

We did it! Seelas Kerman is the first kerbal on Mun! The way I did it was I de-selected auto-warp for the landing. Seems that is fatal to have on. However we have one small issue...My ladder isn't long enough for him/her to reach!

- - - Updated - - -

I just remebered I had a jetpack, haha, I was so excited I forgot about that. Well, I'm in Mun Orbit once again, with very little fuel, can I make it back home? What is the best way to get back home, Hohmann sling?

[xtoro]

MechJeb has an option in the maneuver planner called "return from a moon" which will plot it for you. But if you want to do it manually, you need to setup a node which will let you escape the moon's SOI in the opposite direction of the moon's travel. If your orbit is counter-clock wise around the moon, setup a prograde burn closest to Kerbin. If your orbit is clockwise, then setup a prograde burn furthest from Kerbin.

[Kryxal]

One thing I ALWAYS have up when using Mechjeb is the delta-v stats. Use that and you'll know if you're good to return, in combination with "return from a moon". Incidentally, if you use the created node, take a look at your periapsis first and adjust the burn as needed (35-40 km is very safe, 30 is probably ok, plowing into the ground is generally bad).

[Scarecrow88]

Best way home from Mun is to burn prograde when Kerbin is just above the horizon. If you burn until your periapsis at Kerbin is about 35000 - 37000m this should be enough to guarantee aerocapture in to Kerbin orbit. You only need a relatively small amount of dV to do that, and you look as if you have enough fuel left for such a burn.

[DCWarHound]

Your first craft is a bit overkill.My mid game Mun and Minmus craft are usually like this :

Lander has exactly 0.30 TWR in Kerbin Atmosphere,if it is below that then dump some fuel,if it's more then add some fuel.

Center has around 1.20 TWR in Kerbin atmosphere

Radials also have around 1.20 TWR in Kerbin atmosphere however the catch is that they feed fuel to the center stage via fuel ducts and the center and radials are both turned on at launch.As a result you can put allot of spare fuel in the radials and the center won't start using fuel until the radials are detached.

I rarely use boosters but they usually have a TWR above 2.0.

[Warzouz]

Good job for you first landing on Mun.

MJ is a great help, but it can do things very wrong. As for auto landing, beware of the "auto-warp" feature : it usually come out of warp too late and crash. KER can also have bad readings on suicid burns.

On you first few trips, don't be afraid to oversize and do some unefficient landing (controlling you speed on high altitude instead of suicid burns). Use MJ on final touch down (few 100m) if you're not easy with it.

Also, even if you succeeded, don't hesitate to reload and retry to be better at it. Many KSP bodies are nearly as the Mun (Moho, Mun, Ike, Dres, Eeloo, Vall or even Duna) and some are even easier (Gilly, Minmus, Bop, Pol), few need specific landers (Eve, Tylo, Laythe, Kerbin).

In the end, the hardest part of landing is to avoid landing on a too steep slope and flip. Designing a large and flat lander will reduce the risk of flipping.

Edited July 20, 2015 by Warzouz

[Wemb]

We did it!

Woot! - To get home, as other have said, watch what MJ does - but another way to think about it is this:

You're okay at doing a Hohmann transfer to change between two circular orbits right? So, now imagine you're needing to do a similar transfer go travel from the orbit of the Mun to a Low Kerbal Orbit (even if don't intend to circularise when you're back at Kerbin) - you do it the same way - burn retrograde from your existing slow wide orbit to get into a smaller, faster orbit. The complication here is that you're orbiting both Kerbin and the Mun together - so you need to decide when, during your Mun orbit is the best time to leave to do the Hohmann transfer to Kerbin.

As you want to burn retrograde (with respect to the Mun's orbit around Kerbin) your best time to departure would be (assuming you're orbitting the Mun counterclockwise) when you're coming back around the front of the Mun with you directly between the Mun and Kerbin which is when you're flying the opposite direction to that which the Mun is going around Kerbin.

Get this sorted in your head and you're well on your way to working out how to do inter-planetary flight.

Wemb

[Padishar]

If you have manoeuvre nodes then create a prograde burn to escape mun orbit and move it around the orbit to see the effect the position has on what happens. You want to be leaving the Mun's SOI going retrograde to the Mun's orbit direction, this results in a slower orbital speed than the Mun so your periapsis around Kerbin will be lower than Mun's. If you burn enough you can easily get your Pe into the atmosphere but you may need to experiment with your Pe altitude to avoid heat issues during re-entry (you will be going quite a bit faster than when returning from LKO). If you haven't got manoeuvre nodes then you will have to pick the direction by eye (or have play with a manoeuvre node in sandbox mode or one of the tutorials), looking from above (orbits anti-clockwise) when Kerbin is at the top of screen, you want to burn when you are at about 1 or 2 o'clock around Mun.

Edit: whoops, didn't see the second page...