Problem Reducing Speed On Mun Landing.

[Grindcore]

I have tried landing on the mun several times with no luck, it seems that i cannot get my speed under 35 m/s when approaching the surface. Any help is appreciated.

Edited July 14, 2013 by Grindcore

[UtopiaV1]

Best read this thread, contains a video with the most efficient landing technique (for none-atmospheric conditions) - http://forum.kerbalspaceprogram.com/showthread.php/39999-Maximise-Landing-efficiency

[rioburrage]

More rockets!!!

[SRV Ron]

Could be you don't have enough thrust to slow down and hover. Balanced thrusters are useful for killing horizontal speed and avoiding boulders in the final approach. Got a small probe down on my second attempt using thrusters alone after staging the descent rocket. Note, the altimeter doesn't read surface distance. Either land in daylight and watch for the shadow of the lander, or use radar from inside a manned lander.

Then again, you might be getting a surface speed measurement in addition to a descent speed thus confusing you to the actual descent speed.

[Temeter]

Can you show us pictures of your lander? That will get you the best answers.

[Grindcore]

Here is a picture of the spacecraft that i have been using to reach the mun.

As well as a picture of my approach.

[medikohl]

you might need more thrust by the look of it. I'd suggest adding in some of the tiny radial engines. just my two cents

[medikohl]

alternatively you might have too much horizontal velocity.

[kahlzun]

keep in mind the orbital and surface speeds are different; the mun spins, and your suicide burn has zero horizonal relation to orbit, not surface..

[medikohl]

you can change the speed indicator by clicking the spot right above the nav ball.

So you can switch between orbital, surface, and target velocities at will.

[Grindcore]

It is most definitely my horizontal velocity, i have been able to almost land several times since posting this topic but keep tipping the lander due to high horizontal velocity. I am unable to correct this even with watching various videos and reading various articles.

[SRV Ron]

Looks like more then enough thrust for landing. It is horizontal speed confusing your landing that you can control with thrusters using the translation keys. But, I would start the final, suicide, decent from say 5,000 meters then from so high up.

The 4 engines should go to near the base, instruments higher up, and thruster pack just above the center of mass. Lose the tiny thruster tanks. You have plenty of fuel in the big one. Design is also top heavy for landing.

Edited July 14, 2013 by SRV Ron

[Grindcore]

I just managed to land it, im going to do another run at it to see if it was a fluke or not, most of what was said was a big help to my landing though.

[SRV Ron]

Congratulations! Next step, return to Kerbal. Do an escape burn towards Kerbal. Once in Kerbal orbit, aim for a paragee window of 15,000 meters and let aerobraking brings your Kerbals safely home.

[Grindcore]

I still can't seem to figure it out, i just did another run to the mun but couldn't get it to land, my spacecraft just wont stay up right, as someone stated its top heavy and i believe this is where the majority of my issues are coming from.

[DocLangy]

I've had tha same issue. I started opting for more of a skycrane type lander. I'll see if I can get some screenshots

[Grindcore]

Please do.

[Johnno]

I still can't seem to figure it out, i just did another run to the mun but couldn't get it to land, my spacecraft just wont stay up right, as someone stated its top heavy and i believe this is where the majority of my issues are coming from.

I copied the design and sent it to Mün for a testrun. I burned hard retrograde and then did a straight down landing from about 40km, which all in all is quite demanding on the fuel supply (ie inefficient). Landed fine, got back into orbit, even made it all the way back to Kerbin safely.

Designwise as such there's a lot to improve on, but other than that it works fine, I think you just need more landing practice. Keep an eye on your navball, get your retrograde marker to the middle of the blue on the navball (so you're heading straight down) then just keep an eye on your descent rate. You can use RCS to translate and kill your horizontal speed using IJKL keys in staging mode, but for the most part of your descent just tilt the lander in the same direction your retrograde marker veers off to until it's back to middle. Try to land with less than 5 m/s speed.

Design suggestions:

Put a decoupler below your pod to drop everything else before deploying your parachute. The ASAS ring is weak enough to actually detatch everything when your chute deploys, but I wouldn't take the risk.

You're carrying way too much RCS fuel. You can drop the large tank, the small radial tanks are more than enough for course corrections and landing help. Pod torque is enough to turn so you don't really even need RCS unless you're docking.

You don't need that many batteries either, I didn't see any power source but you could stick on a RTG or solar panel.

Beyond that you could downgrade the fueltank to a X200-16 if you swap the engines for a poodle, while removing the large RCS tank.

Hope that helps.

[Vanamonde]

480 thrust is PLENTY for a Mun landing, even though that lander is bigger than it needs to be for the job. It is top-heavy as well, what with the big RCS tank sitting up high. But you should still be able to land it by simply shedding more of your horizontal speed while landing. Either brake harder high up, or point your nose below the retrograde marker on your approach burn, which will increase the fraction of thrust being applied against your horizontal speed. But just as a suggestion, a low, wide lander will be much more stable and resistant to flipping. As an example, here is my standard Mun lander that I've been using for many versions now.

[Skorpychan]

Your lander is very heavy, and you're packing WAY more RCS than you really need.

Once you encounter the mun, burn retrograde until you got sub-orbital, then flick the speed indicator to 'surface' by clicking on it. Then burn retrograde until your orbit path goes nice and vertical. Cut thrust.

Time warp down to about 10k meters up, and apply a little thrust to start decelerating. Lower the landing legs nice and early, point the camera towards the surface, and get to a speed of about 200 m/s for now. Slow more as you get closer, so you're going about 10 m/s as you get close. Keep it that way until you get REALLY close, then slow further. Try not to hover, and cut thrust just before impact.

RCS and ASAS will cancel out the last bit of horizontal velocity once you're down.

[Grindcore]

Through trial and error, disaster after disaster i have made it onto the surface on my first attempt today. Thank you for all of your help, it was detrimental to my progression in space exploration! i will be moving on to bigger and better things! Wish me luck fellow cosmonauts.

*EDIT*

Now i just have to figure out how to land efficiently so i can get home

[Johnno]

Now i just have to figure out how to land efficiently so i can get home

You must've misunderstood my post. Remove ALL of the radial engines if you put a poodle on. THEN you can swap out for a smaller tank.

[Sathurn]

Burn retrograde until retrograde is straight up.

[Skorpychan]

I suggest simply using four of the little Rockomax radial engines. More power and lighter weight than the -909 engine, which in turn has a better thrust to weight ratio than the Poodle. And it allows for a completely flat bottom to the craft; helpful if you're hard on the landing legs.

Burn retrograde until retrograde is straight up.

This too. Use the retrograde marker to indicate speed across the surface when the speed is set to surface rather than orbital.

[jbaltus123]

i have this too!