Whats the needed Delta-V to get to the mun/minmus and how does one land on them

[jackboy900]

I've built a rocket to land on the mun but the landing failed. The lander is two of the FL-T200 tanks ,a science junior ,3 mystery goos ,a MK1 pod some batteries and panels 3 landing legs and an LV-909

Edited September 20, 2014 by jackboy900

[Simes]

From your description, I'd say that the problem is that you don't have any engines or landing legs.

A screenshot of your lander would probably help, along with one of the full craft in the VAB before launch. Also some more information on *how* the landing failed.

[FennexFox]

http://lmgtfy.com/?q=ksp+delta+v+map

it doesn`t take more then 3 seconds.

[cantab]

It's generally easier to establish orbit around the Mun first, rather than trying to land directly from your inbound trajectory.

Then select a landing site, preferably somewhere that looks flat. Make a small deorbit burn somewhere between 90 and 180 degrees ahead of that, lowering your orbit so it about touches the surface where you want to land. Watch out for mountains that might be in the way!

When you approach your landing site, put the navball in surface mode (click the speed) and burn hard retrograde to reduce your horizontal speed to near zero. The closer to the surface you do this the more efficient but riskier your landing.

Finally descend keeping your trajectory vertical and controlling your speed. In stock its hard to judge your altitude over terrain, the regular altimeter gives altitude over "sea level", but you can use your shadow or enter IVA view and use the radar altimeter. Or on Minmus the big flat areas are at sea level. With a mod such as KER or VOID that reports your altitude over terrain landings are much easier.

When you touch down cut the throrrle with x and be ready on the controls to ensure the lander doesn't tip over.

[Kasuha]

Perhaps try watching some videos which describe how to do it:

[EtherDragon]

I've built a rocket to land on the mun but the landing failed. The lander is two of the FL-T200 tanks ,a science junior ,3 mystery goos ,a MK1 pod some batteries and panels

In my Let's Play (Hardcore) this rocket, used in

, was able to land on the Mun with plenty of fuel to spare.

I used the same rocket, in

and

to land on several landing sites around Minmas in a single mission.

[Rusty6899]

http://lmgtfy.com/?q=ksp+delta+v+map

it doesn`t take more then 3 seconds.

Although it is extremely satisfying to use that website, I think that this forum is generally "above" such behaviour.

[SunChaser]

Minmus was my first destination outside of Kerbin's SOI. It takes far less d-v to orbit and land and due to the low gravity, a little Monopropellant goes a long way there. You can very easily de-orbit, land, and esacpe Minmus using RCS, or even EVA fuel if you lose an engine.

[Pecan]

I've built a rocket to land on the mun but the landing failed. The lander is two of the FL-T200 tanks ,a science junior ,3 mystery goos ,a MK1 pod some batteries and panels

Minmus 1,610m/s, Mun 1,750m/s. That would be Chapter 5 of the tutorial in my signature, where two ship designs for Minmus/Mun missions are also given. Note that Minmus is an easier mission than Mun, for several reasons.

[capi3101]

General cheekiness aside (the forum won't let you call him a smart-[KILLER RABBIT OF CAERBANNOG]), Simes has a point. What kind of engine do you have on that lander?

General rules are 7200 delta-V total for a Mun landing mission and about 6800 for Minmus. Those are minimal values and they both include the ~4500 or so you need to get into Kerbin orbit. A lander with at least 2700 m/s of delta-V should be able to make it to either destination, land and return.

Your craft description is inadequate for me to make a 100% accurate assessment. I'm assuming "some batteries and panels" is two Z-100s and 2 OX-STATS. I'll also assume a quad of LT-1 Lander Legs is part of the design. I figure if you're using a 48-7S engine you should have 3332 m/s of delta-V; with an LV-909 you've got 4321 m/s. Munar surface TWR with the 48-7S should be around 5.7, and with the LV-909 it should be 8.47. So you should be okay either way, though I would certainly consider adding a chute and a decoupler in there somewhere for when the whole thing has to come back home...neither of which will affect the capabilities of the craft all that much (3090 m/s of delta-V with the 48-7S).

So, I'm assuming the "landing failed" because of how the craft was piloted. If you're a beginner, a Mun landing is one of the early milestones and it takes practice practice practice. Folks here have given you good tutorials to follow, but basically you want to make sure you're going slow enough that when you hit the deck you're not exceeding the impact tolerance of the parts you're using (roughly 12 m/s, and ideally you don't want to be going much more than 5 m/s on impact if you don't want to risk parts breaking off). My advice - quicksave before you make the attempt (that way you can quickload and try again if need be), and make use of IVA; one of the gauges there is a radar altimeter, which will give you your true altitude above ground level. When it starts twitching, you'll have a rough estimate of the ground elevation (i.e. what your altimeter will say when you've reached the deck) and can use that to figure out when you need to be going slow. If you need more detailed instructions, holler.

If you use FennexFox's link to pull up an actual delta-V map, go with the second of the "images" on the top; to my knowledge it's the one that's most up to date.

Edited September 4, 2014 by capi3101

[jackboy900]

Thanks for the tips. For the engine I use is an LV-909 and tri-legs; The main problem is landing as when I got close I had to much speed and crashed

[Simes]

If you're going for a direct landing, rather than establishing an orbit first, slowing down enough to make a landing is much more difficult. If you establish orbit first, you bleed off a large amount of your velocity doing that, which means there's that much less to get rid of in order to safely touch down.

Beyond that, your lander ought to have enough spare dV that you don't need to burn right at the last minute in order to touch down safely; burning "too early" will waste some fuel but, as you've found, it's better to slow down too early than too late.

Edited September 4, 2014 by Simes

[EtherDragon]

Thanks for the tips. For the engine I use is an LV-909 and tri-legs; The main problem is landing as when I got close I had to much speed and crashed

Any way you could take a screen shot of your design and post it on Imgur, or something? =)

[capi3101]

Thanks for the tips. For the engine I use is an LV-909 and tri-legs; The main problem is landing as when I got close I had to much speed and crashed

Yeah, that happens. It does take practice to get it right; IIRC it took me eight or nine tries before I successfully stuck a Mun landing (not counting the ones where I arrived safely but tipped over on landing). Learning the IVA trick helped me out a lot in the early going (before I started using KER) and I still do it that way on those occasions where I go back and play the v0.18 demo.

[tsotha]

I found the easiest way to land is to go into a Mun orbit from your translation, then lower your orbit until it's completely circular at about 12km. This way you have just about the smallest amount of energy you can have before you actually start landing.

Then do a retrograde burn until your surface speed is zero and start going straight down.

I forget where I read it, but supposedly the rule of thumb is to try to keep your speed in m/sec at about 1/33 your altitude. Your true altitude, that is - use the altimeter in the cabin. Of course the most fuel-efficient thing to do is drop like a stone and then at the last minute flare out with maximum thrust such that your speed drops below 10 m/sec when the legs touch the ground. Of course, if you do that you're going to die about 99% of the time.

The other tip is when you actually set down make sure you kill the engine - if you land on a slope and leave the engine running it'll tip you over.

[SRV Ron]

Send a probe lander to Minmus. Leave RCS at home, it is not needed since you will use the Navball while steering your lander during descent to kill all drift. See photo below of an ideal Navball reading just before touchdown.

When you get good at that, try a probe on Mun. Yes, you can land something as simple as this with no legs on a slope.

Finally, go for a manned landing. Several design examples below. The drift here is acceptable at this near hover before touchdown.

The legs on this design were ejected on takeoff. And, there was more then enough fuel to get back to Kerbal.

Edited September 5, 2014 by SRV Ron

[TythosEternal]

Just so there's a direct link...

http://wiki.kerbalspaceprogram.com/w/images/7/73/KerbinDeltaVMap.png

Use this map in conjunction with a performance calculator, like Engineer or MechJeb, to design your ships to your mission requirements.

[jackboy900]

How do you post a screenshot

[Ruedii]

As a note, that map estimates on the high side for good reason. You want to play it safe.

Of course the best way to do repetitive landings on any Moon or small planet is to put a station in orbit with a 100% reusable lander. You can look at the chart on how much delta-V that saves. (Just send up tanks of fuel to fuel the lander.)

[capi3101]

How do you post a screenshot

The forums have been jacked up for quite some time now - the only way to post images is to use another site to host the image (if you don't have one of your own, an image-hosting site such as Imgur or Flickr works well; I use Imgur myself) and link to it with img tags ([ IMG ] put URL here [ / URL ], but take the spaces out of the brackets). Full Imgur albums have their own special tag ([ imgur ]) that you can just set the albums identifier between.

[Kerba Fett]

Here's a lander design I use that's similar to what you describe. If you place your landing legs on decouplers you can reduce the number of goo canisters to 2 and still have a balanced ship. These decouplers allow you to mount equipment inside of them to mix the 3 way symmetry of the legs with 2 way symmetry of everything else. They also widen the stance of the landing gear to make the ship less tippy.

Unlike SRV Ron, I don't eject them for the trip back. While you need to carry the weight of the landing gear back to kerbin they help keep the ship intact for maximum cash recovery.

You might also want to consider if you really want to take that science jr. Getting rid of it will gain you more delta V and make you less top heavy. Without a mobile lab to reset it the science jr can only be used once per mission and it's worth less science points than a surface sample.

This is the entire ship on liftoff. The lowest stage is 4 jet engines. If you rotate them 45' you can put 2 of them on a bicoupler. You can then mount 2 of these assemblies to a bicoupler. (a quad our tricoupler doesn't work. I've tried it) Mount as many intakes as you can on a liquid fuel tank and you've got a very fuel efficient lifter up to 20 km. It's also got a structural fuselage to mount the control fins and for the launch clamps to hold while the engines spool up.

Above that is the orbit/transfer stage. This uses the LV-T45 with an FL-T800 fuel tank. It's got 4 drop tanks of FL-T400's. 2 are just tanks while 2 have LV-909's and they're asparagus staged to drop the tanks without engines first.

The fuel lines in this image are actually wrong. They should run from the tanks with no engine to the tanks with the engines and from there to the main tank.

And above that is the lander in the upper image. It uses the LV-909 engine and FL-T400 and a mk1 pod with parachute.

With a good ascent this setup will get you into orbit around Minmus or the Mun before you need to decouple the transfer stage. This leaves plenty of fuel for landing and return to Kerbin. On Minmus you can do landings at multiple sites. For the Mun you probably want to just do 1 landing before return.

When you return to kerbin make your PE about 35km and you can areobrake to a landing without needing fuel to enter kerbin orbit.

[SRV Ron]

My ship in use has the far cheaper SRBs. The jets used are only economical if they can be recovered. Stock parts can be subbed for the KW ones on this career launcher.

A stock 23.5 version that did the same mission. However, it is quite tippy.

A variation that gives a bit more fuel for landing.

From the pre money days in Sandbox

Edited September 9, 2014 by SRV Ron

[jackboy900]

I want to say thanks for all the tips and I've manage multiple min us landings and are gearing up for the mun

[capi3101]

Glad to hear it. I'll caution you that Mun is trickier to land on than Minmus as a rule, largely due to two main things - higher surface gravity and hillier terrain. Procedure is still the same, you'll just need to keep a firmer hand on the helm while you're landing. F5 before your first attempt and F9 if (*when) you botch it.

Getting to Mun is easier than getting to Minmus, though. No inclination change, so aiming for it is way easier.

[Man in the Funny Hat]

I've used this for my initial lander. It's very simple and uses low-tech parts. No, it doesn't have gobs of science parts though you can stick goo cannisters on it easily. This is a lander meant for players who are finding it difficult to learn to land while early in career mode.

https://www.dropbox.com/s/7xg4om0iex3twzh/KSP%20Lander.png?dl=0

Other advice: Build a rocket that will get this lander into Mun orbit without needing to use fuel from the lander itself. I often use my next-to-last stage for the initial Mun de-orbit burn and then dump it.

Pick a FLAT landing site that is in daylight. Start by lowering your orbit altitude above the landing site to say, 10,000 to 15,000. That's keeps the duration of your final landing procedure low but still leaves time for you act. Make a save point to revert back to from this position, THEN start your final landing procedure.

Point retrograde and burn off all your orbital velocity. You'll start dropping straight down so now you just need to HAVE PATIENCE and keep your vertical velocity where it needs to be. Use IVA to check radar altitude - altitude in exterior view is given to "sea level" so note the difference.

Starting at about 5000m above ground keep your speed down to 50m/s. Starting at about 1000m above ground keep it to around 10m/s. Try to touchdown at LESS than 10m/s.

Use the save point to PRACTICE.