Landing with nuclear engine

[Itchylol]

I've been using the nuclear engine for some time, and the biggest problem is 80% of my landings end up with me falling over and breaking everything but the capsule. I can't reach with normal landing legs so I just attached a bunch of modular girder segments to be fixed landing legs. Still, even when spread out it tips over everywhere except on flat terrain. I really don't want to use any other engines to land since the nuclear engine is so efficient, and most planets/moons have low enough gravity the TWR doesn't matter. How do I land with the nuclear engine?

Edited May 24, 2014 by Itchylol

[Sirrobert]

There are a couple of things you can do.

First, the nuclear engine might be efficient, but it's also very heavy. So on dedicated landers, which only use their engines for landing, it might be worth more to save weight, than to save fuel. The transferstage (for interplanetery) should offcourse have nuclear engines, but for small landers, the added weight might even drive the deltaV up instead of down.

For landing on Mun sized things, the LV-909 is efficient enough, and also very light. The even smaller 48-7S is even better. Only .1 tons, compared to 2.25 from the Nuclear engine.

If you still want to use the nuclear engine, you can raise the engines by mounting them radially, instead of directly under the main tank. Mount them high, and than put the lander legs on the main tank. This way the engines are higher than the legs. However this does give you a relativly higher center of mass, coupled with a smaller landing base, which makes it easier to fall over if you haven't cancled out your horizontal speed.

Basicly: the NERVA is designed for interplanetery transfer stages, rather than for landing stages

[allmhuran]

More imaginative ship design will do it. Add landing legs to the girders, or build the ship so that the engine is not actually at the bottom, instead it is surrounded by its fuel tanks and the fuel tanks have landing legs. Or use more than one nuclear engine and mount them on small fuel tanks high up and radially, with fuel lines from the longer central tank.

Having said all that, uneven ground is always going to make landings tricky. SAS can help you, because even when you land it will try to keep you stable. Once your legs are deployed and your ship stops rocking you can turn it off.

[Red Iron Crown]

Alternately, you could mount two LV-Ns to the sides of your main tank so they don't hang down as far.

Edit: Oops, didn't see allmhuran suggested the same thing.

Edited May 24, 2014 by Red Iron Crown

[TeeGee]

Part clip the LV-N into the tank it feeds off of. Now you will have the room to place landing legs and the clearance for the engine bell.

[Laie]

More imaginative ship design will do it.

Exactly.

Shameless plug: http://forum.kerbalspaceprogram.com/threads/79215-A-convenient-career-mode-LabLander

This only really makes sense if you include a lab or have another reason why you want to make several landings in one trip. Otherwise, as sirrobert said: smaller engines offer a better deal for a single landing.

[Skorpychan]

Nuclear engines are GREAT for interplanetary burns. For landings, the combination of mass and lack of thrust makes them bad. The size is also bad.

Observe: http://imgur.com/gallery/uc1J8 - Nuclear-engined cruise stages, landers with small rocket engines.

[cantab]

I've used girders for landing legs when I was doing landings with very early parts. They work, but they're not ideal, being both heavy and not giving as good grip on touching down.

As much as anything else, technique is important. If you can land with minimum horizontal speed on flat ground, if you can react quickly and use the command pod/reaction wheel torque to keep the ship upright, you can land fairly top-heavy ships safely. Landing on your engines is perfectly possible if you're careful. If you can't do these things, well I managed to do this: https://flic.kr/p/nq5kAW

[KvickFlygarn87]

compared to 2.25 from the Nuclear engine

Actually, it's 2.5

[Red Iron Crown]

LV-N is 2.25 tons, Sirrobert is correct.

[technicalfool]

My old Gilly Rover from 0.19. Useless as a rover, as most rovers on Gilly are, however it shows how you can use a NERVA (or four NERVAs) in a lander.

[Tokay Gris]

This baby can land and lift off from Mun, Minimus, Ike, Bop, Pol, Val, Eeloo, Dres AND Moho. Not sure about Gilly, but should work.

Granted, liftoff from Moho is a pain and far from efficient, if fully fueled. But it does get to orbit.

Basic idea is to rendezvous on the ground with a kethane rover, fill up the tanks and then continue on through the kerbal system.

Here is Jeb during the test-drive to Mun.

Way to the top is quite long.

And to topic: All nuclear engines.

Edited May 25, 2014 by Tokay Gris

[Shna_na]

I often combat the problem of the part being too tall by attaching fuel tanks to the sides of the craft that droop a little low. I attach the landing legs to these.

EDIT: But keep in mind, the NERVA is not what you want to use for a landing stage. It might seem more efficient, but when you take weight into account it's most definitely not optimal for landing.

[merendel]

More imaginative ship design will do it. Add landing legs to the girders, or build the ship so that the engine is not actually at the bottom, instead it is surrounded by its fuel tanks and the fuel tanks have landing legs.

The problem I always have with this design is how to get it into space. once in space it works fine but if you need to put a launch stage under that central nerva it gets a fairing, when you decouple the previous stage that fairing blows the tanks on either side of it appart when it ejects. I've come up with a few ways to launch it without hooking to the nerva including launching that section upsidedown, launching 2 of them attached radialy to the lift rocket and even one system where I managed to attach a decoupler to the under side of one of the tanks so the lander was balanced over the the CoT and struted all over to keep it stable

[allmhuran]

Two solutions:

1) Rotate the nerva so its fairing eject pependicular to your two radial tanks

2) Use multiple-docking construction to attach the top section so the nerva doesn't get a fairing:

 _ p _ 
| |_| |
| |n| |
| |n| |
|_|n|_|
 d   d
 d   d  
|x|y|z|
  | |
 /   \
/     \
|     |

p = command pod
d = docking port
n = nerva
blocked lines = fuel tanks, etc

Construct the ship from the pod down to the two docking ports.

Attach single upward facing docking port (1x symmetry!) to either of the two downward facing ports

Connect a fuel tank below that (x in diagram)

Radially attach fuel tank y

Radially attach fuel tank z

Attach upward facing docking port to fuel tank z. This will NOT be connected to the above port in the VAB, but will dock with it immediately when physics kicks in on the launchpad.

Edited May 26, 2014 by allmhuran

[KvickFlygarn87]

LV-N is 2.25 tons, Sirrobert is correct.

Huh. Could have sworn it was 2.5! Sorry, Sirrobert!

[Sirrobert]

Huh. Could have sworn it was 2.5! Sorry, Sirrobert!

I took my numbers from the wiki, I've seen the wiki wrong before so it woulnd't have suprised me to be off a little

[SSSPutnik]

There are some nice LV-N landers for Tylo where the high Deltav requirement starts making them an attractive option despite the weight.

[cantab]

My recent solution to the LV-N fairing issues has been to avoid fitting decouplers below the LV-N. This also implies avoiding the use of a central LV-N. Not done a nuclear-engined lander, but here's a couple of transfer stage designs

https://flic.kr/p/nkQxru

Not the best picture I know. For the larger one, I've used a central 1.25 m stack, which includes some of my support equipment like the probe core, and the engines around that. For the smaller ones, I attached an XL girder to the bottom of the fuel tank, then used part clipping to add the 4-way adapter to the same bottom of the tank. Rotating the girder or adapter 45 degrees keeps the engines just clear of the girder.

Either way, the launcher then attaches below to the central element, and it all goes up with no troublesome fairings around the LV-Ns.

[Red Iron Crown]

Another alternative is TweakableEverything mod, which lets you disable fairings on decouplers.

The LV-N fairings are a headache, I wish they were just cylinders like all the others. Or detached with less force, at least.

[allmhuran]

My recent solution to the LV-N fairing issues has been to avoid fitting decouplers below the LV-N. This also implies avoiding the use of a central LV-N.

Not necessarily, here's an in game example (now that I'm home) of the construction I "blueprinted" earlier:

Edited May 26, 2014 by allmhuran

[ximrm]

@ OP:

I solved my problem with the short legs,by adding a servo-railing(from IR) just above the engines with the lander legs attached to them.

Worked fine for my rescue lander.

[GoatRider]

Here's another way to make a nuke lander

[TeeGee]

[Red Iron Crown]

Clipping does make it substantially easier.