Dunar Lander and Launch Profile Questions

[shoveycat]

Hey guys, ive been playing this game for around a year now, and ive taken kerbals to the hottest fires of Moho and the coldest pits of that Dirty Snowball in the Sky, however, ive never been able to return from any planet, i can take most moons fine, but the larger gravity and atmospheres usually trip me up, so i was wondering if anyone could give me an example of a Dunar Lander with return capabilities, so i know what to strive for, and also, your preferred launch style wouldn't hurt, either. Thanks!

[toomuchbrew]

You might want to do a command/interplanetary module and a second Lander module. Get into orbit, undock, land, science, take off and rendezvous/dock. That way you are not moving heavy loads. Maybe save that delta v for the return

[RawChicken]

Did this recently in career mode.

What I did was this:

I made a little lander with parachutes, science lab, command module, landing legs and little more. After testing the parachutes and the ascent stage of the vessel in Kerbin, I put the lander in LKO.

Then I did a interplanetary stage, which was a command pod with RCS, central fuel cans and 4 nuke engines attached radially. This way I can ditch empty fuel cans easily. I put this into LKO and dock with the lander.

Once refueled to its maximun, I go to duna.

Once in Duna, decouple the lander and land, pretty straight forward. Then, launch from Duna and dock back into the orbiting vessel.

This was the part I was afraid of, if the lander would be capable of getting into LDO.

Once docked and orbiting Duna, I saw I was empty of fuel. Had to take another vessel to Duna to refill the first vessel. Onced refilled just back to Kerbin and parachuted down the atmo.

Note: For the return, I ditched 2 of the 4 nuke engines to lighten up the vessel. Also, the lander looses its 4 radial tanks+engines and is left with only the central column.

Here is a picture of the lander.

Note on the lander: As I didnt have long legs nor stairs, I needed the command module to be near the ground. This was how it ended being! The 4 radial engines fire at the same time to start the ascent in Duna. Once empty, they are ditched and the vessel changes its orientation to burn with the engine mounted ontop. Just doing things teh Kerbal way!

Picture of the lander and the interplanetary stage. Also, the refueling vessel and a derping Jeb.

Hope it helped somehow!

Protip: always make sure of having a space docking part just in case you need to refuel in order to get back home!

Edited November 6, 2013 by RawChicken

[Franklin]

Take it in phases with support installations. A straight-up, single-ship pass from Kerbin launch to Duna landing and back is a lot more difficult than launching from Kerbin, docking with your LKO refueling station, transferring to Duna orbit, refueling again with your Duna refueling station, landing and taking the same route in reverse. Hell, make your ship modular and leave the transferring fuel tank with the Duna station and lighten your load that much more. Plenty of possibilities.

Support station/modular stuff gives you the freedom to land/launch on Duna with only the parts you absolutely need, with full tanks, and none of the heavy load you used to get from Kerbin launch to Duna orbit.

[capi3101]

Did a Duna trip Apollo-style for a challenge not too terribly long ago:

Javascript is disabled. View full album

Word of caution - use nukes instead of the four LV-909 quad. You can haul less fuel that way. And don't build your ship like I did - I built that transfer stage wrong (i.e. no docking ports).

I've also got this one for my current challenge, which has done very well on Mün but was originally designed for Duna:

By which I mean it's pulled all the stuff it has on Mün because it was designed to go to Duna; lemme try to be clear about that. With this design, the crew pulls a rendezvous in a separate crew capsule; the crew capsule contains the fuel for the return stage. You can see the intended transfer stage for that entire load (1700 m/s for about 80 tonnes overall) just below the lander.

For specific launch windows, check out http://alexmoon.github.io/ksp/

A good aerobraking altitude for Duna is 12,000 meters. Much lower than that and you're going in.

The atmosphere is thin; you can use chutes but you'll need so many of them that they become impractical. Plan on using a combination of chutes and thrusters.

For an idea of how many chutes, try http://ksp.freeiz.com/

Edited November 6, 2013 by capi3101

[vetrox]

You dont need much just a well designed craft. Asparagus staging helps.

Raw chicken has the right idea of an interplanetary stage and a lander stage. Although i launch mine together.

My duna craft (no science though) has a massivly over engineered lander which actually takes the descent stage back into orbit because of all the leftover fuel.

Im sorry i havent got round to sorting my imgur album but this is roughly what my career mode ship looks like. Pretty simple, only had skippers at this point in career.

Javascript is disabled. View full album

[Dispatcher]

A very basic Duna orbiter/ lander combo, but it does have some redundancies and fuel is a little more than required.

Edit: the lander engine is a single 909.

Edited November 6, 2013 by Dispatcher
More detail.

[shoveycat]

I feel its to late to make the correction, but when i said "Launch profile" I was referring to the Duna Ascent. Nonetheless, all great info!

[Dispatcher]

A Duna ascent should take about 1300 m/s delta V. My lander above gives me more than that, using a 909 and the smallest #2 diameter fuel tank. Of course everything depends on the craft design/ mass.

[capi3101]

The surface atmosphere on Duna is roughly the same as it is on Kerbin at 10,000 m, when most folks make their gravity turns. So in general, you're okay to begin your gravity turn as soon as you're maybe 1,000-2,000 m up at most (high enough so that you know you're not going to fly into terrain). Turn in the general direction of your return stage's orbit around Duna (or 090 if you're going for direct ascent). Shoot for no lower than 50k. 1,300 m/s; otherwise it's just like a launch from Kerbin.

[RawChicken]

I feel its to late to make the correction, but when i said "Launch profile" I was referring to the Duna Ascent. Nonetheless, all great info!

Look at my lander. Its not very powerful. You dont need nothing big. Just keep it simple and try to ditch as mas empty fuel cans as possible.

[borisperrons]

One thing i found to be useful to shed away weight, is to make your lander in such way that you can separate your chutes before launching from Duna. For example, I mounted them on the descent stage and on two detatchable radially mounted arms.

The fact that I was unable to detatch the radially mounted ones because of a design issue, is a totally marginal fact.

[700NitroXpress]

Here is my Gagarin Station with emergency escape pods and and crew transfer lander that goes to the surface and returns to the station. This station can go to Jool and return to Kerban, but this station is a permanent station for my Duna operations. The lander pod on the bottom is just a all around light weight design, but this station can tug my Eve lander after a mission to the surface of Eve or Moho.

Here is my Eve lander.

This is my interplanetary ship with a lander attached to it. The lander is capable of landing and getting back into orbit at Moho. This entire craft has been to Moho and back to Kerban with the new improvements. I remade the lifter to this model in the image, 200 ton capacity and it can be upgraded for heavier loads.

Edited November 7, 2013 by 700NitroXpress

[Mmmmyum]

Personally I did a Apollo style mission, and the lander had to be able to reach LKO from the launchpad (I like having a lot of extra delta-v)

[Ninja_Thomek]

I'm really not an expert, but did a purely chemical, non-aspargus science mission. In the end I had lots of dv to spare too!

Did take me a few tries though..

My first mission to Duna was an unmanned research and communications sattelite. It ended up in a polar orbit by accident, which is great for comms around half the year as it has nearly constant line of sight to Kerbin. .. It also carried 2 small communications sattelites orbiting duna. (using RT 2)

Duna II was a manned lander, but missed the encounter. I should get around to trying to get my kerbonaut back to kerbin some day.. He's been there for years!

Duna III reached Target, but I realized I put my new heavy duty landing legs upside down too late. It was supposed to be a robotic lander, but I also forgot to put a probe core in there.. At least it put up some communications sattelites around Duna.

Duna IV did some ****up in the encounter, by this time i was tired and just termitated it.

In the end Duna V made it with the same design as Duna IV:

Javascript is disabled. View full album

Edited November 8, 2013 by Ninja_Thomek