Help with Duna design please- will owe multiple beers

[zeul1337]

Greetings. I'm fairly new to KSP and besides that, I am a "purist" meaning I don't want to install any mod whatsoever.

Having said that, I am looking for anyone with enough patience to help me design a decent Duna ship. I have tried every design that I could think of, mainly I failed to lift off Kerbin and if not, ran out of fuel on return/deep space.

So far I have designed all the ships myself (for Minmus, Mun) and have had a bit of success. What I'm looking for is someone to share with me a proper interplanetary (Duna) ship design that corresponds to my tech tree. I would like to use that model and adapt it in the future for other interplanetary expeditions (mainly the early ones until I get a grip on the process). If this could be done with a saved ship file, that would be totally awesome. There are no limits to what I can learn from inspecting such a design up close.

- no mods

- v0.23

- 3-5 science juniors + goo canisters

- a bit of spare fuel to leave room for orbit errors

- min 1 kerbal

I know most of you will be compelled to send me to complex articles and guides but mainly I'm just looking for pointers on basic interplanetary manned rocket design that I can adapt/copy to suit my needs. So if anyone would be kind enough to help me with a basic proper ship save file (and if you want - a few pointers) I would forever appreciate it and it would change my KSP experience forever.

Thank you in advance.

John

[bsalis]

Possibly best to look in the Spacecraft Exchange for examples. Although you may not have the parts for them, they may give you ideas.

As for planning an interplanetary. Get a hold of a delta-V map, and work on your stages backward. So build something that can get to Duna orbit and return to Kerbin. Then build up to something that can get from LKO to Duna low orbit. Then build up for launch pad to LKO.

As for knowing how much delta-V a stage has well.... you can guess it, calculate it by hand, or just use a mod.

[Luis]

I'd also add that what you are proposing is a fairly big jump from your previous missions. The last time I sent a manned mission to Duna (which was .20 I think, I've been resetting my saves each version since career mode came out) it involved multiple launches to LKO, assembled and refuelled in orbit. In my current save, I haven't unlocked mailsails yet, have I left Kerbin's system. I'm planning to go to Duna next, but it will be an unmanned lander to do some atmospheric and surface science first. Depending on how that goes, I *might* attempt a manned mission.

I realise this isn't really answering your question. I'm just saying you shouldn't feel bad if you can't put a Kerbal on Duna as the next mission after Mun. It's really hard.

[Jouni]

Duna landing is mostly a glorified Mun landing, with a lot of waiting. You need less fuel to get there, but more fuel to get back. Interplanetary transfers are more complicated than going to Mun, and aerobraking is prone to failure, which probably explains why going to Duna feels such a big step forward. Some people also delay sending manned missions there, because sending just one kerbal on a long mission feels wrong.

The hardest thing in the OP's proposed mission is the number of Science Juniors required. Without that requirement, something as simple as this could get the job done. While Science Juniors are pretty lightweight, they are also quite big, making lander design challenging. As an added bonus, their connections have a tendency to fail when parachutes open.

[Silverchain]

Can you say what tech you have unlocked, please?

[Mako]

I have a manned Duna ship from right after my Minmus and Mun missions. I'll take a screenshot or two and post a craft file in an hour or so. I'll try to catalog the parts if I can so you can see if you have the tech unlocked. I don't think it hass all the science you're looking for on it, but I minimized it because Duna doesn't have biomes yet. All science can be returned to Kerbin for maximum gains.

[John FX]

This is my Duna mid career craft. Not sure how well it matches your tech tree but here it is. Not sure what it is capable of either but it will at least do a flyby.

http://www./view/trdu1fu3j3tsfma/Duna_mid_career2.craft

[Dave Kerbin]

If you take a screenshot of your current tech tree I could offer some suggestions or designs.

From your description it sounds like your first issue is really about the booster to get into orbit, it may be that you are trying to build too big a ship.

One thing that will differ between a Mun mission and a Duna mission is that you will probably land mostly on parachutes. However Duna has a very thin atmosphere. You'll need more parachutes and you'll need to make sure everything is secure otherwise the sudden stop when they open will tear the ship apart.

[radonek]

If you are serious about avoiding mods, your biggest problem would be delta-v calculation. You can do a dress rehearsal on Mun: Lift you lander up, then let it do KOI-Mun-landing-Kerbin trip on its own. That's about 1600m/s delta-v, You need 1400 to get off Duna and have a bit on the side for soft landing. Once you are sure your lander can hadle it's job, you are set. You can take wrong turn elsewhere, but that can be helped with automatic tankers. It's not exactly bad idea to send one upfront, just to be one the safe side. If this is your first interplanetary transfer, a bit of practice can't hurt. (I speak from experience…)

[Rusty6899]

If you don't want to use MechJeb for delta-V calculations (an admirable choice) you really could do with learning how to calculate delta-V yourself, as it will enable you to design a much more efficient craft.

The best advice I can give you is to pick the most fuel efficient liquidfuel engine for your interplanetary stage. If you have the LV-909, then that would probably be ok with about 2 tonnes of fuel to take a lander/science module to Duna (assuming that everything excluding the engine and fuel tank weigh about 2 tonnes) if it is more, you need more fuel.

To get that into the atmosphere, asparagus staging is your friend.

[Mako]

Here's my Duna craft. It isn't pretty but it'll put a Kerbal on the surface of Duna and bring him home with a bunch of science. It has 3 Goo Canisters, one Science Jr., one Thermometer, and one Barometer. All science comes home; no need for transmission (other than crew reports which gives full value for transmission). When I did my mission I decided not to get any science from around the sun and only do science within Duna's influence. I did not attempt any interaction with Ike. It got me enough science that my next mission was a Jool and Jool's moons flyby (I botched that with overzealous timewarp but still managed to make it home with over 3000 science).

It requires the following tech nodes (from left to right and top to bottom):

Start

Basic Rocketry

General Rocketry

Stability

Survivability

Advanced Rocketry

General Construction

Flight Control

Science Tech

Heavy Rocketry

Fuel Systems

Advanced Construction

Advanced Flight Control

Electrics

Space Exploration (only for Thermometer)

Heavier Rocketry

Advanced Exploration

Abort Action Group is set to save your brave Kerbals (Leave thrust at Full and clear the rest of the ship, then cut throttle and press 1 for Landing)

Action Group 1 is Landing Mode (Lowers Landing Gear, Turns on Lights, Deploys Chutes)

Remember to repack Chutes for Landing at Kerbin and it should have ample fuel for less than perfect flying.

https://www.dropbox.com/s/w2e73auu3ffpy4g/Duna%20Lander%20Mk1.craft

Please let me know if it works for you or if you have any issues. If you're missing certain tech nodes to use the craft I can attempt to edit it and reupload.

Edit: I just totaled up the science received from this mission. I was able to get 16 different science reports and bring home a total of 1246 science points. I also wanted to add that this was the first time I'd been to Duna in a vehicle of my own design and only the second time I've been to Duna.

Edited February 18, 2014 by Mako

[capi3101]

I need to know your level of tech before I can offer any kind of solid advice, especially if you're looking for a specific design. Otherwise all I can offer is design suggestions.

[Xiphos]

Here's how I made my first duna return craft. First I built a craft that can lift off kerbin and make low kerbin orbit. (Since I knew duna was similar to kerbin, but didn't have as dense of an atmosphere, I knew(hoped) I would have fuel left over for the transfer burn back to kerbin) This craft should have small fuel tanks and small engines, use asparagus staging, and have a one man capsule. If you create a craft that can do that, you will have plenty of fuel to take off from duna and return to kerbin. That is your landing and return stage. Second, you must build your transfer stage. This stage can be smaller than expected, maybe 4 small engines and a medium tank. Thirdly, you must build a lift-off stage to get the entire thing into LKO. This will require some experimentation, but I'm sure you'll get it.

Also, you should know how to aerobrake when you arrive at duna and use F5 to quicksave to get the perfect maneuver. Even when you enter the landing sequence of your mission, it's easy to hit the wrong parachute or the structure of your craft could fail, etc, so use F5 and F9 to reload.

Another trick I learned is when you first enter the SOI of another planet, put a node down and drag the blue circle so your Pe drops to the desired altitude above the planet. At this point in time, it should cost you VERY little Dv to do this. Your Pe now should be at your desired aerobraking altitude.

Edited February 18, 2014 by Xiphos

[Sabreur]

If you have access to docking modules, I strongly recommend designing and launching two craft - one for the actual Duna landing, and the other as an interplanetary module to get the lander to Duna and back. This makes it much easier to get everything into orbit and still have fuel. It also means that if you miscalculate and are low on fuel after launching, you can send up a fuel-bearing probe to dock with your spacecraft and top off the tanks. It's also very handy for the Duna landing itself, since you're not forced to drop tons of fuel into Duna's gravity well only to lift it back out when you leave.

The interplanetary module will have the highest-ISP engines you can manage - nuclear engines if you have them. If not, just grab whatever engines have the highest ISP value. The basic design is a ring of engines around a big fuel tank. You don't need much thrust for this module, but don't skimp too much on engine power or your maneuvers will take ages to complete - that hurts efficiency, but mostly it's just a drain on your patience. I usually go with 4 nuclear engines, although that's probably overkill. Two is the minimum I'm willing to use, although you can probably get away with a single nuclear engine if you've got enough patience.

The lander module will have a bunch of parachutes - probably twice what you need for landing on Kerbin - and some high-efficiency engines. Duna's atmosphere is thin, but aerobraking is still the most efficient way to land there. Make sure you enter Duna at a very shallow angle to maximize the amount of time spent aerobraking. Even with parachutes, you might need a little bit of engine power to keep the landing soft, but if you've done it right you'll land with 99% of your fuel remaining. One upshot of the thin atmosphere is that engines which are most effective in vacuum are still decent on Duna. Nuclear engines are a bit heavy and awkward for a lander, but the other high-ISP engines work fine. Duna's gravity is low enough that you don't need much thrust to make it back up out of the atmosphere. If you're having trouble getting back into orbit, make your lander such that the science modules can be detached and abandoned on the surface of Duna - you can have your Kerbal get out and physically move the science into the crew module for return to Kerbin so you don't have to haul the weight of the science modules everywhere.

One thing that helps a lot is to make your Duna transfer a the right time - a quick search for "Kerbal Interplanetary Transfer" should show you some good guides for how to get that done so that your delta-V requirements are as low as possible. Just don't get too obsessed with transferring at exactly the right time - an error of a few days will cost you some delta-V, but Duna is big enough that you don't have to be super-precise with your intercept.

If you don't have docking modules yet, your job gets harder - but not impossible. Instead of having separate spacecraft, you'll use separate stages. Just make sure that both the lander and the interplanetary stage have crew capacity. Use the lander stage to land on Duna and get your science, then rendezvous with the interplanetary stage. EVA to move your kerbal to the interplanetary stage (don't forget to take your science with you!), then abandon your lander stage in Duna orbit and return home. The main disadvantages of this method are that you have to launch everything in one piece and you don't have the option of refueling once you are in orbit.

[Oggula]

Here is my early tech Duna and Ike double lander. Quite simple to control and figure out, but can be tough to handle on the low ascent. Has 3 Science jr, 3 mystery goo, and 3 thermometers. Its designed to land on Ike too in one launch so there should be plenty of fuel if you aerobrake, even if you do a partially powered descent. Also, its much simpler than any I've seen on here so please choose it, it really kicks ass

https://www.dropbox.com/s/jpcg46nj99k066e/Tech%205%20Duna%20Lander.craft

[zeul1337]

yeah sorry, I forgot about the screenshot when I made the thread. Here is the current tech tree and I have a spare of 1799 science. Please do suggest what advancements to get in order to facilitate my trip to Duna. I'm guessing Advanced Science Tech is a no brainer?

[Skorpychan]

LKO-Duna and back: http://imgur.com/a/uc1J8#3

Duna-Duna orbit, and LKO-Kerbin: http://imgur.com/a/uc1J8#0

The lander needs a redesign due to the transmission nerf in .23, however. And I use KER and MechJeb for avionics and rendezvous/docking, respectively, so not 100% stock.

And the space tug may need auxiliary fuel tanks, but those are just Rockomax X32 tanks with Sr docking ports, RCS, and a set of little radial engines.

[capi3101]

You've got the Science; absolutely I'd grab Advanced Sci Tech if I were you. I'd have to compare your tree a bit more to the full tree to make other science suggestions. You've definitely got enough tech for an interplanetary flight, no doubt.

I'd next get Specialized Construction so you've got at least basic Clamp-O-Trons and then follow it up with Advanced MetalWorks. Only another 480 science. That'd open up a possible lander - transfer stage combination. You could build a transfer stage pretty damned easily - like this:

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Actually, you don't even need the BZ-52s to do a design like this; you could do it with the Modular Girder Segments, which are Starting Tech. They allow fuel cross feed and are still reasonably sturdy. You'd just set them down parallel to the edge of the central tank. Only drawback is that they look ugly.

In your case, you'd replace the large probe core with an OKTO probe core and the Clamp-O-Tron Sr. with a standard Clamp-O-Tron. I'd recommend sticking the panels and batts to the sides instead of the tops like you have them. That's only 42 tonnes - easily launched with the tech you've got. You could even launch it single stage - your booster would consist of a stack decoupler and seven stacks, one centerline and six outboard. Each individual stack would consist of -

5x X200-32 Fuel Tanks

1x X200-16 Fuel tank

1x LV-T45 (center)

6x LV-T30 (outboard, on BZ-52s just like that transfer stage design)

Plus enough struts to keep the whole thing from pancaking. No fuel lines - this ain't asparagus...which you could do and it'd be way more efficient than the single stack to boot. If you need to see what the actual design looks like, holler; I haven't got this actual design built but it'd be pretty easy to do.

That oughta get you a transfer stage into orbit with enough juice to haul a lander with a mass of up to 58 tonnes to Duna and back with a big enough margin for error to cover everything except for extremely poor piloting (for the record, the round trip bit under optimal conditions requires 1,710 m/s of delta-V and the 58 tonne figure would give you 150% of that). I don't have any RCS anywhere on that transfer stage so she won't turn very fast unless the engines are lit; that should only be a consideration when it comes time to dock.

Which just leaves you to design a lander with the specifications you want. It'd need about 1500 m/s of delta-V all told, more (2600 at least) if you don't add chutes.

Edited February 18, 2014 by capi3101

[Taki117]

Why not take the Science Lab with you on your trip? Sure It's big and bulky, but you can clean the goo and science experiments so you are only lugging around one of each (Probably on your lander) saving you about as much weight.

[Wayfare]

My first interplanetary craft was this beauty, video courtesy of HOCgaming:

A bunch of the parts no longer look quite the same but it shouldn't be too hard to piece together. It's simple, rugged, has tons of fuel and the four nukes provide enough thrust to lift it off most solid bodies except Eve, Tylo and Kerbin.

You can put large parachutes on top of the engine nacelles to help with landing on Duna. You should be able to make it there and back without the slanted drop tanks so you can leave those off. The trick is getting it to orbit with most of its fuel untouched. If you have trouble lifting it, consider picking up our Munshine lifters (we recycled the name) which include low-tech Career Mode versions. Hope this helps, even if just for ideas!