a Duna return Vehicle

[Zaryulenko]

Hey, I need some help for my current project on Duna, but before anything ¡SAFETY FIRST! so i need to be able to return all the crew for this.

To be more descriptive im settling my first base for Khetane Extraction on duna, and I need an entry vehicle i could re-use during the crew transfers to ground from a orbital outpost

But here comes the problem: I have been there 3 times, every of them using TSTO (Two Stage To Orbit FYI) vehicles to perform the trip back home, but i just dont know what to do for a duna lander i could keep using for every crew rotation so i need tips to build one myself.

Thanks!

PS: I also need to know how to do spot-landings to land close to that base im gonna build, Im not really good when there's atmospheric conditions during descent.

Edited April 22, 2014 by Zaryulenko

[robopilot99]

From Duna's surface you only need about 3000dv to return to Kerbin. Its a good bit but its certainly doable. My advice is just to build big. A two stage lander would probably work well.

[Othuyeg]

My idea would be to make a refueling station in orbit and use a mixture of nuclear engines and a liquid fuel engine.

Edit: remember, once in orbit, you can repack parachutes during an EVA. You could utilize large parachutes to slow you down during landing.

Maybe use a liquid engine (skipper?) and multiple radially attached nuclear engines. Use the skipper to lift off the ground and the nuclear engines to meet up with the orbital station.

Edited April 20, 2014 by Othuyeg

[GoatRider]

Edit: remember, once in orbit, you can repack parachutes during an EVA. You could utilize large parachutes to slow you down during landing.

You can repack on the ground too. Last time I did it, the Kerbal wasn't even close to the chutes, just outside.

[Othuyeg]

You can repack on the ground too. Last time I did it, the Kerbal wasn't even close to the chutes, just outside.

Yes, that is true. I only wrote it that way because it felt more appropriate in the context of the conversation.

[Bagface145]

Be sure to use the nuclear engine. Although they do not have a lot of thrust, they have a high specific impulse so you don't need to worry (that much) about fuel!

[Zaryulenko]

Finally im back to see the replies but i think i wasn't clear enough...

Im planning to start a base on Duna surface, I got a space refinery at a 150x150km orbit around Duna and i need a lander capable of doing a round trip from station to surface and viceversa.

At the moment i got this on mind: "Build big or go home!" so maybe im gonna make a combined cycle lander (Whit high thrust during ascending start and the mighty BMNT Nuclear engine). and my main Design would be like a Space X Dragon.

thanks for the help guys

[cantab]

It shouldn't be too hard. The delta-V map quotes 1380 m/s for getting from Duna's surface up into low orbit. Getting down will need less since you can use aerobraking to help. If it's just for crew transfer that's well within the capability of a simple SSTO rocket. Engine, fuel, capsule, parachutes, landing legs, done. Add docking ports and RCS if you want to refuel without using the claw. You won't even need nuclear engines, and in fact I'm not sure how much the stock LV-N would help considering its own mass. If you're shipping Kethane up you'll need to scale up of course, but it still needn't be complicated.

[Zaryulenko]

I started to build it but i think Realchute doesn't let you repack all the times i want, so im going to test an drag-based passive slowing system built whit the B9 air brakes. Could it work well on duna?, its supposed to be a powered landing anyway

[Othuyeg]

A crazy thought: Make a space plane. Duna has enough atmosphere to allow for you to glide down if you have big enough wings.

[Pulstar]

Well, I know of two ways to make a SSTO Duna lander.

One is to use two or three LV-N's, they have enough thrust for Duna and their efficiency makes up for all the mass they add. To lift a three man capsule two are enough IIRC.

The other is to use those probe-sized 48-7s liquid fuel engine, four of them are more than enough to lift all the fuel you may need and a larger manned module like a 3-man pod, 2-man lander can or the hitchhiker. You need about 6 tons of fuel plus oxidizer, that's six fl-t200 tanks (or four fl-t200 and four fl-t100 tanks), should have plenty of fuel left after achieving LDO.

A crazy thought: Make a space plane. Duna has enough atmosphere to allow for you to glide down if you have big enough wings.

Depending on how where the kethane base he wants to ferry kerbals to and from is, this may be very difficult if not impossible. The higher the ground level the harder it becomes to land the plane safely due to lower atmospheric pressure, because you need to maintain higher velocity to glide down. You can counter this with enough wing surface area but that makes the second problem a lot worse, that being finding flat terrain suitable for landing. With large wings you are just begging for something to hit the ground and explode.

Probably the best idea would be to add some wings and control surfaces to make the targeted landing easier, but use parachute and drop slowly during the final phase.

[Zaryulenko]

A crazy thought: Make a space plane.

For crazy it sounds, I think its the best solution for my need for a Descent vehicle, It could also be much more precise as i could do a powered glide to my destination.

Too bad i can't test it well on Kerbin Atmosphere, so im gonna send my Prototype to Duna and see what happends. (Obviously Unmaned because Jebediah is on Duna Orbital outpost)

The Quetzatcoatl-D1 Is my actual Prototype, Whit an incredible Isp of 774.2 on Duna Surface!

Edit- Im happy to say that the best Spot i can exploit at the moment is Confirmed to be Flat enough to land a spaceplane!, I Scanned the planet whit a SAR array.

Edited April 20, 2014 by Zaryulenko

[Chronin]

I had a Duna lander that I just used, it worked pretty well. Four nuclear engines radially attached to it, an LV-45 in the center, 17 parachutes, 16 landing legs, and a ton of science stuff. It can also take two people, so if you want to take another person along, you can. I don't know that you'll use it or even like it, but whatever, here is the picture of it taking off from Duna

[Jouni]

I usually design my Duna landers to have around 2000 m/s of vacuum delta-v. With efficient engines, such as the LV-909, about 40% of lander mass should be fuel. Essentially this means that you need one FL-T100 for each 1.25 tonnes of lander mass (including the fuel tank). With less efficient engines, such as the Mark 55, around 50% of lander mass should be fuel, or one FL-T100 for each tonne of mass.

[KerrMü]

Hey,

for my Duna crewshuttle I used a combinatoin of a hitchhiker container, a Roxkomax X200-32 fueltank and 4 LVNs.

It has no Problem with returning, but the landing can be tricky, becaue the landing legs are too close to COM. But It works so well, that I´m testing a new version with 23.5 parts:

[sewerbird]

That's one sexy dropship

[Zaryulenko]

So i finally came up whit a good design of lander (Because the prototype rocket plane crashed)

And it was made "Apollo Style"

I like how its small and still be able to carry the amount of kerbals i wanted, too bad it will last only 10 crew transfers due to spare chutes from RealChutes but i could keep sending new landers to duna so it could be affordable

What do you guys think about it? Should i switch back to a taller lander using the engine of the Failed rocket plane? or i should keep this one and go ahead to start transferring crew?