Duna Rockets

[Spaced Out]

Ok so i am planning a Duna trip but I have no clue what a typical rocket looks like for this. I am close to done with the tech tree but I just need to know what a typical duna rocket looks like.

Edit: It is a Duna and back mission with only three kerbals, and it is just for science. 

Edited June 16, 2017 by Spaced Out

[Cpt Kerbalkrunch]

I pretty much know what others are going to say, cuz I'm thinking the same thing; it can look like anything you want it to look like. The question is, what are your mission objectives? If you're that far on the tech tree there's almost nothing you can't do. So what is it you want to do? Is this a manned mission? If so, how many Kerbals are you bringing? Do you intend to drill? Are you gonna land on Ike while you're there (may as well)? Will it be a large lander that's returning to Kerbin, or an Apollo-style landing? There's an awful lot variables, so it's tough to give a good recommendation. And, sadly, I'm stuck at work. Otherwise, I'd throw a few examples of various types for you. Someone else will see this and throw some up, though.

For a quick and blind recommendation? Take your typical Minmus rocket. Make the lander a bit larger, with a couple of drogue chutes and a regular chute. Then make the rest of the rocket a bit bigger (or just tweak things) to compensate. You won't need a whole lot at Duna. And, of course, you'll learn a lot by just trying it.

Edited June 16, 2017 by Cpt Kerbalkrunch

[bewing]

Yup, build it so that it can go to Mun, land, and come back to LKO with no aerobraking. And that'll get you to Duna and back -- with aerobraking.

 

[Aegolius13]

18 minutes ago, bewing said:

Yup, build it so that it can go to Mun, land, and come back to LKO with no aerobraking. And that'll get you to Duna and back -- with aerobraking.

 

You might need a little more TWR to lift off of Duna,  relative to the Mun, since it has higher gravity and there is some (minimal) atmospheric drag.  But note that,  while Duna has an atmosphere, it's thin enough that "vacuum" engines line the Terrier and Poodle perform better than "atmospheric" engines like the Reliant or Thus.  Nukes are also quite viable,  though their height can be problematic for landers.   

My typical Duna lander is a reusible thing with an Mk 2 landing can, 1600 tank, Terrier, parachutes,  and the usual little stuff.   But many different approaches are viable.  If you're conning back to Kerbin, don't forget an engineer to repack your chutes!

Edited June 16, 2017 by Aegolius13
1600 tank. Not 3200.

[Spricigo]

As other pointed a buffed Mun rocket will be enough for Duna(or Ike). A bit more power to lift from surface and a bit more deltaV and you are good to go. 

An example craft,  for quite different mission parameters (plant a flag and sightseeing): 

 

[Foxster]

Some ideas...

Building a lander that can also make it back to Kerbin is easy and avoids all the docking nonsense.

A Terrier (or 2) is a good choice for lander engine. 

Air-brakes then drogues then main chutes will get you down with a minimum of fuel needed. 

Why take a crew of 3? One man is all you need to collect all the science. 

Dump the experiments and chutes on the surface before returning to save mass. 

 

[Cpt Kerbalkrunch]

And not to be pesky, but I would ask a couple follow-up questions. Are you bringing the extra Kerbals just to gain experience, or do they have a purpose? Are they tourists? If so, you probably won't need to bring them to the surface (unless it's part of the contract, which is doubtful at that stage of the game). Is one an engineer to repack chutes or run drills (or both) and the other a scientist to boost your science haul? Most would caution against the extra Kerbals (cuz they're smart), but I'm not one of them. I prefer large, multi-Kerbal ships. And I have an affinity for the MK1-2 command pod, though I'd recommend against it for your first trip. However, since this is your first trip to Duna, I'd consider it a missed opportunity if you didn't land on Ike as well. I'm trying to picture a lander (still stuck at work). I'm thinkin' a MK1 command pod with a passenger compartment for the other 2 Kerbals. Four 1.25m tanks radially around the central 1.25m tank. Apollo-style, you could easily land on Duna and Ike. The fuel tanks size and engines are up to you. Terriers are great, or Dart's for extra power. Both are low-slung and great for landers.

Actually, as light as that would be, 4 stacks of Oscar B's with Sparks would probably be the way to go.

Edited June 16, 2017 by Cpt Kerbalkrunch

[Foxster]

As you said you had most of the tech tree unlocked, here's a 3-man Duna return mission craft with loads of dV to spare...

Craft file: https://www.dropbox.com/s/ou4xycukh6su608/Duna 3 man 4.craft?dl=0

 

[Cpt Kerbalkrunch]

@Foxster I can see that's a good rocket, but my knowledge of Nerv's is nonexistent. With an Aerocapture at Duna, then the parachute landing, do you think he could make Ike as well? Or would that be pushing it?

Edited June 16, 2017 by Cpt Kerbalkrunch

[Foxster]

There's loads of dV to spare. Ike could be visited on the way to Duna or on the way back - even without aerocapture at Duna. 

[Cpt Kerbalkrunch]

Put this one together real quick as an example. A little short on time, so I didn't build a launcher. Sorry. However, I put it through some tests, and it lands on Duna and returns to Kerbin easily.

 

The 2 drogue chutes and single main chute allow it to land with only a small burst of thrust just before touchdown to slow down enough to keep from breaking a landing leg.

 

 

After leaving Duna's surface you can also land on Ike and get back to orbit. However, at that point you would need to re-dock with your transport ship to top off the tanks (hence the docking port on the bottom). It holds just under 800 units of fuel, and you don't even need half of that to get back home.

 

 

This is the ship in orbit of Ike after the 2 landings. You can see it's pretty much out of fuel. There's enough to rendezvous with your transport ship, but that's about it. If you're wondering about RCS, I would have it on the transport ship to save mass on the lander. And I never really use ladders except on worlds where it's necessary (Eve, Tylo, Laythe).

[Wanderfound]

If you've got Kerbal Engineer or similar to look at the ΔV values of your ship...

KSC to LKO requires about 3,500m/s. LKO to Duna landing under power requires about 3,000m/s, but you can replace up to half of that with aerobraking and parachutes. Getting back off Duna takes about 1,500m/s, returning to a Kerbin Intercept for aerobraking and landing needs about 750m/s. Build in a bit of slack to allow for piloting imperfections and you're all good. Be aware that Duna aerobraking needs to be done at scary low altitudes due to the thin atmosphere.