My First Trip to Duna

[Arctodus]

Hey all!

So, I'm planning my first trip to Duna I technically have a prototype ship in orbit around Kerbin ready to go, but I find myself doubting its capabilities, particularly the lander.

This is the lander - its well stocked for science (the primary goal of the trip), but I'm not sure it'll make it back to orbit from duna on 3x LV909s and a Poodle*. Do I need more firepower? Getting to orbit from Duna's surface is the primary goal - getting home is secondary, I have an orbital rescue mission standing by.

I was just wondering what everyone thought, and if there were any problems I may not have forseen?

Thanks in advance!

*Hell, I'm not even sure it'll survive the landing

Edited October 20, 2014 by Arctodus
Answered

[WillHop]

I'd suggest a lot more parachutes - Duna's atmosphere is very thin. As for firepower, it *looks* like you have enough to make it back in to orbit, but I would probably need to see the delta-v it has. Don't waste fuel on landing if you can help it as well, just in case!

[Arctodus]

It has seven chutes, but I'm sure I can fit a bunch more on there

I'm not sure about the delta-V, without a calculator I'm scuppered when it comes to maths, lol. Seat of pants is where its at? *manic, hopeful grin*

EDIT: Now comes with 13 chutes

Edited July 2, 2014 by Arctodus
MOAR CHUTES

[Pecan]

BIG lander! Leave the lab in orbit and ditch that huge RCS tank. If you aren't confident about docking it might take you 100 units of monopropellant, if you are it shouldn't take more than 10! Use the Kerbals on EVA to collect the science from the experiments and store it in command pod, then jettison all the mass of the used science instruments. Do you really need 3 Kerbals on the surface? The 2-man lander can, or even a 1-man one, is much lighter. If you can lose as much mass as possible you'll need less fuel, and so even less mass, and therefore less powerful engines will be able to lift it (get rid of the Poodle).

My preferred but still-bigger-than-it-should-be lander for Duna is in section 4 of the last campaign chapter here.

[Taki117]

If you have a dV calculator you only need about 1500m/s dV to get into orbit of Duna. then it's just a matter of rendezvous and docking.

[Arctodus]

Thanks for the help guys - a much smaller lander is currently winging its way to Duna as we speak It should be there soon, and hopefully all will be well.

......I have rescue standing by

[NecroBones]

You'll probably need a powered landing (at least in the last 100 meters) even with loads of parachutes. Remember, Duna's atmosphere is only about 20% the density of Kerbin's at the surface (at least that's easier than Mars, where it's only 1% of Earth's). The gravity is weaker, yes, but you still need a lot more parachutes than you'd need on Kerbin for a parachute-only landing.

The surface gravity is only about 30% of Kerbin's though, so weaker engines are OK, as long as you have enough. With a poodle and three 909s, you have about 370 thrust. With that heavy of a lander, I'm not sure. I'd have to see what the mass looks like. If you replaced the 909s with LV-T30s or LV-T45s, you'd probably have more than enough. But a smaller lander would be even better.

[Eric S]

You'll probably need a powered landing (at least in the last 100 meters) even with loads of parachutes.

My rule of thumb for non-powered landings on Duna is one radial parachute per ton of craft, and that's assuming that the craft isn't particularly fragile. It's generally easier to do a power assisted landing, the fuel will weigh less than the extra parachutes.

[Warbird]

Toss Kerbal Engineer on there so we can tell what we're working with if you can. That lander's pretty beefy, so it's hard to say what the capabilities are by looking at it. I would highly recommend an Apollo style lander so you can keep things light. Plus, once you finish with the lander, leave it behind and it's that much less mass to carry back home.

[Random Tank]

Just a tip: divide each engines thrust by 10 and that how many tons it can lift (including itself); divide the craft's weight by 3 and that's about how much it weighs on Duna... Also it's about 1380m/s of dV to orbit from Duna, and you can have a lovely high TWR as the atmosphere is 5x thinner than Kerbins... Duna is a breeze!

(If you didn't know how much the craft weighs, launch the craft, go in map view and then click on the 'I' on the right side; it will tell you there!)

[Zylark]

Looks mighty big - too big. Which means you'll need plenty of chutes to make a safe landing, and quite possibly some more powerful engines for getting off the orange rock again.

Here's my recent little Duna Lander:

And here it is by the mothership delivering a used science-pod and about to pick up a fresh one:

As you can see it is a pretty lightweight design. Gets down there pretty safe using plenty of radial chutes and virtually no burning of rockets apart from the initial de-orbit and a small burn to soften the landing a bit. Getting back up it got roughly 200dV to go after circularizing in a 75km orbit.

[Arctodus]

Thanks for the help everyone

I switched out the Poodle for a Skipper for a little extra 'oomph', made a power-assisted landing this afternoon Had 18 chutes slowing me down, though I think I may have damaged one or two landing legs, but I should be fine I have enough fuel to get to orbit, but not home - SO! I sent the rescue ship anyway to dock and bring my brave lads home!