Duna lander

[Cannon]

Although i've done it 100 times in older versions i feel like my old lander won't work as good as before.

I want to land 3 kerbals, Jeb, Bill and Bob.

This is how my old lander looked like:

will this be enough or should i change something?

Edited August 6, 2015 by Cannon

[Kaos]

In case you have not done it, you should remove the oxygen from your tanks, as the nuclear engines do not use it anymore. And the engines are heavier.

I do not know, if that will still works, but it might be very well the case. There is nothing that can tell this more than an experiment.

[Cannon]

In case you have not done it, you should remove the oxygen from your tanks, as the nuclear engines do not use it anymore. And the engines are heavier.

I do not know, if that will still works, but it might be very well the case. There is nothing that can tell this more than an experiment.

yeah i removed the oxygen, i guess i'll try it out

[Xannari Ferrows]

The plane parts can help with your Delta-V, as their structural mass is lower than rocket fuel tanks.

[CalculusWarrior]

The amount of nuclear engines you have there isn't the best. Engine thrust scales with atmospheric density now, and while Duna's atmosphere is less dense than Kerbin's, you're going to be reducing the engines' already-paltry thrust. Try going for a single 2.5 metre capsule and engine, perhaps a Skipper or Poodle? Heck, even aerospikes, due to that they maintain the same ISP regardless of atmosphere. All those nukes are just increasing your ship's mass far more than it needs to be, and you need bigger rockets to get it to Duna in the first place.

Bear in mind that this is just my personal preference, and if you like the nukes, feel free to keep them. Try installing Kerbal Engineer to see how much thrust you get at Duna 'sea level' to determine if the ship is still viable.

[Tatonf]

Hello,

If you're open to critics, can I suggest you to re-design tour rocket ?

The main problem is that each atomic motor weighs 3 tons and you're wasting a lot of delta-V with them. Plus, due to the fact that atomic motors only consume Liquid fuel, the conventional rocket tanks have terrible dry mass due to the unused oxidizer space. You should consider using plane parts.

I checked your rocket with KER and this is what I get :

You can actually get a better amount of Delta-V with this :

Ok it's not perfect for landing. Can I suggest my own Duna lander here ? It have enough fuel to get back to Kerbin.

Ho and you don't need to spam that much reaction wheels !

[Mastikator]

Just go with a poodle? It has 8 times higher TWR in all situations.

Or use the liquid fuel only tanks, they contain 400 liquid fuel instead of 180/220.

[Sharpy]

You should replace the tanks with pairs of LF fuselages. The oxidizer leaves you with 45% of the fuel you used to have - for each 0.9 unit of LF and 1.1 unit of Ox nukes used to burn, now they burn 2 units of LF.

Although if it's meant *only* as a lander, even single LF fuselages should suffice. One jet + one nuke + one LF fuselage plus bare minimum plane parts can lift itself into LKO. 7 nukes should have no problem lifting three pods plus some stuff into Duna orbit.

[Cannon]

Hello,

If you're open to critics, can I suggest you to re-design tour rocket ?

The main problem is that each atomic motor weighs 3 tons and you're wasting a lot of delta-V with them. Plus, due to the fact that atomic motors only consume Liquid fuel, the conventional rocket tanks have terrible dry mass due to the unused oxidizer space. You should consider using plane parts.

I checked your rocket with KER and this is what I get :

http://image.noelshack.com/fichiers/2015/32/1438728741-2015-08-05-00002.jpg

You can actually get a better amount of Delta-V with this :

http://image.noelshack.com/fichiers/2015/32/1438728749-2015-08-05-00003.jpg

Ok it's not perfect for landing. Can I suggest my own Duna lander here ? It have enough fuel to get back to Kerbin.

http://image.noelshack.com/fichiers/2015/32/1438728749-2015-08-05-00004.jpg

Ho and you don't need to spam that much reaction wheels !

Gonna try that design, i like how it looks

[Cannon]

What kind of lifter are you using, this is what i came up with, hope it's gonna be enough

[GeneralVeers]

will this be enough or should i change something?

Uhhhh.....you've got some overbuilding there.

I like it.

You've got a lot more hardware than you need, but that should do it; two nuclear engines and 720 fuel will get you on Duna (in ONE piece) and back into orbit (also in ONE piece). And you've got 720 per pair of nukes on that lander. (The nuclear engines' loss of ISP in Duna's thin atmosphere won't be a problem)

What you want is parachutes. I can't see for sure, but it looks like you don't have any. Throw on some radial chutes. You'll still need the engines to make a soft landing, but the chutes will save you a chunk of fuel on the way down. Then your crew can repack the chutes after you land.

[Tatonf]

It's part of a rocket that I intended as demonstration for beginners, but I gave up on it. You can download the .craft here.

You are supposed to begin the gravity turn around 400m. You just need to hold "D" and the very low amount of torque should prevent you from overdoing it.

But once you decouple the SRB you have the classic issue you get with long and thin rockets : they wubble like hell. You have to deactivate the SAS and pilot it yourself (you can also reduce the gimbal). But I found it to have good tolerance with the usual "fliping rocket problem" that happen when you're not ligned up with your prograde vector.

The ascending stage is supposed to put yourself in LKO. After that, decouple. You have then the transfering stage.

The ship is designed to be aerocaptured by Duna. Before entering it's atmosphere, decouple, and you have a heat shield. I don't think it's really necessary but, well, you never know what can happen with future updates. They could make aerobreaking even worse than it's already is.

Then decouple and you have the final stage I already showed you. You have two drogue chutes then three classic chutes. A retroburn before touch down is required.

After that the rocket can go home. Deouple before entering Kerbin's atmosphere and you have a new heat shield. Don't forget to repack the chutes !

And here you go. Each stage have extra fuel so you can make some mistakes, but nothing too extreme.

Edited August 5, 2015 by Tatonf

[Phil deCube]

This is my Duna lander. It goes to Duna and back for a Kerbin landing, but with just one Kerbal. It shouldn't need much souping up to get it to deliver three.

[juanml82]

This is my Duna lander. It goes to Duna and back for a Kerbin landing, but with just one Kerbal. It shouldn't need much souping up to get it to deliver three.

http://i.imgur.com/1fKJwBA.jpg

I don't know, but I'd think about replacing the outer ring of terriers with aerospikes. You double the weight, but they have more thrust, specially in the atmosphere - then again, Duna barely has an atmosphere.

[jwenting]

a few ideas...

[Cannon]

I've landed but can't get back to kerbin :/

This is what i have left after landing:

And btw i'm near the south pole:

I can't get back to Kerbin, i mean i can escape Duna's sphere of influece and get an encounter with Kerbin but after that there is not enough fuel to slow me down and land at kerbin, what should i do?

[juanml82]

You can aerocapture at Kerbin, although I don't know how risky it would be returning from Duna. If you have enough fuel for some small course correction, you may try entering Kerbin' SOI in a curved fashion, instead of zooming in and out in a straight line, so your Kerbin periapsis catches the Mun from behind (kind of "embracing" it) - then the Mun will change your trajectory towards Kerbin and you'll be captured without an aerocapture.

[Cannon]

You can aerocapture at Kerbin, although I don't know how risky it would be returning from Duna. If you have enough fuel for some small course correction, you may try entering Kerbin' SOI in a curved fashion, instead of zooming in and out in a straight line, so your Kerbin periapsis catches the Mun from behind (kind of "embracing" it) - then the Mun will change your trajectory towards Kerbin and you'll be captured without an aerocapture.

good idea, i'll try that

[ajburges]

You can aerocapture at Kerbin, although I don't know how risky it would be returning from Duna. If you have enough fuel for some small course correction, you may try entering Kerbin' SOI in a curved fashion, instead of zooming in and out in a straight line, so your Kerbin periapsis catches the Mun from behind (kind of "embracing" it) - then the Mun will change your trajectory towards Kerbin and you'll be captured without an aerocapture.

If you follow optimal transfer, it's not much worse than Minmus return. Hint: aerobrake velocity is approximately ejection velocity (without braking manuvers).

By the same token, Duna aerocapture is also pretty safe.

[Cannon]

Returned finally ^^

[Tatonf]

Well, other people have already responded, but yes this craft is designed to be aerocaptured by Kerbin and without any tricks involving the Mun. You can set a peripasis of 25 000m and land safely, as long as the heatshield is ocrrectly oriented.

Edited August 6, 2015 by Tatonf