Mini duna lander!

[tippy12345]

Whats the smallest duna lander you can build that can land from orbit and get into back into duna orbit again? plz send photos

[Alshain]

This seems like a challenge.

[Phil deCube]

This got me back into orbit, to Kerbin, and back on Kerrafirma. Does that count?

Edited July 15, 2015 by Phil deCube

[Foxster]

Here's my 7t craft that will do this with plenty of dV to spare...

Of course, unmanned could be made much smaller.

Edited July 15, 2015 by Foxster

[Nich]

Phil 4 terriers seems like overkill and your fuel looks a little low to make it back to Kirbin but if you did I am quite impressed. I am assuming this was before 1.0.4 aero?

nm I missed the 3 detaching that is an impressively optimized craft

[Tatonf]

I can't think of anything smaller :

This 565 kg craft features :

- The probodobodyne OKTO2 for control

- A Z-200 battery plus 2 photovoltaic pannels for electricity. You could get rid of the battery and one of the panel, but it lets you with only 5 electricity units. While possible it's too annoying.

- An Oscar tank and two spiders for thrust

- A Small reaction wheel. Even if the spiders are supposed to have great thrust vectoring (8° !) the spacecraft was totally uncontrolable without it. I don't know why.

- A normal chute and a drogue chute for landing. The drogue chute is decoupled during landing, which allow a 300 m/s boost in delta-V.

Here are some pictures I made :

Note that the chute isn't enough for slowing the spacecraft, you have to use some retrorockets.

I picked a random landing site (only condition was on the day side), but I think it could go ASL. While il would consume a bit more fuel to go back in orbit, the parachute would be more effective, so it doesn't change anything I think.

Edited July 15, 2015 by Tatonf

[Foxster]

I feel that's a tad over-engineered ...

(That's an Ant engine clipped up a little bit.)

Edited July 15, 2015 by Foxster

[Tatonf]

I have troubles landing without a drogue chute, but I guess it's possible at low altitudes.

I considered the ant engine but though the TWR would to be to week.

[Foxster]

I just tried it without a 'chute at all...

The mass saving is nice but all of the dV gained from that and a bit more is needed to land. Only left 1500 or so to make orbit. By luck I landed at a spot a bit over 4km high, so managed to scrape into orbit. It took 5 attempts though (thank goodness for F5/F9!), so I'm not sure I'd recommend this as an ideal solution.

Edited July 15, 2015 by Foxster

[Tatonf]

Well in a challenge way that's ok I think, since it makes your spacecraft smaller.

For a more practical solution you could do the same thing that I've done : decouple your parachute.

EDIT : I know remember why I choose the spider : their gimbal were supposed to maintain the stability of the craft without a reaction wheel.

Edited July 15, 2015 by Tatonf

[Phil deCube]

Phil 4 terriers seems like overkill and your fuel looks a little low to make it back to Kirbin but if you did I am quite impressed. I am assuming this was before 1.0.4 aero?

nm I missed the 3 detaching that is an impressively optimized craft

Hi Nich, Yeah I do think it was before 1.0.4. Probably 1.0.2. And yeah, the radial engines/tanks/legs remain on Duna.

[Sharpy]

How do you guys live with a dedicated reaction wheel on something so tiny?

I tried something similar. SAS would drain my battery in ten seconds flat, wiggling it around using the reaction wheel, and if I so much as tried turning it around, I'd enter a wild spin. Normal probe core with 0.3kNm torque, okay. But that thing has 5kNm. Limiters? Analog joystick?

[Tatonf]

The small inline reaction wheel consumes 15/min and the pod 1.8/min for a total of 16.8/min ; while a single OX-STAT provides 21/min, so you shouldn't have any problem with electric charge. Duna is not far enough to have problems with photovoltaic panels.

I don't use any limiter, just engage the SAS and it should be ok. It's true that this reaction wheel is overpowered for this kind of craft but it's totally doable.

Howerver here's a tip : if you press Caps Lock you can enable smooth controls.

Edited July 17, 2015 by Tatonf