Dropping rectangular heavy objects onto Duna without breaking them...

[Skorpychan]

So. I am, currently, attempting to drop a large rover onto Duna, but there are some issues with the skycrane solution I tried on the Mun. Mainly that it didn't get there with a prior attempt, and went crazy when I throttled the skycrane up.

Having ditched the skycrane idea, I went with boosters on each end of it. The rover is basically two hitchhiker containers, a 6-way connector in the middle, and wheels on girders attached to the sides.

The booster solution is an FLT-400 tank on each end with a couple of the big radial engines on each tank, and another FLT-400 on the top to act as a mast for the intricate web of struts to stop the thing wobbling like crazy, and feed fuel to the booster tanks.

One drogue chute on the top, four radial chutes on each hitchhiker container, landing legs on the outer axles.

My questions are:

Is that enough boosters and chutes to land safely on Duna?

Will four sepratrons fire the empty mast tank upwards and give enough time to get the rover out from underneath it?

How do I make sure the drogue chute doesn't make it slam back into the rover?

Should I just dump that section on the way down and fire it off at an angle?

Should I mount tanks and thrusters on the middle as well?

Is it just going to fall apart despite the web of struts?

[blizzy78]

The rover is basically two hitchhiker containers, ...

Uhh, please post a picture. It says more than a thousand words.

Is that enough boosters and chutes to land safely on Duna?

That would depend simply on thrust to weight ratio, if not for the parachutes.

Will four sepratrons fire the empty mast tank upwards and give enough time to get the rover out from underneath it?

Also depends on the TWR. If they can fire the tank away on Kerbin, they definitely can on Duna. You can also attach them in an angled way, so there wouldn't be any need to drive out just in time.

[Skorpychan]

Uhh, please post a picture. It says more than a thousand words.

That would depend simply on thrust to weight ratio, if not for the parachutes.

Also depends on the TWR. If they can fire the tank away on Kerbin, they definitely can on Duna. You can also attach them in an angled way, so there wouldn't be any need to drive out just in time.

It's more a case of driving out before the thing comes slamming down on top of the rover.

[NGTOne]

I think your problem is the drogue, to be honest. Is it deploying as you come down through Duna's atmosphere, or once you're already on the ground?

[Skorpychan]

I haven't even got this thing to Duna yet. It's meant to deploy in the air on the way down, to slow everything down.

[KerbMav]

As blizzy78 said, angle some of the sepratrons at a slight angle to give it sideway momentum away from your drop zone.

The action groups should give you the option to cut the chutes as you separate the thrusters - so use an action group and not staging for this.

Do you want to keep (and repack) the parachutes on the rover for any reason? Else I would put them on the center stack below the drogue - and Id add two drogues and more chutes on the thruster modules - shoot it all straight up high on Kerbin and test its stability as the chutes open, could be to much force this way.

You might at least want to put the tanks in the middle - mass will be more centered that way which is also good during ascent and travel and it might also flex less when the chutes open.

To test the various stages you can also save the craft in a different file, take it apart and e.g. let it drop from launch clamps to test its stability when dropped from a few meters.

Aesthetics question: Do all the struts start out from the parts that will detach from the rover? Else they will leave pock marks. Asked just to be sure.

[Skorpychan]

Aesthetics question: Do all the struts start out from the parts that will detach from the rover? Else they will leave pock marks. Asked just to be sure.

Yup, they all run TO the rover, not from.