How to remove the decoupler from the bottom stage afterwards?

[Kulebron]

I made a ship in which the top stage is a lander. I decouple from the orbit module and descend. But the decoupler stays on the orbit module, and I can't dock to it on return. A docking port is not quite possible, because I have an engine there or just don't want to carry a docking port in the bottom and spend more fuel.

What are the ways to drop it? Or another lightweight design that lets you dock afterwards?

Why need to dock? To transfer the extra fuel from the lander into the orbiter for more safety margin on return.

Edited September 6, 2013 by Kulebron

[Awaras]

You can't drop the decoupler once you start the mission...

The stack separator will decouple from both parts it connects simultaneously and just drift off.

On the other hand, you can make the two ships already 'pre-docked' in the VAB and not use any decouplers or stack separators at all...

Also, you can use a single docking port the same way you use a decoupler - you can connect anything to the docking port and it will 'undock' from it once you select the 'undock' option from the right click menu. This is a one time thing, of course. You can't re-dock the other thing later unless it has a docking port of it's own.

Edited September 6, 2013 by Awaras

[Captain Sierra]

Use a stack separator, the blue decoupling parts. They separate on both sides and are exactly what you need right there.

[blizzy78]

It looks like you're doing it Apollo-style - which forbids the pre-docking in the VAB, mind you - and have a docking port right below the decoupler. You can also right-click the docking port and select "Decouple Node". That should separate the decoupler from the craft.

[Awaras]

It looks like you're doing it Apollo-style - which forbids the pre-docking in the VAB, mind you - and have a docking port right below the decoupler. You can also right-click the docking port and select "Decouple Node". That should separate the decoupler from the craft.

I think that's a SAS module under the decoupler in the image, not a docking port. Unless I am mistaken...

*edit* No, my bad... That's a docking port. Yeah, just right click/decouple node... He didn't even NEED a decoupler there then.

Edited September 6, 2013 by Awaras

[Kulebron]

^^ I did need a decoupler, because the LM stood the other way around. I'll try your options, thanks to all

I think maybe I could undock the service module from the decoupler, forgot about this option, thanks!

[Awaras]

^^ I did need a decoupler, because the LM stood the other way around. I'll try your options, thanks to all

I think maybe I could undock the service module from the decoupler, forgot about this option, thanks!

But that's the point, the single docking port (not two docking ports put together) acts exactly like a decoupler. The only difference is that you have to manually separate it through the right click menu instead of through staging.

[mellojoe]

Flip the decoupler upside down. The red triangle on it needs to point the other way. The flat part of the triangle shows the part that it will stay attached to when you decouple.

[Dedjal]

use a blue one or stick the yellow one the other way around.

[Mr Shifty]

But that's the point, the single docking port (not two docking ports put together) acts exactly like a decoupler. The only difference is that you have to manually separate it through the right click menu instead of through staging.

The other difference is that delta-V calculations in MJ or KER won't be correct unless you use decouplers.

[Kulebron]

A decoupler upside down is an interesting idea.

And I use Flight Engineer plugin which calculates delta-v. Although when you try to assemble an Apollo-like spacecraft, it fails to calculate the delta-v. I'm not sure if it handles fuel pipes correctly.

Any idea how to test the hardware without flying to the orbit? If I put an engine above the upside-down decoupler, will it shoot through it?

[maltesh]

The other difference is that delta-V calculations in MJ or KER won't be correct unless you use decouplers.

Docking ports also allow fuel flow through them unless you disable it on the pad, which can result in upper stages draining unintentionally. In addition, if you let mechjeb auto-stage and aren't careful, it will happily light stages above a docking port until its sequence hits a decoupler, the results of which can be somewhere between annoying and catastrophic.

[sojourner]

A decoupler upside down is an interesting idea.

That will just result in the decoupler stuck to your engine instead of to the docking clamp. Besides, there are 2 good answers already in this thread.

1. after using the decoupler, rightclick on the docking node it's attached to and click "decouple node" to release the docking clamp.

2. use a stack seperator next time, it has blue markings and detaches from both ships when activated. It functions in all other ways as a decoupler as far as ENG and Mechjeb are concerned.

oh, and third option just omit the decoupler and drop the upper ship right on the docking node and then "decouple node" as above.

[Tank Buddy]

You have to use on of the blue decouplers because they detach from both sides, although you may have to maneuver away from them as they just float.