Building a lander *around* an ascent module... how?

[ImThat1Guy]

I think what I want to do can best be summed up by the (much more elaborate) KSP Constellation crew module. Really, I just want to leave a bit behind, like the Apollo Lunar Module, but use the same engine for descent and ascent. The Soviet LK is probably the best real-world counterpart. Unfortunately, I can't manage to build it without stacking it (defeating the purpose) or using radial decouplers (defeating the other purpose, as the lander wouldn't stay together once the AM leaves).

So yeah, if any of you have ideas for how to accomplish that, I'd be grateful. I'm currently using B9 and KW Rocketry, if that matters remotely.

[Vanamonde]

Why don't you download Katateohi's ship and disassemble it?

[astropapi1]

If the devs hadn't made the decouplers completely solid objects, it would be incredibly easy to do this...

[Alchemist]

Has anybody tried making a decoupler with hollow collider? (that is multiple collider meshes forming a ring - that should be possible with Unity)

Another probable option might be a decoupler allowed to intersect other colliders configured so that engine's thrust origin is inside (but that can result in some other problems, that is excessive kick on separation)

[Kasuha]

I think I used something like that with my Eve lander.

Landed module:

Remnant:

[ImThat1Guy]

He uses tons of mods that I really don't want to install just to look at one craft.

EDIT: Forgot to hit reply with quote and I'm lazy.

Edited February 15, 2014 by ImThat1Guy

[BlazeFallow]

One idea:

On your ascent module: put a standard decoupler in the center on a hardpoint, radially attach to the hardpoint two descent/ascent engines. then on the decoupler just attach whatever your descent/lander stage would be. That way, when you decouple, you leave the decoupler behind, with all that is attached to it.

The bottom of the design would look something like this:

                  \  E  /
                  [==D==]
                  /  E  \

Since you'd be attaching things to the side of the decoupler and nothing beneath it, it leave the engines free to fire on both the descent and the ascent. You could even set it up so that the descent stage had fuel tanks with fuel lines that fed into the ascent stage, so as per normal fuel consumption rules, the descent tanks would be used up first.

[Anton P. Nym]

On your ascent module: put a standard decoupler in the center on a hardpoint, radially attach to the hardpoint two descent/ascent engines. then on the decoupler just attach whatever your descent/lander stage would be. That way, when you decouple, you leave the decoupler behind, with all that is attached to it.

Just knocked out a quick version; the ascent stage (with lander can, tankage, instruments, RCS, etc) had a pair of radial-mounted engines on an FL-T800 fuel tank and the docking adaptor above was just engaged with the bottom of the tank. That arrangement needed fuel lines from the tanks left behind to the ascent stage. It's doable this way; not sure if that's quite what the OP'd intended.

-- Steve

[BlazeFallow]

--image redacted--

Just knocked out a quick version; the ascent stage (with lander can, tankage, instruments, RCS, etc) had a pair of radial-mounted engines on an FL-T800 fuel tank and the docking adaptor above was just engaged with the bottom of the tank. That arrangement needed fuel lines from the tanks left behind to the ascent stage. It's doable this way; not sure if that's quite what the OP'd intended.

-- Steve

Yes, that is very similar to what I had imagined. That's about the only way I can think that you could do this and still have the descent stage remain intact upon decoupling, since multiple parts attached to multiple radial decouplers would break any struts that attach them all together.

[Zephram Kerman]

Has anybody tried making a decoupler with hollow collider? (that is multiple collider meshes forming a ring - that should be possible with Unity)

Not sure about this, but I think a collider mesh is not allowed to have any concave angles. So, for example, the toroidal fuel tank is actually not hollow, but allowed to clip.

Just a few weeks ago, I had a similar inspiration as ImThat1Guy to make an Apollo-style lander. I want to use the same engine for descent and ascent, and leave behind some hardware that doesn't fall apart upon separation. After about a dozen failed ideas, this thing emerged:

Unfortunately, the technique is tricky and fiddly. But after the first version, the second one was almost easy. The descent module is connected to the ascent module by four Jr. docking clamps. The four clamps on the ascent module are symmetrical. The clamps on the descent module are not. Instead, the root part for the descent module is the clamp on the right. The whole descent module was built radially from that point, in the shape of a C. (Or maybe a Q, if you count the one strut to close the other end of the circle.)

Below, you can see the root part Jr. clamp, while the other three clamps are deleted for clarity.

The fiddly part is getting the other three ports to line up. I did that by a combination of tediously tweaking the trusses and drop tanks, in addition to the Jr. clamps above. After some doing, all four clamps line up closely enough that they automatically dock on the launch pad.

To separate, I used an action group to combine the engine toggle with all the Jr. clamps. Use it once to deactivate the engine, throttle up, then use it again to activate and undock.

Edit: here is the .craft file. MessengerIII

Edited February 15, 2014 by Zephram Kerman

[ImThat1Guy]

http://img.photobucket.com/albums/v338/sumpca/Kerbal%20Space%20Project/KSP_Legacy_LandingStage_zps855f72d6.jpg

Just knocked out a quick version; the ascent stage (with lander can, tankage, instruments, RCS, etc) had a pair of radial-mounted engines on an FL-T800 fuel tank and the docking adaptor above was just engaged with the bottom of the tank. That arrangement needed fuel lines from the tanks left behind to the ascent stage. It's doable this way; not sure if that's quite what the OP'd intended.

-- Steve

Not quite, unfortunately. I'm adapting my orbital crew vehicle (think Orion in real life) into a Munar/Minmal/maybe Dunar lander. It just has one in-line engine.

Not sure about this, but I think a collider mesh is not allowed to have any concave angles. So, for example, the toroidal fuel tank is actually not hollow, but allowed to clip.

Just a few weeks ago, I had a similar inspiration as ImThat1Guy to make an Apollo-style lander. I want to use the same engine for descent and ascent, and leave behind some hardware that doesn't fall apart upon separation. After about a dozen failed ideas, this thing emerged:

Unfortunately, the technique is tricky and fiddly. But after the first version, the second one was almost easy. The descent module is connected to the ascent module by four Jr. docking clamps. The four clamps on the ascent module are symmetrical. The clamps on the descent module are not. Instead, the root part for the descent module is the clamp on the right. The whole descent module was built radially from that point, in the shape of a C. (Or maybe a Q, if you count the one strut to close the other end of the circle.)

https://dl.dropboxusercontent.com/u/78157466/forum%20posts/Messenger%20IIIa.jpg

Below, you can see the root part Jr. clamp, while the other three clamps are deleted for clarity.

https://dl.dropboxusercontent.com/u/78157466/forum%20posts/Messenger%20IIIb.jpg

The fiddly part is getting the other three ports to line up. I did that by a combination of tediously tweaking the trusses and drop tanks, in addition to the Jr. clamps above. After some doing, all four clamps line up closely enough that they automatically dock on the launch pad.

To separate, I used an action group to combine the engine toggle with all the Jr. clamps. Use it once to deactivate the engine, throttle up, then use it again to activate and undock.

Edit: here is the .craft file. MessengerIII

This is something I might be able to work with. Thanks!