Help Caelus II Land On Mun!

[Undy]

Caelus landed on Mun. Or rather, Caelus ran out of fuel and crashed in a ball of fiery disaster. A top-down redesign was required for Caelus II, including a larger, more functional rover. This presented... Difficulties.

The current configuration of Caelus II lacks the firepower required to reach Mun, but is the stablest configuration I've had for her yet. I figured adding an extra fuel tank and poodle engine into the midsection might help, but this led to the whole thing glitching out, with solid boosters refusing to fire and launch supports refusing to detach. I checked and double-checked the staging, but had to revert to the previous design.

Is anyone willing to help me out with this? Even without the lack of firepower, the design is lacking in a couple of places - the disconnect between the midsection and the underside of the rover/lander (designed to be an all-in-one to land the rover, explore around, then fly back up to reconnect with the orbiting manned section) isn't great, and the section around the rover could probably do with a bit of extra stiffening. I want to get the rover onto Mun, look around for a bit, then re-attach and return to Kerbin, but I'm really running out of ideas to improve the design that don't result in an uncontrollable wreck.

Caelus II can be downloaded here.

[Kegereneku]

That's one of the craziest design I have seen.

I can't really give you tips, because I don't understand why you would design the rocket like that, nothing make any sense.

I don't think it can reach Kerbin Orbit

It don't have enough DeltaV to reach the Mun anyway.

In any case this is far from optimal (and staged like this the main thruster don't activate at launch)

Edited June 11, 2013 by Kegereneku

[Cranium]

How on Kerbin does that get into the air?

[Undy]

I've had it reach Kerbin orbit and it's reasonably stable from launch. The wacky design comes from me having no idea how to use the available parts to best lift and deploy a rover. I've seen plenty of nice rover designs but no real deployers for them.

[Nibb31]

1) Make the lander stage smaller. A single grey tank and two radial engines should be enough you need.

2) Add a stage underneath the rover for the Kerbin departure and Munar orbit insertion burns.

3) Your mainsail core stage is ok. Get rid of all the SRBs and replace them with liquid boosters, identical to your core stage, arranged in asparagus style.

4) Why SRB's on top?

5) Why winglets on an upper stage? They serve no purpose in space.

[Undy]

The actual lander section is within the body of the rover - an FL-T200 fuel tank with eight 24-77 radial engines. The section above was intended to remain in Mun orbit, awaiting the return of the rover (no idea if the eight 24-77's is enough to lift back into a low Mun orbit). As you can see, I tacked on an extra fuel tank in the hope of getting a bit of extra performance.

When I added a stage beneath the rover before (X200-32 tank and poodle engine) the whole thing went to pot with various boosters refusing to fire etc. A ground-up rebuild should probably fix this though.

From what I've seen, the turbojet engines give good performance getting the main section out of atmosphere - should these be replaced with asparagus'd liquid boosters too?

The SRB's on top... Well, we can all have a good laugh about them. Initially they were intended to raise the centre of thrust on lift-off, but the whole thing was arcing at about 500m and heading for the sea. Angling them on the top capsule was an exercise in the absurd born out of frustration while actually resulted in a very stable launch. I still have no idea why a perfectly symmetrical lifter (I tried with something a lot smaller than you see there) would arc on lift-off, but arc it did.

The winglets on the upper stage are there to help with control on the return journey. Perhaps I'll focus on getting to the destination first though

[Johnno]

I think it's kind of genius in a way, using a rover as descent, exploration and ascent alltogether. Some thoughts from just looking at the images; too many RCS thrusters on the rover. One cluster per side should be enough (4 total). Could use RCS on the 'top' (mun insertion/return) stage as well. As remarked about winglets, I'd put them on the mainsail launch stage, can't use them in space and by the time you're returning to Kerbin you'll be coming hauling down opening parachutes. I hope? Wait I don't see parachutes on your staging list... guessing you want to return the rover in one piece? I'd still opt for parachutes on the command pod (and rover in that case).

A single FL-T200 tank may or may not be enough for landing the rover on the mun, but from personal experience I'd say extremely unlikely to get you back up again. 8 radial 24-77 is overkill, at least with your lightweight design, 4 (potentially 3 or even 2) should be enough. I'd see about cramming some more fuel into the rover, Oscar-B tanks and the round gold stackable tanks probably since I don't think there's room for anything bigger.

Beyond that there's heaps of ways to land stuff on the Mun, radial tanks&engines straight on the rover, a skycrane design, a larger lander with the rover underneath.. and even larger lander with two identical rovers on the sides, land the rover in a box with a ramp, the list goes on. Really only your imagination and time spent with design/testing that's the limiting factor.

To give you some ideas, here's two rover landers I've built. First one is for atmospheric insertion, but the general idea should be applicable.

This second one landed on the Mun, I was amazed that it was actually the most stable thing I've ever landed.

The white tanks were attached to the rover's frame with decouplers, each had two 24-77 engines and a landing leg. Simply decoupled once on the ground (although I flew/hopped to get closer to my intended site before I ran out of fuel).

Hope that helps you a bit at least.

[Undy]

Yeah, I'm needing to make some serious changes to the rover. I got the command pod into a low Mun orbit then released the rover, but only managed to slow down the tangential velocity to about 120 m/s before running out of fuel and mono. Another less-than-impressive crash landing. Even attempting to reconnect with the command pod was an exercise in futility. Then efforts to return the crew to Kerbus ended with them endlessly circling the sun. Which was supposed to be the role of the Icarus series of probes. Still, much further forward than yesterday.

EDIT: I'm going to call this rover a write-off. Completely incapable of landing on Mun at anything other than utterly destructive speeds. At least on the second attempt the crew made it back. I think Caelus IV will be a bit less ambitious about retrieving the rover. If I can get something there that can just land safely I'll be happy.

Edited June 12, 2013 by Undy