18t (or less) Returnable Manned Mun Lander

[WanderingKid]

Has anyone had any luck creating a Mun Lander in 18t or less? I can get the fly-by. I can get an OKTO lander down. I can't get a manned mission down and back up again yet, not without EVA Thrusting.

I keep coming up ~700 m/s short in my calculations on how to get in and out again.

Edited December 19, 2014 by WanderingKid

[RocketPilot573]

It took me 20 minutes just to figure out how to get to orbit with 18 tons (SRBs may be cheap, but they are heavy!).

I'm not sure that a Mun lander is possible with only early career stuff. Maybe if you used a jet engine for the launch stage?

[xub313]

I got an unmanned sample return with 18 tons. A manned lander might be possible with high tier technology.

[Captain Sierra]

It took me 20 minutes just to figure out how to get to orbit with 18 tons (SRBs may be cheap, but they are heavy!).

I'm not sure that a Mun lander is possible with only early career stuff. Maybe if you used a jet engine for the launch stage?

Throw the 30 part restriction on there too why don't we. Combine those two and is it possible? I don't believe it is.

[WanderingKid]

I can't get near 30 parts in 18t without throwing on a bunch of excess. My current attempt runs 22, and that's with 4 24-77's to help with TWR at liftoff.

[GigaG]

Could a Minmus lander be worked out within these restrictions? You might not get the contract, but you do get extra science compared to the Mun (I think) for less delta-v. Of course, you DO kinda need the contracts...

[WanderingKid]

Best I've gotten, dV wise, is ~6,720 dV. Problem is it has TWR (starts at ~1.7 TWR) issues during liftoff and loses a chunk in Isp to my additional boosters, so it's really ~6,420 dV.

You're not doing a manned landing at either with that. You can pull into orbit, but you're not leaving again. If you've opened up EVA you could extreme land it, refill mono at the capsule, and send yourself home for a rescue ship, I suppose.

Edit: Note, OKTO is .1t, MK1 Pod is .84. Unmanned landers/satellites are a bunch easier to get dV for.

[Superfluous J]

If you could drill up to docking ports this would be trivial.

Without them, you could launch your lander into LKO, then launch a transfer stage with a bowl-like front so it can get up against the lander and then push it into a transfer orbit. Then, if necessary, the bowl could slow it down again or the lander could have the dV to slow itself down.

[WanderingKid]

If you could drill up to docking ports this would be trivial.

Yeah, part of this I feel is being able to do it before you get past the Tier 5 Science Components. Upgrading the pad is 10x cheaper.

Without them, you could launch your lander into LKO, then launch a transfer stage with a bowl-like front so it can get up against the lander and then push it into a transfer orbit. Then, if necessary, the bowl could slow it down again or the lander could have the dV to slow itself down.

This... has possibilities. Use a probe ship to 'push' the other ship. Rondevous with no upgrades is always fun, but definitely an interesting technique. The pushing ship though is a suicide run, unlikely it'll have enough to slow down and return.

[Superfluous J]

Yeah, part of this I feel is being able to do it before you get past the Tier 5 Science Components. Upgrading the pad is 10x cheaper.

This... has possibilities. Use a probe ship to 'push' the other ship. Rondevous with no upgrades is always fun, but definitely an interesting technique. The pushing ship though is a suicide run, unlikely it'll have enough to slow down and return.

You may be able to free-return-trajectory it. (EDIT: Ewwww, not withtout patched conics you're not. Planning that by hand and executing it without game feedback would be a real bear)

I almost want to try this.

Actually I do want to try it.

"No-upgrades mun mission, lowest tech wins"

Edited December 19, 2014 by 5thHorseman

[Kesa]

If you're 700 m/s short, I guess you can almost land but not come back.

Why not land a engineer/scientist on EVA, plant a flag and send a rescue mission, say... later...

[Stormweaver]

Doable. Barely...with the fuel line node unlocked.

Didn't think to take a screenshot, but off the top of my head the stages going backwards:

- Mk-1 command pod, 1t fuel tank, tiny rockomax, small parachute

- 2x 2t fuel tank, radial decoupler, fuel line, tiny rockomax

- 2x 2t fuel tank, radial decoupler, fuel line, tiny rockomax

- 2x 2t fuel tank, 0.5t fuel tank, radial decoupler, fuel line, tiny rockomax

I cut it pretty fine - about 5 units of fuel left - but it wasn't the most effiecently flown mission.

Yay for asparagus?

EDIT: Grabbed the screenshot, with VAB readout (and fixed the above >.<):

Edited December 19, 2014 by Stormweaver

[WanderingKid]

So, Stormweaver, you radially attached all that stuff and fed it into the single 48-7S? How'd you get it orbital?

[Stormweaver]

So, Stormweaver, you radially attached all that stuff and fed it into the single 48-7S? How'd you get it orbital?

It did have 7 engines, I just forgot to type out the last...6. heh. Image above now.

[WanderingKid]

Curious. I was just working on a design with a similar theory... Not quite as round though.

Edit: Note to self: Do not launch to see Munrise when you're staring at the darkside...

Edited December 19, 2014 by WanderingKid

[cantab]

Just investigating does suggest it's tough.

It's definitely possible with Fuel Systems, which gives the 48-7S and the fuel lines. I came up with this guy:

Specs by cantab314, on Flickr

One caveat: I turned on debug menu clipping to make the engine clusters

Flew it on the Mun and back mission, though I did have patched conics and manoeuvre nodes. There's not a lot of room for error, though of course on non-ironman saves you can just retry until you get it.

It's also probably possible with Aerodynamics, giving you the Basic Jet and Radial Intake. A jet first stage will hugely slash your launchpad mass.

To do it without any 90 tech nodes is going to be much harder.

If you can EVA, which you probably can when you're considering a Mun landing, then you can do a two-launch Munar orbit rendezvous mission. One launch sends a kerballed ship that lands on the Mun and gets back into Munar orbit, but doesn't need to get back to Kerbin. That cuts the delta-V requirement by 270 m/s - not a lot, but every little helps, and you can save more if you use the EVA jetpack for the later part of the ascent.

The other launch sends a ship with a vacant seat that gets into Munar orbit, waits for the Kerbal who's coming from the surface, then takes them back to Kerbin. That one needs about 1300 m/s less than a direct ascent lander so is no problem.

Edited December 19, 2014 by cantab

[WanderingKid]

Ah, nice one Cantab. I hadn't thought to use the offset to use multiple 7S's.

215/30 (TWR is a killer)... 7 7S's... that's half the weight of the T30. Hrmmmm.... That's delicious.

[foamyesque]

Throw the 30 part restriction on there too why don't we. Combine those two and is it possible? I don't believe it is.

Hm. I've managed to get to Mun orbit from Mun surface on 30/18, but I was 230m/s short of return-to-Kerbin dV. There's some room for optimization... I didn't execute a particularly graceful landing and I think there's some excess weight I could lose. It's tight.

Unfortunately I'm using LV-Rs and a 24-77-assisted first stage, so that's not basic tech by any stretch.

Edited December 19, 2014 by foamyesque

[Renegrade]

One caveat: I turned on debug menu clipping to make the engine clusters

Er, does that let you surface mount a node-attach-only part like the 48-7S? O.o

EDIT: Ah, I see, the node comes back after attachment when part clipping is turned on (I generally avoid the part clipping option)... scary!

Edited December 19, 2014 by Renegrade

[Kesa]

One caveat: I turned on debug menu clipping to make the engine clusters

Kind of cheating reguarding that the games has radial engines and multicoupler (and cubic griders). But I must admit that the logic in which they appear in the tech tree does not makes sens for me, and that your cluster looks quite good

[Renegrade]

the games has radial engines

Oh! That reminds me, the Mk55 radial had a nice ISP buff - it's now 320-360 instead of 290-320. It's TWR is still kinda meh (same as T45), but it also had a gimbal range buff... I might actually use it for something now

Unfortunately the 24-77 is still the same as before..

[katateochi]

After MUCH testing and redesigning I've got a 14 ton manned aircraft that is a Single Stage To Mun Landing and Back (SSTMLAB). It's not a practical craft because it is extremely hard to fly right and I made things harder for myself 'cos I was determined that it was going to land VTOL style on Mun. So its 1 rocket engine (LV-909) is positioned for VTOL activities, which makes the ascent to kerbin orbit all the more interesting!

It can reach a 100km Kerbin orbit with up to 2700m/s dV spare but that takes ridiculously precise flying, I usually fall short of that. 2650m/s dV is the bare min once in a 100km orbit if it's going to make it back home again and that leaves almost no room for error in the rest of the mission. The ascent to LKO requires making tiny pitch adjustments (~0.2 degrees) so I use MJ's SURF function for that, aside from MJ its all stock parts.

Here's a KVV pic and a vid I made a couple days ago which shows a Mun and back mission and how to do the ascent from Kerbin;

Craft file on KerbalX if you want to give it a go.

[WanderingKid]

Nice Kata! You need to up R&D a level to get Turbojets but a nice craft anyway!

My best so far: Orbiting Mun and returning (with Aerobrake):

Note: You can't offset two 'centerline' thrusters onto the same axle. you have to use F12 to get the clusters of engines.

[foamyesque]

Righto, it's possible with a jet launch stage; I've got well over the needed 2600m/s dV in LKO at the moment. Using a landercan, intakes, and jets, though, so not as minimal-tech as you might hope. Should be possible with an ordinary Mk1 pod, however.

Edited December 19, 2014 by foamyesque

[WanderingKid]

Righto, it's possible with a jet launch stage; I've got well over the needed 2600m/s dV in LKO at the moment. Using a landercan, intakes, and jets, though, so not as minimal-tech as you might hope.

Did it with a Mk1 Capsule. I'm perfecting the 'ditch the jets' phase with Sepratrons. For the curious, 2x Jet Engines + 2 Radial intakes + 30 Liquid Fuel should get the rest of your bird up.