18t (or less) Returnable Manned Mun Lander

[Pecan]

I haven't even got the faintest idea what funds you start with in career mode, it's a silly distraction from rocket design as far as I'm concerned. Here are the screenshots though:

Leftmost is completed contracts (there are no failed/cancelled - I'm not that shallow).

Middle is active - those I've taken for the advance but haven't yet completed.

Right are contracts available, not not accepted, at the moment.

This is ~45m into the game, when the first mission has landed and been recovered.

@5thHorseman - there is 'enough' ^^ science from the initial crew-reports and launch/5,000m/atmosphere/orbit contracts to unlock a fair bit. The rest of the unlocks came, mostly, when I'd landed. The point remains - spend 'whatever' as soon as you can. In the middle of a mission it might make a whole new set of possibilities available (such as all the EVAs).

Guys - suck it and see :-)

Stuff we can all agree (probably):

1 - You start with 'launch new', '5,000m', 'leave atmosphere' and 'orbit' contracts.

2 - A pod, parachute, 10xFL-T200 fuel tanks and T30 is plenty to make orbit and back (if you know how to fly).

3 - You can only accept 2 contracts at the start

Edited December 20, 2014 by Pecan

[Renegrade]

There was exactly ONE 'science from space' contract during my first mission, and even that was probably just lucky. I certainly wouldn't want to bank on it again. The visual contract was an entirely unexpected one and I'd think the chance of that was practically zero - it lterally appeared between my de-orbit burn and re-entry.

That visual survey was the chance one, 'science from space' appears all the time. One of my early vessels is this:

It's for a stock FAR world, although it really only needs a tiny bit more delta v to work in pure stock (the smallest 1.25m liquid fuel tank would be enough).

It can transmit 28 reports before running out of power.. if I get into a cash squeeze, I just cancel the one-star contracts until "science from kerbin orbit" appears and instant free money~

(later I replace it with a probe core solar power satellite with a thermometer on it. I fondly imagine that they're weather sats or long term experiments, heh)

[Pecan]

That visual survey was the chance one, 'science from space' appears all the time...

Ah right - I don't usually do career mode as it's so complicated and insane.

Erm, your ship isn't exactly 'start tech', is it. I'm in the wrong discussion I think (yours is right, mine isn't) but I've been saying what I did with tech-0, mission-1.

[Superfluous J]

Oh yeah I can get to orbit on the first launch no probs. I don't even bring a parachute. My concern was getting enough cash and - what I consider harder - science to do all that you said you could do. From what you've said though I think I see it and next time I play I'll give it a shot. I love the "Do the most you can with the least you can get" stuff, makes designing missions and rockets more fun IMO.

Edited December 20, 2014 by 5thHorseman

[thyriel]

Are upgrade costs cheaper in lower difficulty settings or something? Because there's no way to grab 64k from the advances on those contracts on Hard.

Yes, they scale with the Funds penalty setting

[Renegrade]

Erm, your ship isn't exactly 'start tech', is it. I'm in the wrong discussion I think (yours is right, mine isn't) but I've been saying what I did with tech-0, mission-1.

Actually the whole thread is veering kinda off-topic from the 18t Mun lander.. it's still talking about getting stuff done with low tech buildings so it's not too far off though

The ship is fairly low tech, it's all doable in the tier 1 (tier 0? -- the un-upgraded/initial buildings) building limits, but it does require a few science node purchases (all available within first tier buildings). The BACC could be replaced with two-stage RT-10 solution, reducing the science requirements a bit, and if FAR isn't involved, the tailfins aren't necessary at all.

From what you've said though I think I see it and next time I play I'll give it a shot.

I performed Pecan's mission in a pure-stock game, and it did indeed work as he said. I fell a bit short science wise, but that's because I forgot to take science after landing.

Yes, they scale with the Funds penalty setting

Yep, plus with default hard settings, you have to unlock items in the science nodes with cash, which is quite costly..

[WanderingKid]

Ah right - I don't usually do career mode as it's so complicated and insane.

Erm, your ship isn't exactly 'start tech', is it. I'm in the wrong discussion I think (yours is right, mine isn't) but I've been saying what I did with tech-0, mission-1.

It's not horribly offtopic, I'd think, Pecan. You're still discussing something under 18t! But yeah, the original question was really how to get to Mun without upgrading the Launchpad or other buildings. At this point that's been discussed/solved, so, Tech 0 away!

[samstarman5]

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)

Forgot how spoiled one can be with patched conics, until we are suddenly without them at the start of the new career mode. Most of us who started KSP early on learned the trick to a free-return trip to the Mun without using PC's. On a pro-grade orbit of Kerbin, best done under 100k, you aim for the Navball horizon, and then begin your burn just as the Mun appears from behind Kerbin. I don't know the speed to shoot for, but in the map you kill your thrust just as the trajectory breaks past the Mun's orbit. That should give you a nice return straight to Kerbin's surface, though it will always be easy to make corrections along the way.

Of course, if atmosphere re-entry ever becomes dangerous in the stock game, then this tactic will need revising, as your descent will certainly be way too steep to survive. Even before the effects were implemented, one only needed to watch the g-forces upon re-entry and cringe.

[Superfluous J]

Forgot how spoiled one can be with patched conics, until we are suddenly without them at the start of the new career mode. Most of us who started KSP early on learned the trick to a free-return trip to the Mun without using PC's. On a pro-grade orbit of Kerbin, best done under 100k, you aim for the Navball horizon, and then begin your burn just as the Mun appears from behind Kerbin. I don't know the speed to shoot for, but in the map you kill your thrust just as the trajectory breaks past the Mun's orbit. That should give you a nice return straight to Kerbin's surface, though it will always be easy to make corrections along the way.

Of course, if atmosphere re-entry ever becomes dangerous in the stock game, then this tactic will need revising, as your descent will certainly be way too steep to survive. Even before the effects were implemented, one only needed to watch the g-forces upon re-entry and cringe.

Yeah I've done the "no maneuver node to Mun" thing (though I never did a free return without seeing it shown with patched conics, and from what I have seen with them successful return is very touchy and dependant on exact velocity and direction) but with early tech and a paper-thin fuel margin? I'll pass.

Also remember, we were talking about pushing one ship with another, so you have to add "being ready to burn when the Mun rises by having the ships in exactly the right spot and on the correct sides of each other."

[katateochi]

Forgot how spoiled one can be with patched conics, snip*

Yeah!! That was quite a shock to the system at first! Transfer to Mun was easy enough, I was more freaked out by the return home without being able to see the return orbit.

btw thanks for starting this thread WanderingKid, its been a fun little project (sorry about my earlier post, I'd misunderstood the mission spec!)

So I've now got a craft that (I think) is on spec; it can be launched with all buildings still on tier 1 and make it to Mun's surface and back;

I actually found the part limit was more of a problem than the weight. It's 30 parts & I've got the weight down to 10.6 tons. Was easily able to make it to Mun's surface and back with a fair bit of fuel spare. Here's the craft if anyone wants to try it out

Once the jets and wings have been dropped the main rocket stage will get you into orbit and have enough to start the transfer burn. Main rocket stage has 4 Rockomax 48's and the lander has just 1. All fuel tanks are full except for the 2 small tanks with the jets, they're about 3/4 full of liquid and no oxidizer. I also emptied out the monoprop from the command pod, not sure if that made much difference but why not. I could probably do without the wings, but I've not tested it without them yet.

The part count limit was the main problem for me, but the editor gizmos helped to shave a few parts off without any need for f12 part clipping and made it possible to do things that in the past would have required more girders and part-clipping.

Rather than use 1 girder for each of the 4 engines on the main rocket stage, I attached an engine to the node at either end of a girder and then used the gizmos to rotate the engine 90 degrees and move it out from the girder slightly. When radially attaching the girder to the tank it's not quite symmetrical by default but by using the gizmos to move it one notch it got it spot on.

The engine on the lander was recessed inside the tank so it was flush with the bottom of the tank, that way I didn't need to bother with any landing legs and with the decoupler attached it looked nice and flush. That would have required a small cube part in the past.

I was really pleased with how they allowed me to place the jet engines. First the tank was attached to the radial decouplers as normal, but then I gizmo'd it 90 degrees. The Jet was then attached to the tanks node and also rotated 90 degrees. That would have been a really awkward thing to do in the past and would have needed at least another girder (probably 2).

[Yemo]

A great challenge thread!

@Katateochi: Thats a very nice design, especially using the offset construction for the very efficient Rockomax 48-7S.

I tried your craft without the wings and elevons, and it is really great. Will use that design when I m higher tech, thanks very much.

My VJR Mun focuses on low tech requirements, in its basic form it needs only 200 science invested (batteries instead of solar).

The standard lander makes it newbie friendly and there is some room for customization.

TWR is a bit high for the 5000m mark (about 190m/s instead of 160m/s), but ok for 10000m (260m/s). But with jets, there is no need to save fuel in lower atmosphere anyway.

Parts: 27

Mass: 15.7t

There are other low tech/low cost designs in that imgur album, if anyone needs some inspiration for a hard career. Best to open the album seperately for that, to see all info on the crafts.

Javascript is disabled. View full album

Edited January 5, 2015 by Yemo

[WanderingKid]

That's a great ship, Kata. A little under 11 tons? My word! How high/hard do you fly that in atmo? My own method ran into both part count and weight issues, but succeeded. I need to get better at doing things, but that's a different story.

Javascript is disabled. View full album

You can find the full mission movie on my Let's Play, here:

[panzer1b]

If youve unlocked EVA its 100% doable. Due to the well, exploit that lets you get a theoretical INFINITE dV using EVA kerbals, but with stock parts (and no ability to dock since docking ports are later game), i highly doubt its doable. Getting to the mun and back, i think could be done, but anything else is rather difficult. Assuming use of LV909s outside of atmo, you can easily get to mun, orbit mun, and get back with a 18t limit, but landing takes quite a bit extra dV (assuming you do it perfectly), so i dont think it can be done. So aside from exploits (krakendrives, eva kerbals, infiniglide), i highly doubt a 18 ton vehicle can get the necessary dV to do this.

Perhaps a SSTO could do this (i have a 18.4 ton SSTO thats laythe capable, i could easily cut down some of the fuel to get it below 18), but this would require LATE game parts, and the regula turbojet is only useful as a booster for a rocket.

Gues sit is possible lookin at earlietr posts, but wow, some of those thinsg are insane....

Edited December 20, 2014 by panzer1b

[WanderingKid]

It's doable, Panzer. Look at the post before yours. 100% stock, no EVA.

[Pecan]

...Perhaps a SSTO could do this ...

SSTOs are way less efficient than staged designs, why would you think one could do this in less mass?

[cantab]

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.

I completed a mission using this approach.

KSC upgrades: Astronaut complex (essential), Tracking Station and Mission Control (optional but make life SO much easier).

Tech tree:

In the end I needed four launches.

This ship took Jeb to the Mun then partway into Munar orbit, he finished on the jetpack.

This ship picked Jeb up from Munar orbit and brought him back to Kerbin orbit. It turned out to be the hardest to build. I had to omit parachutes to save weight, and it still didn't have enough delta-V to get into low Munar orbit, only a fairly elliptical one. And I still had to do a little bit of pushing, just enough to finish raising periapsis 70 km after the aerobraking passes.

Two of these ships went up and took the Mun-tripping Kerbals back to Kerbin.

Full mission album: https://flic.kr/s/aHsk73bfwz

PS: If you copy these ships, know that I tweaked a little fuel out of the first stages to bring them under the weight limit.

Now, can anyone do it on only the first two tech nodes?

[Janos1986]

I thought to send a probe on the mun too, then I remembered I have RemoteTech installed, signal delay and all.

It won't be easy.

[katateochi]

Thanks guys!

A great challenge thread!

@Katateochi: Thats a very nice design, especially using the offset construction for the very efficient Rockomax 48-7S.

I tried your craft without the wings and elevons, at it is really great. Will use that design when I m higher tech, thanks very much.

snip*

Ah cool, that saves me having to do that test run! nice 1. With those removed then you could put some of the small sci equipment on it once you've unlocked those.

I've used it on several missions now, went to Minmus and did all kinds of orbital adjustments to do visual surveys, landed and returned (and by sheer chance bulls-eyed a landing back at KSC, I was so pleased!)

That's a great ship, Kata. A little under 11 tons? My word! How high/hard do you fly that in atmo? My own method ran into both part count and weight issues, but succeeded. I need to get better at doing things, but that's a different story.

snip*

I took off and went straight up till 5km, then pitched to about 45 degrees and pretty much stayed at that pitch until I reached ~27km. At that point the engines sounded like they where about to flame out and I was beginning to loose vertical speed. So staged and then carried on at a 45 degree pitch for a little while before gradually reducing the pitch and going for a more classic rocket ascent profile. (I'm going to make a vid of the mission to Mun, just what with Xmass shenanigans I've not had time yet and I'm off for a week on Tue, but I might try and get it done tonight/tomorrow)

Theses are all really cool solutions, I like that we've all basically been thinking along the same lines in the designs. It's made me have a new found respect for the worth of the basic jet engines!

[WanderingKid]

27k? With just the radial intakes? How many intakes are you using? With 2 per, of course without wings so my intake path was rather different, I couldn't avoid a flameout past 18k or so. A 45 degree angle (vs. my 70 degree, putting prograde at 45 degrees) may make all the difference there.

[Yemo]

My ascent path uses the jets until about 28km, when they loose too much thrust to be efficient. They suffocate around 30km.

Key is not only the air intake to usage ratio (with one intake per engine, they suffocate around 20km), but also the speed (especially with basic jets) and the thrust to weight ratio.

You only have 2 jet packs for a weight similar to mine, thus relatively low TWR of 1.7 in the jet booster stage compared to my 3 jet packs with 2.9 TWR. But you carry much more fuel in the second stage which makes your design a lot more funds/cost efficient (and funds are in shortest supply when on hard mode), while mine is more energy/weight efficient.

Katateochi has much less weight, so he only needs 2 jet packs for a TWR of about 2.9.

Also there is some kind of bug. When I tried a setup with 1 fuel tank, 6 intakes around it and 3 jet engines below a tricoupler to save 1 part, they suffocated around 20km, as if they had a 1 to 1 intake to jet ratio. Specific intake/fuel placement seems to be somehow important.

Edited December 21, 2014 by Yemo

[cantab]

Yeah. The issue has to do with the intakes and engines being processed in the order they're in the craft/persistence file, meaning the order you place the parts in matters. In your case I think you'd want to place a pair of intakes then a single engine, and repeat that process.

[Greep]

Hey, just registered because I did something crazy stupid and just had to share it. Admittedly, this isn't a returnable manned, but it is an odd way of getting the mun contract fulfilled with very little science.

From top to bottom:

Antenna

16 batteries

thermometer

fuel

lv-909

decoupler

reaction wheel

fuel

lv-30 engine (or whatever it's called)

decoupler

srb

srb

Kinda surprised it was possible without solar panels, but my flight had over 300 extra power

Also, turns out stayputniks aren't all that bad at all, they just take a bit of getting used to. The trip to sub orbit requires a reaction wheel, and from there on out you can use a throttle limited lv-909 as a sort of makeshift rcs. Don't even try using a stayputnik's final stage with the reaction wheel still on.

[katateochi]

27k? With just the radial intakes? How many intakes are you using? With 2 per, of course without wings so my intake path was rather different, I couldn't avoid a flameout past 18k or so. A 45 degree angle (vs. my 70 degree, putting prograde at 45 degrees) may make all the difference there.

Yeah the pitch makes a big difference, more time in the atmo gaining more speed which then helps them work better at higher alts. I just had two per engine also. It was an odd ascent profile, not quite like a rocket, not quite like a plane, somewhere in-between.

With turbo Jets I would have pitched down lower as they still perform well high up, but with the basic jets there was a trade off between gaining surface speed while also keeping a good vertical speed so by the time I dropped them I was still going up around 100m/s.

*snip

Key is not only the air intake to usage ratio (with one intake per engine, they suffocate around 20km), but also the speed (especially with basic jets) and the thrust to weight ratio.

snip*

Yeah exactly! With my very small SSTO aircraft they can run on Jets right up to around 36-37km because they are going so darn fast by that point! I guess that's kinda how RAM jets in RL work?

Also there is some kind of bug. When I tried a setup with 1 fuel tank, 6 intakes around it and 3 jet engines below a tricoupler to save 1 part, they suffocated around 20km, as if they had a 1 to 1 intake to jet ratio. Specific intake/fuel placement seems to be somehow important.

Yeah. The issue has to do with the intakes and engines being processed in the order they're in the craft/persistence file, meaning the order you place the parts in matters. In your case I think you'd want to place a pair of intakes then a single engine, and repeat that process.

Oh, interesting. I'd never noticed that issue before. I never pay that much attention to the order that parts are added. And I'm always ripping bits off and re-positioning them, I wonder if doing that has saved me from seeing that issue before.

[katateochi]

Hey, just registered because I did something crazy stupid and just had to share it. Admittedly, this isn't a returnable manned, but it is an odd way of getting the mun contract fulfilled with very little science.

snip*

Even thou its unmanned and non-return, it's still a nice solution to getting that contract done on the cheep though. Also, Welcome to the forums!

[xcorps]

Yeah. The issue has to do with the intakes and engines being processed in the order they're in the craft/persistence file, meaning the order you place the parts in matters. In your case I think you'd want to place a pair of intakes then a single engine, and repeat that process.

I like to use the tricoupler with jet engines with the small rocket fuel tank stripped of oxidizer and reduced fuel for an insane TWR up to about 10k. Get an AP of about 40k and the jets run out of fuel before they get air starved so there is no air starvation craziness. You get waaaay over Terminal, but you can control your next stage burn so that you save a ton of Dv.

Saves a lot of headaches that way, you only need one air intake and it isn't something you have to monitor since you are only getting to the gravity turn with them.