100% stock Mun mission designs and .craft files (version 0.13.x and 0.14)

[closette]

Hello everyone,

I had a lot of fun and learned a lot as a newbie by downloading some of the ships posted on here, so it\'s my turn to give back I guess. I cobbled this rocket together while I learned KSP over Xmas vacation. After yesterday\'s new release I had to reverse the fuel lines, but I left the rest alone even though it\'s a little untidy - as a newbie it would take me a long time to rebuild it from scratch.

Please take a look, play with it, and post and suggestions/improvements (including .craft files) below - 100% stock parts though! Here\'s the Munar Mission breakdown:

- jettison the solids after launch. It\'s best to stay close to vertical until pitchover at 24km altitude, or you\'ll be fighting for control and wasting RCS fuel (which we\'ll need for landing and return later).

- almost in orbit, the outer boosters run out of fuel first (the inner 3 boosters used the gimballed engines).

- Munrise, and we are GO for Trans-Munar-Injection! The 4 'hip'-mounted tanks provide plenty of fuel for the trip, with some left over for braking while modifying our Munar approach. Relax Bill!

- after Mun arrival and a bit of maneuvering to get to a desired landing area, it\'s time to jettison the 'hip' tanks, leaving one fuel tank for a controlled descent. Bill seems happier now.

- after getting rid of the descent engine at under 1000m (with plenty of fuel left if you want to hover around looking for a level spot), land with the RCS thrusters only. If something breaks on landing, you can still do a 'touch and go' with 12 RCS thrusters to lift you back up. Personally, as a klutzy girl, I found that 4 fins are much better than 3 when it came to absorbing the impact.

- lift off with the descent stage, point in the correct direction (270 degrees), then get rid of it, and fly home with two RCS tanks

- landing with two RCS tanks attached can be a little rough, so drain most of the remainder in the atmosphere, saving just a little to reduce touchdown speed to less than 8 m/s. Water landings are preferred but our intrepid three kerbonauts will survive this one just fine.

And there you have it! Looking forward to any constructive criticism, and hope this design proves useful/interesting to someone.

[Gojira]

Never tried a design like this!

Always used parts packs

[Cezary]

That is a fantastic ship. I have tried using RCS thrusters to land before, but I\'ve always failed. I also like 100% stock part ships and have designed quite a few Mun capable vessels. Check them out if you\'re curious @ http://kerbal.blogspot.com/

In regard to landing gear, I use Radial Decouplers and AV-R8 winglets. A single radial decoupler, attached as low as possible to a Liquid Tank, with an AV-R8 winglet attached as low as possible on the Decoupler will reach lower than the LV-T45 engine attached below the Liquid Tank. See below:

[closette]

Thanks for the kind encouragement Cezary, and for the landing gear suggestion. That might work for my ship, since currently I just throw away the descent engine + half a tank of fuel. Using the radial decoupler+winglet landing gear on that engine could allow me to keep it, land on it, and save more RCS fuel for the voyage home.

As for landing with RCS thrusters, it helps to have 12 (8+4) of them! With no throttle control you have to 'blip' them on and off, but the force of 12 thrusters seems well matched to the weight of my lander, and that helps a lot as long as you keep the speed under 20 m/s.

I\'ll definitely check out your blogspot site - glad there\'s another 'stock' enthusiast out there. (Nothing wrong with mods, I just prefer not to bother with them). Feel free to copy or link to my .craft file if you are collecting stock Munships on your site.

[Andras]

That\'s a very elegant design IMO. Well done.

[closette]

Very kind of you to say so Andras - it took a LOT of trial and error to get there, in the course of which I realized I was following a bunch of 1960s space-race milestones, i.e. Kerbin orbit, lunar fly-by (Zond 3), Ranger series (impacting the Mun), Surveyor (soft landing but 1-way trip), Apollo 10 (Mun orbit and return), and finally a successful Mun mission.

The 4-fold symmetry of the upper stages was shaped by my realization (trial and error) that I needed only 1 liquid engine but 4 side tanks and 4 fins for Munar transfer and landing, with the addition of enough RCS thrusters and tanks to complete the landing, and get back home. Of course the landing and return stages only work in munar gravity, so I could not test them on Kerbin first, which slowed their development.

I found that 6 liquid engines were needed to get the upper stages off the ground and into orbit (I started with 3, not enough). The rest was dictated by stability requirements and my klutzy lack of flying skills (I use a laptop with no joystick, if that\'s an excuse!).

If you\'ve been patient to read this far, I would also say that restricting myself to 100% stock parts actually helped me (1) learn a lot about orbital dynamics and delta-V budgets and (2) get a greater sense of accomplishment when I achieved a milestone. This is a very well-designed program in that respect.

[Scruce]

Water landings are preferred but our intrepid three kerbonauts will survive this one just fine.

Yes, water landings are preferred as there does not need to be any RCS fuel wasted during the re-entry stage.

Anyway, it\'s a great rocket, it reminds me of the UR-500 (Proton-K).

[closette]

Thank you Scruce for taking a look and your kind words and favorable comparison to the Proton! I\'m not worthy!

One of my spacecraft\'s weak points is that falling back to Kerbin from the Mun at >3000 km/s, with only RCS thrusters for maneuver, makes it hard to choose a landing spot! Thankfully most of Kerbin is covered in ocean.

My ideal landing site would be in water just off a beach - I can use any remaining RCS fuel to motor-boat to the shore.

Now that I can get the 3 boys back home reliably, I am experimenting with aerobraking into Low Kerbin Orbit, which might let me have a bit more control of where to come down, but will make for a much longer mission.

[Rickenbacker]

Very intresting, I\'ll have to try this out. I also prefer stock craft, and haven\'t been able to return my kerbals safely from the Mun yet... Maybe this will help.

[Rickenbacker]

Hey, it really works! I just got my first safe Mun mission and return! Had to do five orbits of aerobraking on the way back, because I used up all my RCS fuel to get home. But I landed safely on the tundra on the exact opposite side of the planet from KSC - on land! The capsule held out, and even Bill seemed happy to be home.

I like the hip mounted tanks. They gave me plenty of fuel to get to the Mun and mostly brake into a decent orbit. I then realized I had an entire tank left, so I just stopped dead and fell the rest of the way to the surface. I tried to land on the main engine, but it broke off (landed on a slight slope that I didn\'t notice from the 'air'). Still managed to straighten up the lander with RCS and land right next to the toppled main engine.

[closette]

Congratulations! I\'m so glad my design was helpful in achieving mission success!

Coincidentally I just completed an 'aerobraking' return - on purpose - which took a few orbits before reentry. Intentional or not, it\'s a much gentler way to return than just smashing into the atmosphere! Still hard to choose a landing spot though - and I hardly ever hit snow.

It sounds like you have the right idea, but what I do to to use the least fuel for returnin\' to Kerbin, is to cancel out the Mun\'s orbital velocity around Kerbin as much as possible when heading away from the Mun, so that when I leave the Mun\'s influence I end up falling nearly straight down back to Kerbin with a low periapsis to begin with. Then I immediately retrofire to lower the periapsis some more while I am still far away (and moving slowly).

As for the Mun landing, brave of you to try and land on a single liquid engine nozzle! But yes, with the slightest horizontal velocity will cause the engine to break off, and/or the entire spacecraft to fall over on its side. Glad you were able to recover in time!

I wish you many more safe returns, and please report back with any useful additions or changes.

[Rickenbacker]

Oh yeah, didn\'t think of that. I took of the wrong way, I think, so I ended up in a HUGE orbit around Kerbin on my return trip... Will go the other way next time .

[Rickenbacker]

Your creation inspired me to create something similar. It\'s basically a hybrid of your concept and one of my old landers. In theory it should be able to land on the main engine and take off using RCS, but I ran it out of fuel on the maiden voyage. I\'ll get there, though .

[closette]

Nice legs, Rickenbacker! (Lander legs that is).

I tried out your new spacecraft. It\'s funny how one gets attuned to one\'s own spacecraft and fuel budget, because with yours (13 Munraker) I did not have enough fuel to make it all the way down to the Mun\'s surface, even though by comparison, my MunandBack131A has only 1 set of solids not two, and more mass in RCS tanks and fins. On yours I lit both sets of solids off as soon as possible - should I have waited until higher in the atmosphere or is there a fuel strategy I am missing?

I also had some overheating problems with your lower liquid engine stage, but just backed off the throttle a little and was OK.

May I suggest that you use 4-fold symmetry for your lander (i.e. 4 hip tanks not 3, and 4 lander legs), and add an additional RCS tank to it? That would work better. I could modify your spacecraft myself I guess, but would appreciate it if you could provide a .craft file - once you\'ve tested it out of course.

Thanks for 'exchanging' spacecraft - that\'s what this part of the forum is for!

[Uri G]

Thanks closette I copied your creation and added a bit & made it to the Mun & landed (didn\'t quite make it back though). Cant quite get the hang of the RCS thrusters as yet, I too are using keyboard only. Excellent design very stable. Cheers for sharing your design, I\'m an absolute noob to this, but this game rocks.

[closette]

You\'re very welcome Uri G (not Uri Geller I hope - please don\'t bend my spacecraft!). If your additions or changes are useful, please share them by posting the updated .craft file below. Keep trying, and looking for tips on returning from the Mun and I\'m sure you\'ll have mission success very soon.

Yes this game rocks!

[Rickenbacker]

Nice legs, Rickenbacker! (Lander legs that is).

I tried out your new spacecraft. It\'s funny how one gets attuned to one\'s own spacecraft and fuel budget, because with yours (13 Munraker) I did not have enough fuel to make it all the way down to the Mun\'s surface, even though by comparison, my MunandBack131A has only 1 set of solids not two, and more mass in RCS tanks and fins. On yours I lit both sets of solids off as soon as possible - should I have waited until higher in the atmosphere or is there a fuel strategy I am missing?

I also had some overheating problems with your lower liquid engine stage, but just backed off the throttle a little and was OK.

May I suggest that you use 4-fold symmetry for your lander (i.e. 4 hip tanks not 3, and 4 lander legs), and add an additional RCS tank to it? That would work better. I could modify your spacecraft myself I guess, but would appreciate it if you could provide a .craft file - once you\'ve tested it out of course.

Thanks for 'exchanging' spacecraft - that\'s what this part of the forum is for!

I just used the solids to get a quick boost of the ground, but I think perhaps that your design is more efficient for achieving orbit. My rocket drags too many tanks too high, I should probably scale back the outer stacks and have them jettisonable like you did. Even though mine is more powerful, I also find it harder to get to the Mun without running out of fuel! I guess lighter is generally better, and I do tend to overbuild a bit.

It definitely needs another RCS tank. Or perhaps I should remove some of the RCS rockets, as it is the tank empties way too fast, and I don\'t really rely on the RCS to land anyway... I\'ll have to tinker a bit with that. And adding more tanks to the lander and removing some from the bottom might actually make it more efficient. The landing legs are probably going to remain, though. They\'re so heavy, I don\'t want to add another one unless I have to.

Damn, who\'d have thought you\'d learn this kind of stuff gladly, in order to play a game?

[closette]

I added 4 hip tanks and legs, and 3 more solids to your ship, and just about landed on the Mun, but something is going on with your lower stage using up all its fuel before getting close to orbit. A side-by-side comparison may be in order. Thank you for sharing your ship with everyone all the same - that\'s how we learn - and I\'m sure that mine isn\'t the most efficient either.

> Damn, who\'d have thought you\'d learn this kind of stuff gladly, in order to play a game?

D\'accord!

[Rickenbacker]

D\'accord! I added 4 hip tanks and legs, and 3 more solids to your ship, and just about landed on the Mun, but something is going on with your lower stage using up all its fuel before getting close to orbit. A side-by-side comparison may be in order. Thank you for sharing your ship with everyone all the same - that\'s how we learn - and I\'m sure that mine isn\'t the most efficient either.

Well, I\'ve been tinkering with the Moonraker for a few hours now, and finally realized that adding more stuff to it was not the solution . In the end I used a much lighter lander, on top of first a huge rocket, then an orbital insertion and munar insertion stage, and finally a braking stage for the mun landing. When I tried it just now I arrived in munar orbit with a bit of fuel left in the lunar insertion stage (the three engine one), then used the braking stage to basically stop, then fall to the surface, hover and then stage so the lander didn\'t have to use much RCS fuel to land. Didn\'t get back, though, but that\'s probably my fault for being sloppy while taking off. The basic idea with a massive lower stage and lighter upper stages seem to work, though.

I think it might be possible to put legs on the second to last stage here, so I can take off from the Mun with the remaining fuel in the current 'braking' stage. I\'ll have to experiment with that. Meanwhile, here\'s the latest iteration. Damn, it\'s fun trying to work with the stock parts .

[closette]

Downloaded your new craft and made it to the Mun (survivable crash due to my poor flying skills). Doesn\'t even need any SRBs - very nice 3-stage Mun rocket, thanks!

Hope other'stock' enthusiasts will download these and have fun with them as well!

[Rickenbacker]

It had SRBs at first, but they pulled it off course for some reason. I also don\'t know why I get a rolling moment to the right when I pitch or yaw, but that seems to happen with all my rockets.

There used to be a thread with 'stock only' creations in here, which I loved. That\'s the reason I jumped in here, and I\'m glad I did .

[Uri G]

Ha not Uri Geller but Yuri Gagarin, I misspelt his first name, I thought the pic would give it away . Anyway all I modified to your machine was to add a bit off oomph to get it off the ground with a few extra SFBs, mainly because I\'m still struggling a bit to find a good orbit to set up a mun approach & some extra RCSs for a bit of overkill & some struts to hold it all together. I\'ve tried to attach it so hopefully it works. I also read on another post that at about 10000m start to lean at about 80 degrees then all the way over between 30-40000m. I\'m finding obtaining a good orbit using this method works for me most times.

[Rickenbacker]

Ideally I guess you\'d lean over gradually at a certain, optimum altitude, so that you\'re always pointing the nose at the prograde marker on the navball. But I tend to just boost up to a certain altitude, then pitch over in steps, like you mentioned, Uri. Then there\'s the matter of throttle control, and here I really have no idea. I currently try to get to 200m/s, then maintain that until I reach around 25.000m where the air is thinner, then full throttle while I pitch over to get the most speed and altitude possible. But I don\'t know if that\'s the most efficient method.

[Uri G]

Hi Rickenbacker, yes its all a bit hit and miss at the moment, I seem to be sort of getting the hang of obtaining a solid circular orbit by absolutely gunning it full throttle from lift off pitching over gradually so fully over by 40k still accelerating up until about 2200m/s then shut off so you sneak up to the AP once there or just before, gun it again and hit the map button and watch the orbit form. I\'m finding a much more circular & stable orbit this way. The craft closette designed is heaps stable and easy to fly, I used her design and added a bit, give it a crack it certainly gets you up there.

[Rickenbacker]

Yeah, I\'ve got the orbit thing down, but I can\'t help feel that there\'s an optimal way of doing it, that would probably save lots of fuel... If only we knew what speeds to use and when to pitch over.