I am full of grief and coffee

[Markus Reese]

Welcome aboard! As for what there is, plenty more coming! The excitement is just getting started!

[technicalfool]

Much appreciated. Sorry, I see now that was explained prior. I am lacking a severe level of attention to detail. I self diagnose this as a coffee deficiency which I will immediately remedy.

Ok! Time to use what I know. I figure I'll try a three stager.

Third stage will be a "lander" for the Mun. I will aim for 1.2 TWR.

Second stage will be the orbital arrangement system. I will aim for 1.8 TWR.

First stage will be the liftoff system. I will aim for 2.5 TWR.

Thoughts? Am I in the ballpark, or am I still rooting around in the trash cans in the parking lot for discarded sandwich crusts and snack-pak leavings?

I'll say that once you're in orbit, you don't need a TWR of >1 (though it's nice to have if you're impatient). Nuclear engines for the win.

[AmpsterMan]

Whackjob, though you might not need to be this detailed yet, one thing that I have found helpful is to make sure I only use two stages for orbit. My key guidelines are to make sure my first stage nets me anywhere from 3000-3500 Delta-V m/s. Using the standard mechjeb ascent, that is enough to get your rocket horizontal before first stage separation. From there I might use a LV-909 most of the time to get to orbit. Just my $0.02

[Whackjob]

Progress so far: Whole rocket built. Three stages per the specs I listed prior. First stage got me up to the 10km mark with little trouble, and the second stage was enough to get me both exoatmospheric and into orbit. I have fuel left over and I'm going to try to burn into munar orbit with it.

#EDIT: Screwed up on landing again. I misjudged the surface, slowed down way too early, burned up all my fuel. Landed, broke my rocket, wasn't going anywhere.

Edited June 21, 2013 by Whackjob

[Bunsen]

The difference between actual distance above the ground and indicated altitude is always so much fun during landing. Try the in-cockpit view; there's a radar altimeter in there that tells you how far above the hard stuff you are (but it only gives readings once that's less than 3000 m). The 2-Kerbal lander can has very spartan instrumentation, but that radar altimeter, nav ball, and vertical speed indicator are enough if you practice a bit and aren't too picky about exactly where you set down.

[Spatzimaus]

Am I in the ballpark, or am I still rooting around in the trash cans in the parking lot for discarded sandwich crusts and snack-pak leavings?

Overkill, but not too badly. Here's why.

The bottom stage's TWR of 2.5 means that at low altitudes you'll be accelerating a bit faster than the terminal velocity increases, which means you'll want to throttle down just to avoid wasting too much energy fighting drag. If you're constantly throttled down, there's not much point in having the extra engine power. You really only need a 2.1-2.2 for any stage that's intending to accelerate vertically. Once you get up out of the thick part of the atmosphere, drag stops being an issue and you can accelerate as quickly as your ship can handle. A 2.5 isn't terribly overpowered, but it means you can throw on a slightly bigger fuel tank (lowering the TWR a bit) and get quite a bit further up before the stage burns out. Alternately, you can make the upper stages a bit heavier, like replacing regular engines with nuclear ones.

But once you're in a circular orbit, where there's no danger of crashing back down, thrust becomes almost irrelevant. EFFICIENCY is what matters there, as measured by the ISP of your engines; an LV-N, with a vacuum ISP of 800, will use half as much fuel to get the same effect as an engine with an ISP of 400; it might take much longer to accelerate, because of the lower thrust, but it'll get you twice as far on the same load of fuel (oversimplifying, of course). A TWR of over 1.0 or higher is just overkill; the main reason to want much thrust at that stage is to avoid the boredom of half-hour burn times, or when you're trying to do something with a very narrow window (like entering Gilly's SOI) where you just can't do a long burn at all. But for most situations, a far lower thrust works just fine.

And then there's your Mun stage. Mun has only 17% of Kerbin's gravity (almost identical to our own moon), which means even a TWR of 0.2 will accelerate you upwards, albeit very slowly. Granted, with no atmosphere there's less reason no to go much higher, but it still means you're lifting more engine weight than you actually need if you've got a TWR of 1.2; you could easily back that off to a 0.8 or so, use the weight savings to add more fuel, and get a higher effective delta-V. But the higher thrust gives you a bit more room for error on the landing, which might be good for you in light of...

I misjudged the surface, slowed down way too early, burned up all my fuel.

The Flight Engineer mod is really helpful for this, as it includes two separate altitude readouts, a "pressure altitude" (i.e., what the game gives you right now, a distance above the "sea level" for that planet) as well as a "radar altitude" (altitude above the actual surface below you). Having both available simultaneously makes it much, much easier to judge a descent, and frankly it's something the game should have gone with from the start, as the only times you really care about the distance above sea level is when you're flying a spaceplane or trying to aerobrake. This wouldn't be so bad if KSP didn't have such strange definitions of "sea level" on some moons (Gilly being a good example). Yes, you can use the in-cockpit view to see the altimeter, but I don't LIKE the cockpit views much and it's just a bit too limiting in general.

The other option, if you dislike mods, is to just add some spotlights to the bottom of your ship and turn them on during the descent. The moment you see the ground light up at all, jam the throttles, and use the compactness of the illuminated area to judge your altitude. (This is basically how I did my first Duna landing.) You'll still need to slow down a bit first, depending on how much engine power your lander has, but it makes it does help, depending on the time of day and color of the terrain. (Protip: do not try landing in one of the black craters on Ike at night. No amount of lighting will illuminate those.)

[Nao]

Progress so far: Whole rocket built. Three stages per the specs I listed prior. First stage got me up to the 10km mark with little trouble, and the second stage was enough to get me both exoatmospheric and into orbit. I have fuel left over and I'm going to try to burn into munar orbit with it.

#EDIT: Screwed up on landing again. I misjudged the surface, slowed down way too early, burned up all my fuel. Landed, broke my rocket, wasn't going anywhere.

1)Recreate using actual jet engines and RCS

2)fly around pretending to control the thing

3)acquire fun and skills

4)crash and burn!

Or just test the actual Mun lander with more powerful engine on launchpad and learn to land without braking things.

The 1,2 Mun TWR is ok from efficiency standpoint but it is quite unforgiving. Try using something with more thrust (up to 1,2 Kerbin TWR), for example a Poddle engine, so you won't have to be careful and just suicide burn when you can see Mun rocks look at you funny.

[Spyritdragon]

Progress so far: Whole rocket built. Three stages per the specs I listed prior. First stage got me up to the 10km mark with little trouble, and the second stage was enough to get me both exoatmospheric and into orbit. I have fuel left over and I'm going to try to burn into munar orbit with it.

#EDIT: Screwed up on landing again. I misjudged the surface, slowed down way too early, burned up all my fuel. Landed, broke my rocket, wasn't going anywhere.

MOAR BOOSTERS!

And while landing, you can use your shadow. The highest point on the mun is at 3340m, so you can safely fall untill there. When you think you're close to the ground, you can use your shadow to confirm that - when you're actually getting close to the ground, your shadow will be clearly visible on the munar surface, assuming you're landing on the bright side. If not, i suppose you could bring an illuminator :-).

[el_coyoto]

MOAR BOOSTERS!

And while landing, you can use your shadow. The highest point on the mun is at 3340m, so you can safely fall untill there. When you think you're close to the ground, you can use your shadow to confirm that - when you're actually getting close to the ground, your shadow will be clearly visible on the munar surface, assuming you're landing on the bright side. If not, i suppose you could bring an illuminator :-).

Yup, I usually use two Illuminator mk1 (the spotlights) pointed towards the ground and collimate them so that the lights they project on the ground overlap only when very close to the ground... It requires some trial&error to set-up the spotlights and get used to the visual feedback they provide, but that's a nice trick to help landings while keeping your lander stock.

Keep up the good work Whackjob!

[Whackjob]

I think I might want to create a fuel depot. One in Kerbin orbit, the other in Munar orbit. I like the idea of having "Breathing Room". So now the fun part will be figuring out a plausible design I can get in orbit. Getting one to the Mun shouldn't be too tough. I figure I can always dock a "pusher" and shove it out there.

[Spyritdragon]

Use your Earth one to refuel your Munbound one ;-).

And actually, a fuel depot need not be more than a tank of fuel, a docking port and a probe core with a small solar panel and a battery. If you can get a full jumbo-64 into Munar orbit, you'll be able to fully refuel many of the reasonably-sized Munar landers. That'd refill 15 of my first munar landers :-).

[Whackjob]

I've got fuel-tank-lifter I euphamistically call the "Addled Sow Mk1". So far... it'll get a tank exoatmospheric, but either I'm bad or it's not working out for me. Gotta tweak it...

What's a good altitude for a fuel depot? I don't wanna have to readjust its orbit all the time... boosting it and such. So about 100,000 meters?

#EDIT: Scrapping the Mk1. Getting me very close, but the tweaks have quickly gotten out of hand and greatly overcomplicated the build. Time to try something else.

#EDIT2: Got an alternate version going. Initially used a nuclear engine for orbital placement. Not enough power. Changing that out for a poodle.

#EDIT3: It occurs to me that I have a problem. If I drop the final engine when I've got the tank and docking assembly in the proper orbit, that tank will follow along merrily. I don't want to full the skies with discarded tanks. Especially near my fuel depot. Is there any way to detach the tank, yet remain control of the positioning thruster assembly? Two control cores, perhaps?

Edited June 21, 2013 by Whackjob

[Bunsen]

I like 100-110 km for stations in Kerbin orbit. Not too hard to get there, but there's enough room below it that you can hang out in a 70 or 80km orbit and catch up if you launch too late.

If it's structurally simple, then I'll put an ASAS module on it and point it due north or due south. It makes aligning the approaching ship for docking really easy; no fiddling around trying to see where the depot is pointing and match it, just point to 0 or 180 on the nav ball. Don't forget the solar panels or an RTG for that probe core, 'cuz the ASAS quits if the probe's battery dies. You eventually will forget those; this is just guaranteeing an "I told ya so!" moment for later.

[AmpsterMan]

Totally loving your crazy schemes to getting to Mun. Can't wait to see what you'll try when going for the planets

[Spyritdragon]

I've got fuel-tank-lifter I euphamistically call the "Addled Sow Mk1". So far... it'll get a tank exoatmospheric, but either I'm bad or it's not working out for me. Gotta tweak it...

What's a good altitude for a fuel depot? I don't wanna have to readjust its orbit all the time... boosting it and such. So about 100,000 meters?

#EDIT: Scrapping the Mk1. Getting me very close, but the tweaks have quickly gotten out of hand and greatly overcomplicated the build. Time to try something else.

#EDIT2: Got an alternate version going. Initially used a nuclear engine for orbital placement. Not enough power. Changing that out for a poodle.

Is this your Mun depot or your Kerbin depot?

For a Kerbin sattelite, i've found orbital rendezvous more challenging when the object im RV-ing with is at about 100 km and im behind it (i don't have very much experience). I don't like orbiting too close to Kerbin, so i personally prefer orbiting my station at 120-150 km above Kerbin. This makes that i need less loops around Kerbin to catch up to my object, since timed launching is a subject i haven't really got mastered yet, and i regularly end up with phase differences that are 90 degrees or more.

[Spatzimaus]

What's a good altitude for a fuel depot? I don't wanna have to readjust its orbit all the time... boosting it and such. So about 100,000 meters?

There's no readjusting necessary in this game. Above 69078m, there's no atmosphere at all, so orbits will stay perfectly stable... except that when you're controlling some other vessel, the game doesn't use quite as accurate a simulation for all other vessels in the game. This can cause orbits to wobble a bit, which might take your depot below 69km if you were to put it at 70-75. Now, the game also doesn't model friction for any vessels other than the active one; if your depot WERE to drift below 69km while you were controlling your lander, it wouldn't start to spiral in from friction. Instead, the game hard-kills any other vessel that goes below about 25km altitude, but that's not likely to be an issue. But you don't want your depot to drift below the 69km line, because anything trying to dock with it WOULD feel drag (making it pretty much impossible to link up), as would the depot if you were to switch back to it. So the absolute minimum altitude I'd use is around 80km.

You want to be as low as possible to leverage the Oberth Effect, but you also want to be high enough that a vessel trying to dock with your depot doesn't accidentally skim the atmosphere. My first fuel station was at 90-100km because of this. The idea would be that a vessel would take off, circularize in a low orbit and dock with the depot, refuel, and then easily travel out of the Kerbin SOI. Putting the station much higher reduces this effect, which costs you fuel in the long run.

But there's one other consideration: time acceleration. Below 120km, you're limited to x50 time acceleration, but above 120km you can also use 100x. Above 240, you can use 1000x. Time acceleration is really useful for getting orbits to line up right for docking, so being limited to x50 is a bit rough for something you'll want to use often. Because of this, I put my main fuel station at about 125km. (I've also got one at 200 and one at 314, for other reasons.)

#EDIT2: Got an alternate version going. Initially used a nuclear engine for orbital placement. Not enough power. Changing that out for a poodle.

Yes, the nukes are weak on power, which is why you use several of them, especially on 2.5m tanks. (I prefer to attach four of them to the sides, instead of using splitters on the bottom, but YMMV.) As I said before, once you reach orbit what you care about most is efficiency; that poodle will take more than twice as much fuel to make the same orbital changes, and that makes a BIG difference if you're trying to get a depot to one of the other planets or something. As long as you've got an ASAS on your tanker, you can just set it to the right heading and go watch TV for a few minutes while it burns. You COULD turn on physics acceleration, to go up to x4, but that can cause your designs to rip themselves apart so I'd avoid it.

That being said, my own 450-ton tanker (capacity is about 12 orange tanks) has an inefficient, powerful engine for major orbital changes, and only uses high-efficiency engines (hybrid ions from a mod, efficiencies and thrusts comparable to the nukes) for minor tweaks. At that weight it'd take hours to complete a burn to Jool if I were to use nukes, so it's just not an option. But if you're making a small depot, say 1 orange, then a cluster of nukes would work just fine.

[el_coyoto]

I've got fuel-tank-lifter I euphamistically call the "Addled Sow Mk1". So far... it'll get a tank exoatmospheric, but either I'm bad or it's not working out for me. Gotta tweak it...

What's a good altitude for a fuel depot? I don't wanna have to readjust its orbit all the time... boosting it and such. So about 100,000 meters?

#EDIT: Scrapping the Mk1. Getting me very close, but the tweaks have quickly gotten out of hand and greatly overcomplicated the build. Time to try something else.

#EDIT2: Got an alternate version going. Initially used a nuclear engine for orbital placement. Not enough power. Changing that out for a poodle.

#EDIT3: It occurs to me that I have a problem. If I drop the final engine when I've got the tank and docking assembly in the proper orbit, that tank will follow along merrily. I don't want to full the skies with discarded tanks. Especially near my fuel depot. Is there any way to detach the tank, yet remain control of the positioning thruster assembly? Two control cores, perhaps?

100 km seems like a good altitude for a fuel depot :

• you don't want it to high to avoid wasting too much fuel reaching it or losing the Oberth effect if you plan your injection burn right after you undock (usually the purpose of a fuel depot)
  
• you don't want it too low to leave yourself some room to maneuver and reach your depot safely without scraping the atmosphere or waiting for hours for a Hohman window because your destination and target orbits are too close.
  

Concerning your debris problem, yes, you can stick a small unmanned probe and use the Mission Center to terminate it (remote controlled explosions FTW!). Or plan to leave some fuel and use it to de-orbit it cleanly.

Just remember to provide it some electricity with a solar panel or a RTG. Or a battery large enough to suit your needs...

Also, I learned a new word today : "Addled"...

EDIT : just like Spatzimaus said above. And taking into account the max time acceleration IS a smart thing to do.

Edited June 21, 2013 by el_coyoto

[Whackjob]

Oh, man. Here I am at the office, and I've got all kinds of mad ideas. I can't wait to get home to try them out. In example, I think I'm going to actually land a fuel depot right on the Mun. For refueling operations, I think it'd be interesting to have an electrically driven fuel tank with wheels and docking ports on both ends. Drive to the tank stack, top off, drive on over to the nearby lander, fuel it up. Don't even have to land right next to it.

Mun Fuel Depot Alpha. For the finest in Kerbalian fuel shutting service.

Side question: When you go EVA, how do you jetpack around?

[TomcatMVD]

Oh, man. Here I am at the office, and I've got all kinds of mad ideas. I can't wait to get home to try them out. In example, I think I'm going to actually land a fuel depot right on the Mun. For refueling operations, I think it'd be interesting to have an electrically driven fuel tank with wheels and docking ports on both ends. Drive to the tank stack, top off, drive on over to the nearby lander, fuel it up. Don't even have to land right next to it.

Mun Fuel Depot Alpha. For the finest in Kerbalian fuel shutting service.

Side question: When you go EVA, how do you jetpack around?

Hit "R" to activate it just like with your thrusters.

[Whackjob]

Gotcha. Ok, so I've got some plans thought up for a Munar fuel rover. Obviously, mass is going to be an issue, so I don't think I'll use those large orange tanks to drive fuel around. I think maybe I'll use the large tanks available in the demo. One or two of those, some cross bracing, six wheels, a battery or two, solar panels, maybe positioning thrusters to help with bumps or getting stuck on rocks, and a docking port on the nose for passing fuel.

I think as far as the fuel depot goes, I can just land a single orange canister with batteries on both ends, solar panels across the top, legs, and a docking port. Fuel the tanks and charge the batteries at the same time for the fuel shuttle.

Next noobie question: Fuel lines. Do they work a certain way? I mean, do they just balance the fuel level between the tanks they are attached to, or do they actively pump fuel from one bottle to another? Is that determined by the order at which you place each end of the connection? Or is there a differing logic to it?

#EDIT: Never mind. Of course there's a wiki. Looking it up myself

#EDIT2: Ok, so they do pump from one side to another. I though it just "equalized" the fuel between two tanks. Now I see why many of my tank linking schemes have failed.

#EDIT3: Ooooooh! Now I can build something where the engines are higher up and the tanks can be dropped from the bottom. Like a flying bloody scaffold! I see many odd and large orbital constructions in my future >

Edited July 22, 2013 by Aphox
Merged multiposts

[Spatzimaus]

Gotcha. Ok, so I've got some plans thought up for a Munar fuel rover. Obviously, mass is going to be an issue, so I don't think I'll use those large orange tanks to drive fuel around.

That's just a matter of scale. There are some big wheels available, and they only require electricity so there's not much problem scaling up a design. Here's my own Mun fuel refinery rover, Mun Unit Zappa:

It uses a bunch of mods, most notably Kethane, FusTek, KAS, KW Rocketry, BOMP, Robotic Arms, and HOME. I landed it by attaching a few vertical engines to the "wing" ports, which are perfectly lined up with the center of mass. It's shown drilling/refining; some bits, like the bottom solar panels, fold up when I retract the drills, and if I land one somewhere with an atmosphere I need to fold up pretty much everything when moving.

#EDIT2: Ok, so they do pump from one side to another. I though it just "equalized" the fuel between two tanks. Now I see why many of my tank linking schemes have failed.

Not only do they only go one direction (denoted by the arrows), they don't actually "pump" fuel. What happens is that an engine prefers to draw fuel from any tanks connected through fuel lines before drawing fuel from its adjacent tank. So, if I use manual fuel transfer (alt-clicking) to make tanks A and B both be half-full, and there's a fuel line from B to the A, and an engine on A, it won't automatically move the fuel to make A be full and B empty; instead, the engine on A will just empty the half-tank furthest from it ( before emptying the closer one (A). If both A and B have engines, then B will run out of fuel VERY quickly, since both engines will draw from it, at which point only engine A will be burning as it finishes off the half-tank it's attached to.

#EDIT3: Ooooooh! Now I can build something where the engines are higher up and the tanks can be dropped from the bottom.

It's been done. Just mind the separation debris; uncontrolled debris inside your rocket's structure has a nasty tendency to break things. It doesn't take much of a collision to cause an engine to break off its fuel tank, and in an atmosphere you'll have a hard time controlling the tumbling of any detaching parts.

Also, note that empty fuel tanks don't weigh much; only 1/9th of a fuel tank's filled weight is the tank itself, the other 8/9ths are the fuel. Once a stage empties most of its weight is in the engines, not the fuel tanks, so you won't gain much by ditching fuel pods as you go.

[Whackjob]

It's been done. Just mind the separation debris; uncontrolled debris inside your rocket's structure has a nasty tendency to break things. It doesn't take much of a collision to cause an engine to break off its fuel tank, and in an atmosphere you'll have a hard time controlling the tumbling of any detaching parts.

Also, note that empty fuel tanks don't weigh much; only 1/9th of a fuel tank's filled weight is the tank itself, the other 8/9ths are the fuel. Once a stage empties most of its weight is in the engines, not the fuel tanks, so you won't gain much by ditching fuel pods as you go.

Oh, I dont' doubt it's been done before. A game out this long, and with me coming in to the foray late, I doubt I'll be breaking any really new grounds. Though I might do it with my own kind of weird flair.

I do have a question I cannot resolve via the wiki, though. Are there any kind of hinge and mechanical actuator? When I get home tonight, I might want to put something together that can... unfold... for lack of a better term.

[Bunsen]

Here's my own Mun fuel refinery rover, Mun Unit Zappa

Hah! I truly loled.

I do have a question I cannot resolve via the wiki, though. Are there any kind of hinge and mechanical actuator? When I get home tonight, I might want to put something together that can... unfold... for lack of a better term.

Not in stock parts, except for the lander legs and solar panels that you can't attach things to. There are some mod part packs for robotics. I haven't messed with them yet or I'd recommend one. If you're crazy enough and want to stay strictly stock, you might be able to rig something with sorta-interlocking girder structures as hinges and release it with decouplers. It will probably explode. I want pictures if you try it.

[Whackjob]

Not in stock parts, except for the lander legs and solar panels that you can't attach things to. There are some mod part packs for robotics. I haven't messed with them yet or I'd recommend one. If you're crazy enough and want to stay strictly stock, you might be able to rig something with sorta-interlocking girder structures as hinges and release it with decouplers. It will probably explode. I want pictures if you try it.

Hehe. I might just put together a pintle and a gudgeon with random parts, and then use those little thrusters to open and close the hinge. It'd be ugly, there'd be friction, and the physics engine would probably outright rebel, but it might be fun to try.

[Spatzimaus]

A game out this long, and with me coming in to the foray late, I doubt I'll be breaking any really new grounds.

I didn't mean you shouldn't try. Just that if you get stuck, or if you just want some ideas, you can search through the forum to see pictures/descriptions of previous attempts at the concept. Granted, with the fairly recent forum semi-wipe a LOT of good information was lost, but you could still probably find something.

Are there any kind of hinge and mechanical actuator?

Not in stock, but look for the Damned Robotics mod. It adds some hinges and rotating servos. Some folks have used those to make VTOL designs, or giant robots. You can't get TOO complex, though; if your folding causes anything to collide/overlap, chances are the whole thing will explode.

Now, that's for powered rotation, where you have total control over the angles involved. People had previously made unpowered hinges using docking ports, with the magnetic restoration force set extremely low, or with long chains of girders/struts. So there are stock ways to do certain things.