capi3101

Well, the maths are tricky. You have a ship with a certain initial mass (which will change as you burn fuel), a rocket with a certain maximum thrust level (i.e. the amount of force it can provide for braking) and the gravitational force of the body you're landing on (which changes with altitude). The easiest case scenario would assume gravity and your ship's mass are constant; then it'd just be a force-balance and kinematic equation problem using Newton's second law (F=ma) to determine the rate of deceleration (engine thrust minus gravitational pull). Because the mass of your ship and gravity are not constant, you also need to know the rate at which your craft is losing mass and the rate at which gravity is increasing. It becomes a third-order differential equation. Tricky stuff. Now, if you want to go through it, we can. I'll need some sample parameters for an example case.

Sent up the fourth lock to the Mere space station around Mun yesterday. While that technically finished out the station, I had decided a few days ago to go ahead and replace the first lock so that they'd all be uniform (and to balance out the mass - I plan to send the assembled station to Minmus when its Munar mission is complete), so I had Jeb dock to the port with Screwdriver 7 (the utility craft I used to send him up with some KAS parts that turned out to be unnecessary but lent itself to a cool spacewalk), undocked it and had him send it on a Munar impact trajectory. With Jeb's maintenance mission complete, I went ahead and sent him back towards Kerbin. Meantime I launched a replacement lock and got it on a course for Mun - the last piece of the station. Still need to try and figure out what's going on with the docking ports. Inquired to fixes about that yesterday on the forums; have not yet attempted to implement any fixes. While all this was going on, my latest 'tater catcher mission hit Kerbin periapsis, so I went ahead and watched it ride through to 45,000 meters in Kerbin's atmosphere. Its total orbital period is now about ten hours. I was going to go ahead and try to bring it down closer but it occurred to me that I really oughta try to make an effort to change the inclination of its orbit, which is best done at apoapsis of course (and the further away the better). I also want some practice using Claw's method for asteroid intercept and while this particular rock is definitely in a Kerbin orbit at this point I can still use the techniques discussed to bring some supply missions to the thing. All happened in rapid succession last night; I found myself having to switch back and forth between the missions one right after the other. Fun times.

Interesting design. Not sure I'd go with the huge fuel tanks (though that's a personal preference; I don't like the 8.2:1 fuel ratio of the things as compared to the 9:1 of the Rockomax and FL-series tanks). Can't really get a good look at the boosters either - is this thing an SSTO? I'm assuming the need to hold the boosters in place is why you've got all those structural panels. That's two puller designs y'all have posted up here so far - what are the advantages of pullers versus pushers when it comes to 'tater catching? Vice versa? My own design so far is a pusher, though that's more because of the way I've done things traditionally; I've had little success with pullers.

Yeah, I saw Claw's tutorial for asteroid capture outside Kerbin's SOI today; I might give that a shot next time out. Especially if I get another 'tater on a collision course.

I had actually given some thought to using the KAS winches. I just figured the mass of the rock would strain the lines a bit too much. Do you have radial connector ports on the rock or do you have grappling hooks/anchors deployed there? By "lots of fuel", about how much are we talking about, roughly? My current rock catcher utilizes a single Jumbo-64 tank with 4 nukes. Steering is a serious issue; that's really where I'd like to try to improve things the most.

Howdy all. Quick question for y'all with more than a slight degree of laziness on my part: does anybody out there have a good design that you use for catching asteroids? The bigger the better. What kind of elements do y'all usually put into your 'tater catchers anyways? Claw obviously. What else? Basically just seeing if I can make my current design any better.

Thanks Claw, I appreciate it. I'll go ahead and go through those posts to see if I can figure out what it's doing, and if not I'll stop hijacking this thread.

Hey, which one of Claw's posts has the common bugs and workarounds? I have a related issue; I've got ports on a space station that say they're docked, they definitely hooked up with one another when the docking took place but you reload it you can definitely see a visible gap between the ports even though the game says they're docked. I'm pretty sure this is an old issue but I could still use some guidance on how to fix it.

Took Jeb out for a spacewalk to put out some KAS radial port connectors on Mere like I'd intended to do yesterday. I appreciate the guy who put a full-on review of the mod on YouTube that showed how to stow everything into a single container and then just take the container along; that saved me a lot of time and probably saved Jeb a lot of jetpack fuel as well. Successful mission, and fun too. Replaced the second node lock on Mere with a new design. I'll probably go ahead and replace the initial node lock as well given that I've redesigned the things since that particular mission; balance out the mass and all that jazz. Then I've still got one more lock to go. I tell you, this week's been rough - only being able to send up a single mission per game session has been a pain. On the plus side, I've come to like the LoadOnDemand mod; it has sped up loading times considerably. Getting far enough into the year in my career save to start thinking about a Duna mission. That's IF I have time to do one before 0.25 comes out.

Had some issues with KAS last night; couldn't get it to release some radial connectors from containers I had sent up to assist in the construction of Mere. Turns out the problem was I was using KAS 0.4.5 (latest version is 0.4.8); updated and the problem went away. I did go ahead and send another lock up to Mere yesterday; got the two ends to ports to match up without issue, so I'm beginning to wonder if the KAS parts will be necessary. I'll send up another one tonight and if its docking goes well I'll get rid of number two (the one that's been giving me headaches) and consider replacing the first one (the one that, despite the game insisting it's docked, has a nice little gap between it and the connecting module. Ready to be done building that station so I can grind out the Mun. I did go ahead and install the LoadOnDemand mod with the intent of saving some of my computer's notoriously low memory for other things. Not sure whether or not I like it just yet. I'll give it another go tonight.

Didn't have a lot of time to play today. Decided given the problems I'd been having with Mere to adjust the position of the docking ports on the locks to see if that would fix the problem at all. Also, since I use KAS, I decided to add winches to the interior of the locks. I sent Jeb up with some radial port connectors to add to the station; what I figure I might do is get the lock pieces close, get a Kerbal to go EVA, grab the end piece of the winch, hook it into the connector and then use the winch to help guide the locks into place. The station is more massive than the winch, so it should be a case of the lock being pulled to the station (and not the other way around). A long shot at best; really I think I just need to do better next time I want to realign the things. KAS does let you put RCS blocks on structures...makes me wonder if I could get the spokes to steer better if I added a few in some strategic points. I'd need to know where the center of mass a loaded spoke is, though. Sounds like I need to spend some time in the VAB.

Stock fairings are possible, generally using the types of parts Starwhip listed - Sepratrons, Structural Panels and Decouplers. Most folks don't use them because in the stock game, they actually wind up having the opposite effect as what a fairing is designed to do (namely improve the aerodynamics of the rocket and protect the payload until its ready to deploy). This is because KSP's stock drag model is based on the mass of the rocket instead of its cross-section (which it would be in RL). Fairings add a hell of a lot of mass to a rocket in the stock game. This increases drag, and of course it increases the size of the booster necessary to get it into orbit. The aesthetic angle isn't enough to justify their addition, at least in my humble opinion.

Guidelines for building circular stations: http://forum.kerbalspaceprogram.com/threads/62130-Tutorial-Circular-station-building?highlight=circular+station I've got one in progress at the moment and I've been thinking about throwing up the persistence file to the community anyway because I've been having issues getting both ports to connect simultaneously to join the bits of the ring together. Here it was before the weekend: I'm pretty sure mhoram is right; the branch-and-tree structure would be respected no matter what in the persistence file. Still... EDIT: In the picture above, the "spokes" are docked to the "hub", and two "ring modules" are docked to the two spokes in front. They've been joined together by a "lock" (roughly center) that is simultaneously docked. I have no idea what this structure looks like in the persistence file...

Glad to hear it. I'll caution you that Mun is trickier to land on than Minmus as a rule, largely due to two main things - higher surface gravity and hillier terrain. Procedure is still the same, you'll just need to keep a firmer hand on the helm while you're landing. F5 before your first attempt and F9 if (*when) you botch it. Getting to Mun is easier than getting to Minmus, though. No inclination change, so aiming for it is way easier.

That's a pretty nice looking base you've got there. I can't take credit for the design of Space Station Mere, though; that has to go to Tex_NL. And speaking of which, I spent my weekend finishing the base part of the station - it now has the full compliment of eight modules, giving it a crew compliment of up to eighteen Kerbals (there's currently sixteen there; I left room for visiting crews), two lab modules and the equivalent of two orange tanks worth of fuel sitting in orbit of Mun. I still haven't decoupled the transfer stage that brought the hub module to the Mun; I'm thinking once its job of supposting the grinding of the Mun biomes is complete it might make the hop out to Minmus for the same purpose. Gets done there and I might sent it back to Kerbin... I am having problems with the locks, though (the non-spoke bits that are supposed to fit between the modules). Getting them into position has proven difficult; I don't know what I'm doing wrong but NavyFish's Docking Alignment Indicator does NOT like the craft I'm using to put them in place, the one I did get in place came un-done when I reloaded the station back up (though it still says it's docked - despite there being a visible gap) and my second lock won't dock on one side. I suspect I'm having some alignment issues with the ports and may toss the station's persistence code to the community to verify. The ships putting the locks in place look......bad. Very bad. How bad? Take a Rockomax Adapter, put a Rockomax Adapter 2 on the bottom of it, stick a TR-18A on that, then a small probe core, then a Z-100 battery, then a small RCS tank, then an FL-T400, then an X200-8 and end it with a Poodle. Then take a look at what you've created and hang your head in shame.

What Red Iron Crown said. I also highly recommend Docking Port Alignment Indicator. In case you are having problems with the rendezvous, try this: 1) Target your target. In map mode, find the little chevron marked AN (or DN). Put a maneuver node on it, and then note the number it gives you; this is how far off the plane of the target you are. Pull on one of the little purple triangles - if the number goes up, you're pulling on the wrong one. Get that number down as close to zero as you can manage. Make the burn when it comes up. Rinse and repeat until you've got it at 0.0 or NaN (NaN means "not a number", which means you're so close to the plane that the programming language is barfing - it's "better than zero" in this case, though zero is quite enough). 2) Look for the little intercept chevrons. These will tell you where exactly you and the target will be when you come closest to one another. Look at the distance it's telling you. At your next apsis, put up a maneuver node and pull either prograde or retrograde. If the number goes up, start pulling on the other -grade. Do this slowly - you will reach a point where the number will start going back up; that's fine. Make the burn. Rinse and repeat at the next apsis. CAVEAT: Don't let you periapsis go below 69,000 while you're doing this; if you de-orbit, docking will be a tad difficult. You also don't want to start trying to close the gap until the target is within a hundred kilometers or so; if it's more than that but the distance is still closing, wait a few orbits until the distance becomes a little more managable. You'll save fuel in the long run. 3) There will come a point when you won't be able to do anything more useful by going prograde and retrograde at the apses. You have two choices then - either do a radial burn at an apsis, or go prograde/retrograde at a midpoint between the apses. Pretty much the same as step number 2. Ultimately if you keep this up, you'll get an intercept less than 2.2 kilometers. That's all the closer you need to get for a rendezvous. Then comes the actual docking process. Your speedometer should switch over automatically to target mode as you approach - if it doesn't, click on it until it's up. This shows the relative velocity to the target. You want this number low (you're still travelling hundreds of meters per second, but you want to be travelling at roughly the same speed as the target and this tells you how far off you are). Mind your distance to the target. If your distance starts increasing, zero out the relative velocity (burn retrograde in target mode until it says zero), aim at the pink meatball on the nav ball (this is the direction of the target - make sure you're aimed at the meatball and not the little trifoil icon, which is the direction away from the target), and thrust forward. You want to be using RCS thrusters while docking unless you're still a good ways off - though when it comes to re-aiming at the target, you want RCS thrusters off (so it doesn't give you little annoying sideways motions). Zero out your velocity at 100 meters. At 50 meters, you want to have your target's docking port selected, and preferably you want it aimed at your craft. Easiest way to do that is to switch to the targer craft, target your ship, turn in the direction of the pink meatball, set SAS, and then go back to your ship. You'll probably need to re-target your target at that point but it should be pretty close to directly in front of you anyway. Keep up the pattern of aim-thrust-zero at regular intervals and you should make a successful docking operation. Best of luck.

1) Folks have answered this one already. For a quick and dirty 3-Kerbal with 2 landing Apollo-style mission, try http://wiki.kerbalspaceprogram.com/wiki/Tutorial:_Apollo_11 . It's a tutorial from an older version of the game, so you'll want to add a Z-4 battery to the service module and maybe a quad of OX-STAT panels. Same goes for the LEM. The Skipper is also advisable for the third stage engine, second stage is iffy. I would suggest going through all of the Real Life Missions, but they're all somewhat out of date at this point (though mainly all they need is adjustments for power requirements). There is also a challenge called Doing It Apollo Style that went on last year; don't know if folks are still doing it or not but you can get some ideas from the entries. 2) The Delta-V map tells you how much delta-V you'll need to complete certain phases of your mission (i.e. the amounts by which you'll need to change your velocity). You see, a rocket doesn't have a range; the limits to where it can go are based on how efficient its engines are and how much fuel it carries around, which is all wrapped up in a neat little mathematical formula called the Rocket Equation: delta-V = ln(M/Md)*9.8*Isp, where ln is the natural logarithm function (look for it on your calculator), M is the total mass of your rocket stage, Md is the dry mass of the rocket stage (i.e. how much it weighs when it's out of gas), and Isp is specific impulse (a measure of how efficient your engines are - look for this data on the wiki and in the VAB). 4,550 is the amount of delta-V you have to have available to have a reasonable shot of making it as far as Kerbin's orbit. A Mun mission takes around 7200-7800 depending on how good of a pilot you are; Minmus takes somewhere around 6800. 3) Kethane does that I think; you might check it out. 4) You don't need to do the circumlunar (i.e. figure-8) style transfer, no, but you can do it if you want to. Cislunar orbits (where you just go) are way easier to pull off in my experience; circumlunar gets you there quicker, which is why NASA did it that way - they had these asinine things to think about like "the human need for food, water and oxygen", unlike Kerbals...

Sent up the first locking node to Space Station Mere last night. The ring now is just short of halfway complete; seven more missions (two fuel modules, another hab and another lab, and three more locks) and the station will be finished. Docking the first lock was hairier than I expected; I'm hoping that both sides of it are still docked next time I load up the station. So thrilled that I got a good glamour shot of it; I wonder how much better it would look if I could turn up my graphics settings...... Also caught me a thousand tonnes of rock. This one's got a periapsis low enough to consider a proper capture into an orbit that's ever so slightly more suitable to exploration. I need to remember to outfit my tater catchers with more RCS and some big ASAS modules though...

Hmmm....can we see the center of mass and center of lift on your pics? I'm willing to say SAS is giving you headaches but there is another possibility: your center of lift might be too far below your center of mass. Without seeing the underside of your plane that seems highly improbable even to me, but it doesn't hurt to eliminate all possible causes. I mean, it certainly looks like you're flying stock except for maybe those tail fins. Spaceplane issues? I always like to go talk to the keptin...

Only had time for a single Mere rendezvous mission last night. Thought I was going to rip off one of the ring modules already in place but managed to finagle my way on into the dock. The module I sent up and the module I collided with are ready to be joined together. I'm not 100% sure that the docking node I've got that will join them is the right size or not; it looked like it would be in the VAB but in practice it looks like it might be too small. I guess with any luck I'll find out tonight. Got another Class E spud coming within 500,000 meters of Kerbin in another couple of days; my tater catcher is up and its orbit is aligned. Probably going to attempt a capture here in another day or two.

Short answer to your question - it depends on how far into the ascent you are. If your TWR is anywhere below 1.0 during most of the ascent, you haven't got sufficient thrust to continue accelerating; you'll hit apoapsis and start coming back down. Now, if you're well into the ascent - say above 50,000 or so and already going about 2000 m/s, you might get away with a TWR that low. A low TWR also works when it comes time for your circularization burn, though by then you're not worried so much about getting up there as you are about staying up there.

To show your album, try [ imgur ]ZJNcU[ /imgur ]. You'll need to take the spaces out from between the brackets. Nice looking initial Mun base, BTW.

In general, an ideal ascent profile is one that A) maintains a even balance between the force of gravity and the force of drag acting on the rocket (i.e. a 100% atmospheric efficiency - a stat KER shows on the SFC data tab) at all times and minimizes the amount of fuel you need for your final orbital insertion burn. Alshain's got the particulars for you, though I generally find that the 100% atmospheric efficiency part is achieved when the TWR is in the 2.2 to 2.3 range; at 1.5 the efficiency is inevitably less than 100%, meaning delta-V losses to gravity. I also try to keep the Apoapsis around 45 seconds ahead past 10,000 meters myself, and I generally don't turn from straight up until I'm at that level (due to how Kerbin's atmosphere works - folks regularly call it "pea soup" down in the troposphere). To pull off an ideal ascent profile takes a steady hand and a lot of practice. Or Mechjeb - I don't use Mechjeb myself but there is definitely something to be said for how it handles launches, and I'd recommend hitting up YouTube for videos of Mechjeb-guided launches. EDIT: Shinobi'd. And for the record, I use neither NEAR nor FAR.

Put the final spoke into place for Space Station Mere in Munar orbit and sent up/docked a fuel canister (that took two tries; the initial design didn't have sufficient delta-V to make it into Munar orbit, to say nothing about rendezvous operations). At this point the station is fully capable of fulfilling its primary task: supporting multiple excursions to the surface. I plan to send up five more modules to dock at the spokes along the ring, and then I get to start sending up nodes to link the ring segments together.

I should probably let Pecan answer this, and I'm wagering I'll get ninja'd on it, but... 1) Calculate the total thrust your booster outputs. Divide that result by 11.76 (9.8, Kerbin's Gravity, times 1.2, the generally accepted minimum TWR you can have and still expect to get into orbit). The result there is the maximum cap on your rocket's mass. 2) Work the Rocket Equation backwards for the atmospheric Isp of your rocket, setting delta-V to 4500. Plug the maximum cap in as M and solve the equation for Md 3) Subtract the mass of your engines, decouplers and anything else that ain't payload or fuel tanks from Md. Whatever is left is your maximum possible payload for the design. Practical example: You've got a single stage booster with a KS-25x4 booster which you're separating from the payload with a TR-18A, with a set of four AV-R8s for additional control during the early part of the flight (for 0.13 tonnes "other" mass). The mass of the engine is 9.75 tonnes and its ground Isp is 320, and it outputs 3200 kN of thrust: 1) 3200 / 11.76 = 272.108 tonnes. 2) delta-V = ln(M/Md) * 9.8 * Isp, 4500 = ln(M/Md) * 9.8 * 320, M/Md = e^((4500/9.8)/320) = 4.1994, M/4.1994 = Md, Md = 64.796 tonnes 3) 64.796 - 9.75 - 0.13 = 54.917 tonnes. So, the maximum payload for that particular booster is 54.917 tonnes. I can work through another example if you'd like, or you could wait for more help from Pecan. Or both. Didn't get ninja'd... EDIT: Actually, I have that wrong. You have a 207 tonnes tonne difference between the maximum mass and the dry mass, so that's 207 tonnes of fuel needed. That'd correlate to six Jumbo-64s and an X200-32 worth (roughly), which have a dry mass of 26 tonnes when combined. Subtract that from the calculated dry mass there (54.917 tonnes), and it comes down to 28.917 tonnes. So that'd be the payload mass for the booster (and no, the situation is NOT improved with the bigger fuel tanks, but rather the opposite; the new extra large tanks have an inferior mass-to-dry mass ratio as compared to the traditional tanks in the game).