Jason Patterson

Is it safe to assume you know about launch windows and the like? http://ksp.olex.biz/ gives reasonably good ejection and phase angles for making interplanetary burns. It's definitely cheapest to make your burn from LKO. It ought to be possible to set up a gravity assist past the Mun that gets you there, but getting the launch window right so that the minimal amount of delta-v gained from your Mun flyby actually helps you is tough. A gravity assist from another planet is also possible, but those kinds of things almost never happen to line up right and you wind up wasting more fuel getting there in the long run.

Yes, g0 is a conversion factor, it doesn't matter where you do the math, it will always be Earth's surface gravity. (Aliens wouldn't have chosen the second as the unit of the answer, so they'd have a different constant in its place.) If by efficient you mean 'least fuel used' then yes, any grouping of engines with a higher average Isp will always use less fuel than any grouping of engines with a lower average Isp for a given amount of thrust. If this is an orbiter though, thrust is pretty far down in the list of features to be considered. Fuel mass, non-fuel mass, Isp, and thereby overall delta-v are far more important once a minimal amount of thrust is available.

Pol is very very low mass, so just about any propulsion system can give you a safe landing. Are you comfortable with less ambitious navigation? ex: Could you get to Eve or Duna without spending huge amounts of fuel? Minmus? Can you do a rendezvous/docking? Ideally you want to make a Kerbin --> Jool transfer with a periapsis at roughly the altitude of Pol's orbit. This is a case where aerobraking is not the best option because maneuvering in Jool's gravity well is fairly expensive. Once you've reached your Jool periapsis, burn until you are just captured by the planet and adjust your orbit's inclination at the highest altitude (slowest speed) orbital node you've got. If the orbital nodes are at high velocity points of the orbit and off by a significant amount, it might be cheaper to make a massive adjustment at apoapsis and bring one of the nodes out to a higher altitude, lower speed point in the orbit where it can be corrected more easily. As for the ship, there's not much to it. If you're going with a 1 kerbal vessel, you can use the Mk1 command module, an ASAS, an X200-32 fuel tank, and one LV-N engine. Use the long trusses to extend your landing gear past the nozzle of the LV-N and you're set. The ship as described has nearly 10 km/s of delta-v and masses roughly 20 tons. If you can get that into orbit as is, it is more than capable of getting you to Pol and landing (~2km/s to get to Jool, ~2km/s to be captured at Jool, ~2km/s to rendezvous with Pol, ~200 m/s to land.) Ideally you would want to save as much fuel as possible for the trip for the inevitable deviations from the ideal, but if you need to use part of the delta-v to get to LKO you could also add a docking port and refuel before departing for Jool.

I feel like avionics is a lot closer to ASAS in this version... Maybe I've only built unwieldy planes since the update; the parts are identical. It's odd how your mind wants to find differences in a case like this, even though usually there are none.

You could also accidentally be setting the trim on your ships, particularly if you tend to use physics warp. If you hold the alt key down a bit too long while controlling the vessel, the trim will wind up being non-zero and weird things can happen.

Sorry it wasn't better news. You should make your son aware now that because the game is still being developed heavily (it's in alpha 0.20 right now), he is likely to lose everything at least one or two more times before the full game is actually released. It hurts a lot more when you've got 100 missions going and have spent a disturbingly long time getting things to the state that they're in. It's not a reason to quit playing the game, or to avoid trying ambitious missions, but it's good to keep in mind that the things we're doing now are likely not going to last.

The command module - ASAS connection is extremely weak, if you're using that. Just about any strong jolt will break them apart. I actually use it as a defacto decoupler for my final landing parachutes sometimes. You can either add struts between the command module and whatever it is connected to (and perhaps from that to the fuel tanks) or simply attach the parachutes to the fuel tanks directly.

I don't know about a particular mod, but it's fairly easy to open your game folder and make a copy of your quicksave occasionally as you play, if you're wanting to preserve a range of game states.

Because of the way that parts are referenced in the file, deleting any given part (except the very last one in a vessel) causes all of the others to get out of order. If the part isn't causing problems, it's best to leave it in place. If it is causing problems and is surface mounted, you can insert a small part in its place (like a strut.) Here, unfortunately, it looks like you have several parts that you want to get rid of (a symmetry 4 group.) There's no easy way to do that, and persistence editing isn't really worth the time. You can put the portion of the vessel that is in orbit on the launch pad without the problem part in place, then quicksave. Find the vessel on the launchpad and copy its part listing in place of your existing ship. It's pretty straightforward, but be sure to back up your persistence file before messing with it in any way.

Depending on the body you're orbiting, it might be simplest just to burn normal to your velocity until you've made the adjustment you want. As your velocity changes direction, so does its normal, so you have to continuously change your ship's orientation. For a high velocity orbit it's going to take a fair amount of delta-v to do this though. If you're on Kerbin, you're best off just launching the vessel anew and burning toward the north or south to begin with. Make your usual gravity turn, but instead of turning toward 90, turn toward 0 or 180. Depending on how particular you're feeling regarding your polar orbit you can burn slightly to the west to correct for the eastward velocity you begin with from Kerbin's rotation. In general, if you're in a circular orbit then the minimum delta-v is given by: delta-v = 2v sin(theta/2) where v is the orbital speed and theta is the inclination change. Here that would be 90 degrees, so you're looking at 1.4 times the orbital speed to change from an eastward orbit to a north- or southward orbit. That's the ideal, not what I suggested above. If you're set on altering an existing orbit, burn to change your orbit (which will probably wind up being eccentric) then fix the eccentricity.

You can get a prepaid debit card from Walmart or similar and use that via Paypal. I don't know about your particular situation, but if you're young, you can likely convince the parents to pay $20 or so in order to let you spend hours playing a game that teaches you all about physics and orbital mechanics. I'm a physics teacher, and honestly, this game is just great for gaining an intuitive understanding of things like gravity, momentum, forces, and the like. Also things explode. Odds are good that at least one of your parents spent a not insignificant piece of their childhood dreaming of being an astronaut too, which won't hurt. Get your dad or mom (whichever hasn't been turned into a hollow shell of a person in the decades since their childhood) to fly a rocket. They'll buy it for you. If you're not young, well, the Walmart debit card option is probably the easiest. Also, congrats on that whole not-having-been-turned-into-a-hollow-shell-of-a-person thing. Best of luck. Let us know how your Mun landing goes. Success or crater, both make good stories.

Getting to the Mun and back efficiently: We'll assume that you want to go Kerbin Surface --> LKO --> LMO --> Mun Surface --> LMO --> Kerbin Surface. Each one of these arrows has an optimal flight plan (and a whole ton of suboptimal plans.) I am just going to give you my basic way to get through the trip in one piece without overspending on fuel by too much. There are some places that you can shave a bit more delta-v, but I wouldn't worry about optimizing the mission until you're more experienced in doing the planning and building that gets you there in the first place. Kerbin Surface --> Low Kerbin Orbit Low Kerbin Orbit is any orbit that is near the upper limit of Kerbin's atmosphere, or roughly 70-100km. The lower the orbit you can get into, the more efficient your flight will be, but at the same time, you've got to make sure you get clear of the atmosphere. 1. Turn on ASAS (T key) and throttle up all the way (left Shift.) The throttle won't do anything until later in the flight, but having it preset won't hurt anything either. Switch to map view (M key) and press the keypad . button to bring up the navball, then toggle the map back off to switch back to the vessel (M). 2. Press space to engage your first stage, the solid boosters and the launch clamps. The solid boosters can't be throttled or turned off, so just watch the ship go up while they burn. This is a good time to find the 90 degree direction on the navball (east.) It ought to be on the right side. 3. When the solid boosters burn out, press space to engage the second stage, dropping the solid boosters and lighting the liquid. You will want to throttle back a bit (left control) shortly after turning on the liquid boosters; they are somewhat overpowered for this job. Ascending too quickly wastes fuel fighting air resistance, and ascending too slowly wastes fuel by fighting against gravity. A slightly suboptimal, but easy to remember strategy for managing your speed is to try to keep it at around 100 + 10 for each kilometer of altitude. So at 1km you'd want to be going 110 m/s, at 2km 120 m/s, and at 10km, 200m/s. This is a bit slow, but it's easy to keep track of. Closer to the ideal would be to hit about 250m/s by the time you get to 10km. 4. When you reach 10km, turn off ASAS (T) and begin turning toward 90 degrees. The beginning of the turn can be done fairly rapidly - you want to get to a 45 degree pitch pretty much as fast as this rocket will let you turn (drag will keep you from yawing as fast as you might like.) Once you're at least to 45 degrees, engage ASAS (T) and switch to map view (M). Zoom in to get a better view of your vessel's orbit (scroll up). Ideally you want to keep your apoapsis 20-40 seconds ahead of your ship as you ascend. It will eventually get away from you, but while you're able to control it, that is a reasonable time limit. The way that you control the distance that your apoapsis is ahead of your vessel is by pitching up or down (always staying on the 90 degree, east, line.) If you pitch down you will decrease vertical thrust and so you will get closer to apoapsis. If you pitch up you will increase your vertical thrust and so your apoapsis will get farther away. At near orbital speeds simply going forward will also push the apoapsis away from you, which is to be expected. Never pitch below horizontal unless you have a good reason to do so; you'd be countering the effort you've made to get going up in the first place if you did. You can also increase your throttle to the maximum once you're above 15km or so. 5. Since we're shooting for LKO, if your apoapsis gets above 85km or so, turn off the engines (X key cuts the throttle.) 6. Coast to just before the apoapsis and then burn at 90 degrees with 0 pitch until your orbit's periapsis is above the atmosphere (70km+). You can circularize if you like, but it really doesn't matter. If you're flying the Kerbal 5 (or my Kerbal 5. then you will run out of fuel before you reach orbit. You'll know this happens when you lose power (yeah, duh, I know.) Toggle the map off (M) and drop the liquid booster stage. This will also ignite the LV-909 engine and let you finish getting to orbit. LKO --> LMO Unlike LKO, the only lower limit for Munar orbit is the surface of the planet itself. In this process you want to get the lowest Munar periapsis possible (we'll shoot for 5km) while spending the least amount of fuel possible. 1. Set up a maneuver node roughly 90 degrees away from the Mun's current position (if the Mun is at 12 o'clock, put your maneuver node at 3 o'clock, not 9.) (Left click on your orbit in Map View and choose Add Maneuver.) If you mess up the maneuver node, or if you want to delete it later for easier viewing, you can right click on it while it is closed and click the red X. 2. Add prograde velocity to the node by pulling out the yellowy green handle with an open circle. Keep adding velocity until your orbit's projected apoapsis is near the Mun's orbital altitude. You should get a Mun encounter right away doing this, since the Mun is a big target. 3. Slide the maneuver node along your orbit (grab the blue, central circle with the mouse to move it) and try removing some prograde velocity (pull the green handle with a circle + X.) Fiddle around with the position of the node and the amount of prograde/retrograde until you can get a projected Munar periapsis that is very low and so that you've also used as little delta-v as possible. Your orbit should not go out beyond the Mun's and back in order to reach it. 4. The navball tells you how long the burn should take and also how much time there is until the burn should be made. There is also a now a blue reticle on the navball that shows you the direction to point your ship to make the burn. Get oriented in the right direction, then timewarp until you are about half of the burn's duration before the burn is supposed to take place. (So if the burn is supposed to take 60 seconds, start burning 30 seconds before the maneuver node.) 5. Burn full throttle in the indicated direction. I personally like to delete the maneuver node shortly before it is finished (right click the node, click the X button to delete.) This allows you to see what your actual orbit is doing more clearly, rather than relying on the projection. Throttle back at the end of the burn and gently adjust your periapsis at the end. Try to get it to between 5 and 10km. If you accidentally go below 5km, turn your ship toward 270 degrees and burn just a smidge to correct the error. 6. Timewarp until you enter the Mun's SOI. You will either be going prograde or retrograde with respect to the Mun's rotation. Figure out which by seeing whether your velocity marker is along the 90 degree line (prograde with respect to rotation) or 270 degree line (retrograde wrt rotation.) If your periapsis is above 10km, now is the time to correct it. Turn in your vessel's retrograde direction (if your velocity marker is along the 90 degree line, turn to 270 with no pitch, if it is along the 270 line, turn to 90 with no pitch.) Burn gently until your periapsis is at about 5km. You can go a bit lower, but there's no sense overdoing it. 7. Timewarp until you are just before periapsis. Turn your vessel to point in its retrograde direction (again, if your velocity is pointing toward 90, turn to 270, and vice versa.) Burn in map view until your orbit is roughly circular. LMO --> Munar surface Now that you want to land you need to find a good landing site. Don't try to land on the night side just yet, and I would avoid landing on the side of a hill or mountain. The large dark craters near the Mun's equator are good sites; they are easy to see and flat. It's important to note that the altimeter gives your altitude above datum (sea level, basically) not the height above ground. Once you have found your ideal site, hit F5 to quicksave. You're probably going to wind up making a new crater on the surface once or twice before you get it right, so be ready to press and hold F9 to quickload. If you do want to quickload, try to do is as soon after crashing (or realizing that you're about to crash) as possible, because sometimes the game can be a pain about letting your quickload once the Mission Ended screen comes up. 1. In map view, timewarp until you are a short distance before your chosen landing site. You're not moving very fast at all, so there doesn't need to be much of a lead. Click your velocity reading on the navball to switch to surface mode. Orient your ship so that it is facing in your vessel's retrograde direction and burn to slow down. You should see your orbit sink into the ground, meaning that you're going to land (or impact anyway) when you get there. Switch back to vessel view and deploy your landing gear (G key.) 2. Keep burning retrograde, turning your ship so that you are always pointed at or slightly below the retrograde velocity mark. It will move up toward the zenith as you kill your horizontal velocity. In a perfect world the velocity would turn vertical at the exact same time it reached 0 m/s and you landed. In practice it never works out that nicely. If you are still well above the surface and get to 100 m/s or so, cut your throttle and fall some. Stopping completely (0 m/s) is a terrible waste of fuel. If you're comfortable with IVA, you can press C and use the radar altimeter to monitor your altitude above the surface once you are within 3km. 3. In any case, you want to burn retrograde until your velocity marker is pointing straight up (and so is your vessel.) Descend and try to use available visual cues (or the IVA radar altimeter) to monitor your height. When you see the vessel's shadow on the ground you are within 100-200m of the surface and should probably be thinking about getting yourself stopped. Again, ideally you'll be able to kill your velocity just as you touch down, but more realistically you can come to a hover shortly above the surface then drop down in several small steps until you land safely. As you land, ASAS can help keep your vessel upright if you bounce. Munar surface --> LMO 1. This is the exact opposite of an ideal landing. Find the 90 degree marker on your navball. Throttle up to launch and immediately turn toward it as much as possible, with no more than a 5 degree pitch. Switch to map view and get yourself into a low Munar orbit in much the same way that you did on Kerbin. 2. Once your apoapsis is above 5km and no part of your orbit shows you going through the planet, timewarp to apoapsis and burn to circularize. LMO --> Kerbin Surface 1. Set up a maneuver node on the side of the Mun that points toward Kerbin. Add prograde (green handle with an open circle) until your rocket shows a Munar escape. Adding a bit more will get you into Kerbin's atmosphere for an aerobraking maneuver and landing. This maneuver should only take 300-350 m/s, so if you've used more, slide the node around and try removing some velocity. 2. Make the burn as indicated by the maneuver node. If your projected Kerbin periapsis is below ~40km you will most likely wind up landing in one orbit. If it's significantly higher, you might need to orbit several times in order to land without using additional rocket power. 3. Don't forget to deploy your parachute (press space to use the last stage.) It will partially deploy at about 20km altitude and fully deploy 500m above the surface.

With good piloting you can get the stock Kerbal 5 to Mun orbit, but it doesn't have enough delta-v to actually land. A few small changes can get it to that point though (and I suspect give it enough delta-v to return to Kerbin if flown well.) 1. Replace the upper fins with LT-1 landing struts (utility tab) to turn that portion of the ship into a lander. As it stands this has far more control than it really needs, and the extra fins don't do a lot for it. 2. You can also remove the RCS tank and thrusters if you like. This will cut a bit of mass and give your rockets a bit more delta-v. If you like having RCS on a rocket of this type, keep it. 3. Remove the bottom of the rocket by taking the stack decoupler off and replace the LV-T45 engine that is now exposed (the one that is in the middle of the rocket to begin with) with an LV-909. The LV-909 gets better fuel economy and has significantly lower mass, giving you a ton more delta-v in the end (especially if you've also removed the RCS tank and thrusters.) Put the bottom of the rocket back on. 4. Rearrange the staging a bit. Right now it has solid boosters --> liquid boosters --> launch clamps --> decouplers. Move the launch clamps from stage 5 down to stage 7 (with the solid boosters), which will become stage 6 after 5 gets autodeleted. 5. Move the radial decouplers from stage 4 to stage 5 (with the liquid boosters.) Now when you launch it will go Solid + Launch clamps, then when the solid boosters burn out, Liquid + Decouplers. There is no benefit to keeping the original staging; it's overpowered and keeps you on the ground, wasting the beginning of the liquid boosters' thrust. I also like to move decouplers and engines into the same stage so that when an object decouples it is blasted away by the engine above it. As a result I would move the LV-909 into the same stage with the stack decoupler that is directly beneath it. 6. If you'd like to get a teeny bit more out of this rocket, you can delete the upper decoupler as well, as it really doesn't serve a purpose on this rocket. The parachute is more than strong enough to bring the entire upper stage down safely, and more importantly, the ASAS-command module connection is very weak, so when the parachute deploys it's very likely just going to break off there anyway. There's no sense carrying along a decoupler to do something that is inevitably going to happen on its own. If you do this you'll have a rocket with 4 stages: launch clamp + solid booster --> decoupler + liquid booster --> decoupler + LV-909 --> parachute With these changes the rocket will have enough delta-v to get to the Mun, land safely, and return to Mun orbit. I'm a fairly good rocket pilot, and I wound up 124 m/s short of being able to get back to Kerbin. It's very likely that I was off of the most efficient flight possible by more than 124 m/s, but it's not particularly realistic to assume that a novice pilot will be able to get a run that clean. If you can land safely on the Mun after making the changes I outlined, you're doing reasonably well. A rocket that was designed for this purpose would likely have another set of liquid booster stages rather than the solid boosters, and the outer boosters would feed fuel in to the inner boosters. Here is a screenshot of the ship I wound up with, including the staging. The LV-T45 engine that I replaced with an LV-909 is immediately below the lander legs.

I'm on your side llamatoes, you're missing E's! Those other letters are just wishing that they were as cool as E and imitating it.

I use 6 fold symmetry for the vast majority of my builds without ever having symmetry problems. If your payload is asymmetrical, it's going to cause problems whether you've got a 6 fold set of boosters or an 8 fold set. It could also be that your setup includes an accidental fuel loop (probably via a fuel crossfeed part) and that one side of the rocket is draining fuel faster than the other.

I leave all missions other than test flights active. It lets me see where I tend to land and also it's just kind of fun to see all of the vessel markers flying by as I launch. I really don't like to return my kerbals to the base. Perhaps with the addition of flags we'll be able to post something visible from a distance that says, "Jason was here!" but until then I'm going to retain my little pink reticles.

Well, I tried building a helicopter rotor with accelerometers both on the hub and at the ends of the blades. When it was ascending both accelerometers read the same value (1.5g in this case, though it ought to have read 1g, since it was ascending at more or less constant, incredibly slow, velocity.) After killing the engines and allowing the vehicle to fall, the accelerometers dropped to close to zero (free fall) then rose back to 1g after it hit terminal velocity. I have to think that this is measuring the CoM's acceleration only, and that it is not terribly accurate even there.

Yep, that's the infiniglide bug.

I wonder if the accelerometer only lists the acceleration of the CoM of the vehicle, rather than the acceleration of the accelerometer itself. Just a thought.

You can also use the BZ-52 Radial Attachment Ponit, which is designed for this purpose. In most cases the cubic strut is superior (because it is a non-physics part and is massless in the actual simulation) but the BZ-52 often looks better, in my opinion, and it doesn't cause problems when it is used with docking ports (and the cubic strut definitely does.)

The vessels are not considered as extended objects when you are away from them. Instead they are treated as point particles following an idealized orbit through space and their rotation is not calculated. This is good because it keeps the game running smoothly even when you've got zillions of missions going, but it's bad when you're trying to do something like get a vehicle to face a particular direction consistently. For a real vessel, like the ISS, the ship actually has to rotate constantly with a period that matches its orbital period in order to always keep the same orientation relative to the surface. In exactly the same way our Moon always shows the same face to Earth because it spins at a rate of 1 rotation per orbit.

You want to make your burn 90 degrees away from the point that you want to move. You can adjust the orbit from any other position (except right at the spot you're looking to move) but that will not give a symmetrically adjusted orbit; it will only be correct on one side.

The solution to infiniglide on a challenge like this is to limit the parts so that control surfaces aren't allowed. A good vehicle for this is going to be lightweight and steerable using command module torque.

The simplest is to get your vehicle into a stable orbit and then burn prograde (forward.) Your apoapsis will start rising, let it do so until its altitude is a bit past the Mun's orbit. Timewarp and you'll get an intercept after an orbit or three. This takes no more fuel to do than a planned transfer from LKO to the Mun, and it lets you see how your orbit will change as you increase speed. Try to note how it differs in burning from LKO to half of the Mun's orbital altitude, to the Mun itself, and to Minmus. Learning little things like this without using maneuver nodes or autopilots will really help you out in more advanced maneuvers later on. A basic understanding of what happens when you burn in direction X is invaluable.

Action groups are definitely the way to go for something like this, where you'll have multiple engines to turn on/off very quickly. They allow you to do it with a single keystroke. In case you're not familiar with them, in the VAB or SPH, there are two bright blue buttons in the top center of the screen. One allows you to adjust the parts in the vessel (and is active by default) and the other allows you to set up action groups. Click the action group button, choose the action group you want to modify (group 1, for instance) and then click on the part you'd like to add to the action group. It will give you a list of options, and here you would probably want to choose Toggle Engine. Generally speaking, toggle is a better option than Activate or Shut Down because it gives you more options, and if you accidentally fat finger the key too early, for instance, you won't have to fool around with manually resetting everything or wind up having to scrub the flight. There are some quirks with symmetry. If you've got two symmetrically placed engines, putting one of them in an action group will automatically include its twin. However, if you then remove the engine from the vessel and put it back on (like if you adjust the position of the wing that it is placed on), that will break the symmetry and only one of the two engines will be part of the action group. Unfortunately the interface doesn't show that this has happened, so you actually have to remove the engine from the action group and then put it back into the action group to get it working right. To make life more fun, occasionally the game will keep the symmetry and not remove the twin from the action group. In any case, it's easy enough to get around this, just set up your action groups as the last thing you do before leaving the SPH/VAB. For space planes I like to have an action group to toggle my jets, an action group to toggle my rockets, and a third to toggle my air intakes. Other people prefer a single action group that will simultaneously shut down jets and close intakes and activate rockets. The former allows more freedom - you can have rockets going at the same time you have jets going, for instance, in order to get the last bit of thrust from your jets, or you can shut your intakes but leave your jets active to drain excess liquid fuel and lighten the load on the rocket a bit. The latter is more convenient, especially if you're still shaky on piloting skills. ETA: I forgot to mention that if you do set up action group 1, you use it by pressing the 1 key on the keyboard by default. Action group 2 = 2, etc.