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Everything posted by blizzy78

  1. On the other hand you could argue why one would want to do the math themselves. After all it's a game, not an algebra course. If all I need is a minimum of delta-v, some reasonable TWR, and a rocket that can hold direction if told to, then I'm rather going to go the mods route to help me out. But that's just me of course.
  2. I'm always going with - 10 km turn start - 100 km turn end - 25% shape regardless of vessel characteristics. I've done a few tests with the Kerbal X some time ago, and 25% shape gave me the best result, so I sticked to that.
  3. Changelog: 2013-06-18 Added some general tips and tricks. 2013-06-27 Added some advice about approach speed when close to the target.
  4. (Note: I've also made in-game tutorial mods for rendezvous and docking. Perhaps these are more fun to you than to watch a silent video and read lots of text.) Hi, I've made a video showing how to launch a spacecraft, rendezvous with another vessel and finally dock with it: As the video is not narrated, I'm going to explain the different steps in this thread. A Few General Tips and Tricks Quick save/load - Press F5 to quick save, F9 to quick load. Use it often. Pressing M toggles between vessel view and map view. Press DEL on the numpad to toggle the navball while in map view. Timewarp kills all rotation of a vessel should that be necessary. Press . (dot) to increase timewarp level, press , (comma) to decrease timewarp level. To kill rotation, just enter timewarp for a second, then leave it again. You can also use SAS to kill rotation. Press T to toggle. Step 1/2: Launch Spacecraft (0:00 min) In these steps, I'm launching a docking target into a 300 km circular orbit, and then launch another spacecraft into a 100 km circular parking orbit that is then going to rendezvous and dock with the former. Spacecraft For this tutorial I'm using a slightly modified version of the stock Kerbal X: At the top, I've removed the parachute and the landing legs, and instead equipped the following: An RCS fuel tank Quad RCS thrusters in two rings of 4 each. Both rings are attached so that they're about the same distance away from the center of mass of the last stage. An ASAS controller A docking port See 12:37 min in the video for a closeup of those modifications. I've also modified the staging a little by moving the rocket holders into the same stage as the engines. Launch On the launch pad, it is helpful to first activate SAS by pressing T. This will enable the spacecraft to hold its orientation while in flight without flipping over or do other stupid things. To launch, throttle up fully by holding the Shift key. When at full throttle, press Space to fire the engines and release the rocket holders. The spacecraft should be going up vertically now. The Kerbal X has 3 booster stages to help its ascent. You can see that in the lower left corner of the screen. As soon as one pair of booster tanks are empty and their attached engines switch off, press Space to detach these. This is done three times with the Kerbal X. When the third pair of boosters is detached, the spacecraft should still be below 10 km altitude (see the altitude indicator at the top of the screen.) Going Into Space Reaching a stable orbit involves going around the planet, which is what we haven't done so far. Nevertheless it is necessary to first go straight up to leave the thick part of the atmosphere that is slowing us down. At 10 km altitude, it's time for a change. As soon we reach the 10 km mark, we switch off SAS by pressing T. Then slowly turn to the right (which is east on the planet) by pressing D. Notice that the prograde marker will follow you on the navball at the bottom of the screen. Keep turning the rocket slowly towards east while also maintaining only a short distance to the prograde marker on the navball. Do this until you reach the range of 0 to 20 degrees relative to the surface. (On the navball, the surface is the brown area, while the sky is blue.) When done turning the rocket, press T to activate SAS again. (Note: You can turn the rocket by using WASD on the keyboard. W/S is down/up, A/D is left/right.) Now switch over to the map view by pressing M. Rotate the view with the right mouse button held down to see your current trajectory (blue line.) You will notice that right now you will eventually crash into the planet again. We're going to fix this in a moment. But first let's bring our apoapsis (the point farthest away from the planet) outside the atmosphere. Let your mouse hover over the "Ap" (=apoapsis) marker on your current trajectory. Notice that the altitude of the apoapsis is rising. Let it continue to rise until 300 km. (You can slow things down by throttling down by pressing Ctrl.) When your apoapsis reaches 300 km, kill all throttle by pressing X. Press Space now two times to detach the last stage and activate the next engine. Reaching a Stable Orbit So far, you've done the hardest part of going into space. But to prevent crashing into the planet you must achieve a stable orbit. In the case of Kerbin, this means not only raising apoapsis outside of the atmosphere, but periapsis (the point nearest to the planet) as well. Note that your spacecraft reaching apoapsis is still a few minutes out (hover over the "Ap" marker on the current trajectory to see that.) To raise periapsis, we're going to use maneuver nodes. With the left mouse button, click on the current trajectory exactly where the "Ap" marker is. This will create a new maneuver node at that point. There are a few things that can be done with those nodes. To raise periapsis, locate the prograde marker on the maneuver node and click and drag it out slowly. Notice how a new trajectory will be projected. If you drag the prograde marker for long enough, the projected trajectory will more or less become a circle, with a new "Pe" (periapsis) marker appearing on it. Keep on dragging until the new apoapsis and periapsis markers are more or less at 300 km. Turn the spacecraft to point right at the maneuver node marker on the navball by pressing WASD. When done, press T to activate SAS again. Now that you have a maneuver node set up, it is time to execute it. To the right of the navball it is indicated how much Delta-v (change in velocity) you need to invest, how long the necessary burn will be, and the time to the maneuver node. For best results, you will want to time the burn to take place 50/50 at the time of the maneuver node. For example, if the necessary burn is 20 sec long, you will want to start burning 10 sec before the maneuver node and kill throttle 10 sec after the maneuver node. Activate timewarp by pressing . (dot) on the keyboard. Keep timewarping until shortly before the burn start time, then kill timewarp by pressing , (comma.) When it is time to burn, throttle up fully by pressing and holding Shift. Notice the yellow progress bar going down. When the burn is complete, press X to kill all throttle. You can also slow things down a bit at the end of the burn by pressing Ctrl to throttle down a bit. Nevermind the wobbling maneuver node marker on the navball at the end of the burn. You can delete the maneuver node now by left-clicking it (to select it), right-clicking it (to bring up the delete icon), then click the little X icon. Congratulations, you should now be in a stable 300 km circular orbit around the planet! Make sure SAS is active by pressing T. This will help when docking with this vessel. Launching the Docking Vessel So far we have a docking target in orbit. Now repeat all the previous steps with a second spacecraft, this time bringing apoapsis and periapsis into a 100 km orbit instead. Step 3: Adjust Relative Inclination (3:00 min) In the map view, you will notice that the orbits of our two spacecraft are most likely not aligned exactly - they are on different inclinations. (You can skip this step if they are.) To fix this, first click on the docking target vessel, then click "Set As Target". Notice there will be two new markers on the trajectory line, labeled "AN" (ascending node) and "DN" (descending node.) These are the points where the two orbits intersect (regardless of different altitudes.) Click on the current vessel's trajectory line right where the "DN" marker is. This will add a new maneuver node. Click and drag the normal marker of the maneuver node until there is a significant change of positions of the project "AN" and "DN" markers on the project trajectory. This usually indicates that you dragged the "normal" marker far enough and that the projected relative inclination is close to zero. Execute the maneuver node as you did before. When done, delete it. Step 4: Establish Transfer Orbit (4:17 min) Now it is time to plan our rendezvous with the docking target. Click anywhere on the current trajectory line to create a new maneuver node. Drag out the prograde marker until the projected orbit intersects the target's orbit. There will be new markers that indicate intersection points. Hover over those to see the projected closest approach distances. Notice that it will most likely be very far away. You can now modify the time of the maneuver node by dragging it around the current trajectory. To do that, grab the maneuver node by its little "ring" and dragging it around. If you're lucky, a little bit of dragging should bring one of the intercepts down to as little as 5 km or even lower. It might also be possible that you have to wait for a few orbits to get a good start (use timewarp to do that.) When you have a good maneuver node set up, execute it, then delete it. You're now on an intercept course. Step 5: Setup marker node for braking (5:55 min) The next thing you will want to do when near the target is brake again. Ideally the relative velocities between the vessels is zero. To do so, create a new maneuver node at the intersection point. However, there is no need to adjust this node, we're just going to use it as some kind of marker in time. Step 6: Brake (6:52 min) Timewarp until you get close to the maneuver node - about 30 sec before should be enough for this tutorial. Turn your spacecraft so that it points into the direction you came from, which is the retrograde marker on the navball. Activate SAS to keep orientation. When at the maneuver node point in time, throttle up to brake. Ignore the node's progress bar and burn time. Notice that the navball should be displaying velocity relative to the target (it should read "Target" at the top.) If it doesn't, click at the text until it does. What you will want to do is to bring your velocity relative to the target down to ideally zero. So at the end, the navball should ideally read: "Target 0 m/s" You should now be in relatively close distance to the target (5 km max.) Step 7: Approach (7:22 min) Turn the spacecraft and point it right at the target marker on the navball. Throttle up a little and watch the prograde marker move towards the target marker. Make sure not to go too fast now. You can kill throttle at any time by pressing X. If you're going too fast, turn the ship around to point at the retrograde marker, then burn to brake. Making the Markers Match This is actually quite easy once you get the hang of it. What you will want to do is move the prograde marker onto the target marker on the navball. That means your vessel is moving right in the direction of the target and not just flying by. The trick is in how the prograde/retrograde markers react when you burn: The prograde marker (direction you're moving in) will always move to the current location on the navball when burn - you're "dragging" it towards yourself by burning. The retrograde marker (direction you came from) on the other hand is always being pushed away from you when burning. So with this knowledge it is quite easy to move the prograde marker onto the target marker (while at the same time the same will happen with both vessel's opposite markers.) Approach Speed In this step, you're wanting to approach reasonably fast, but not so fast that you don't have time to react. I personally use a simple formula: Take the distance to the target, multiply it by 10, then use that value in m/s for the approach speed. For example, say you're 2 km away from the target: 2 times 10 is 20, so just use 20 m/s for your approach speed. You can gradually slow down when getting closer. Position Target and Activate SAS (9:15 min) In the video I've switched to the target by pressing \ (backslash), turned it some way and activated SAS to keep its orientation. Then I've switched back to the first vessel by pressing \ again. Step 8: Switch To "Chase" Camera (11:19 min) Now switch to "chase" camera mode by pressing V repeatedly. While being confusing at first, this camera mode is extremely helpful when docking. Step 9: Use RCS to Get Closer (12:13 min) Turn the ship to point at the target and activate SAS. Now also activate RCS by pressing R, then thrust a few times towards the target by pressing H. There is no need to go fast, about 0.3 m/s should be quite enough. You can timewarp if it's too slow for you. Without turning the vessel, brake again when near the target by pressing N. You should now be really close to the target with ideally zero relative velocity (that is, a standstill between the two.) Step 10: Move Parallel (12:44 min) Now you will want to move parallel to the docking axis. Simply turn around the vessel by pressing WASD so that the docking port is on an axis parallel to the target's docking port's axis. This can be done without RCS. Activate SAS again to kill rotation. Step 11: Move In With RCS (13:26 min) At this point we are all aligned with the target and just need a little translation with the use of RCS. Move the camera behind the vessel. Activate RCS again and begin translation: IJKL works the same as WASD, but for RCS translation this time (that is, no rotation.) Keep moving until the axes of both your docking port and the target's docking port align. You can move the camera around to check things from all sides. To move along the docking axis without translating (that is, "go forwards" or "backwards"), press H or N. Step 12: Move Forward to Dock (14:42 min) Now it's time for the final step. Your vessel is sitting perfectly on the docking axis and just needs a little push to finally dock with the target. Press H to do so. A relative velocity of 0.1 m/s is just about right. Congratulations, you've just docked with the target!
  5. Ohh, thank you very much. No more tweaking the DLL code for me
  6. Which is why I've gone the route of hacking the DLL to stop deposits from running dry in my game. I rather enjoy the benefits of having a permanent mining and conversion base on Ike. Edit: That being said, it is not the first base I've built. I've even moved one to another location when its deposit ran dry. I just don't think I will ever want to do that again.
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