Anomalous_Matter Posted July 31, 2012 Share Posted July 31, 2012 Okay, so let\'s imagine that it\'s .17 and a new planet called Murz has been added to the game. If I were in a circular orbit around the sun and wanted to use a Hohmann transfer to get to Murz, is there any formula to calculate the time at which I would burn to transfer into orbit around Murz? Like, when transferring to the Mun from Kerbin, you have to wait until it shows up on the horizon; what formula did whoever discovered that use to find it out? Is it still at the point when it shows up on the horizon, or would it be different for every orbiting body?I\'m interested in this because in .17 planetary travel will become a must, so I\'m trying to learn some more advanced mechanics - however, I figured that if it\'s possible to just boost into solar orbit and then use a Hohmann to get to the new planet, it would be simple enough for me to do easily. Link to comment Share on other sites More sharing options...
Candre Posted July 31, 2012 Share Posted July 31, 2012 Woah, my calculations aren\'t matching up with what my program tells me. Someone else can take a crack at it, unless I figure out what went wrong. Link to comment Share on other sites More sharing options...
semininja Posted July 31, 2012 Share Posted July 31, 2012 What you do is find the period of the elliptical orbit you\'re using as a transfer, divide that in half; that\'s the period of your transfer. Figure out the angle that Murz moves around its orbit in that time, and subtract that from 180. What you get out of that is the angle with Murz that you need to be at when you start your transfer burn. Link to comment Share on other sites More sharing options...
Kosmo-not Posted July 31, 2012 Share Posted July 31, 2012 These calculation I made a while ago will give you the information you want:Alternatively, you can use my orbital rendezvous spreadsheet as found in my tutorial to get the same information (just be sure to change the gravitational parameter to that of the sun).Orbital Rendezvous Made Easy Link to comment Share on other sites More sharing options...
Cykyrios Posted July 31, 2012 Share Posted July 31, 2012 Seconding what semininja said, I\'d like to add that in orbit around a given body, the SMA is the parameter that gives you the period of your orbit. In a Hohmann transfer, you can get your SMA using your Pe and desired Ap (or Ap and desired Pe) + the body\'s diameter, and divide by 2. Then, as previously said, half of this time represents your transfer time, and you need to know the angle the other planet will move to rendezvous (note though, that planets have a bigger SOI, so you have a little room for error, though orbiting a star means that even a short burn can change your orbit by several km).Fun times will be had, and I hope Krakensbane will work Link to comment Share on other sites More sharing options...
Clouds Posted July 31, 2012 Share Posted July 31, 2012 the angle with Murz that you need to be at when you start your transfer burn.But how do you tell when you\'re at that angle in-game? I mean, 'Munrise' is a good way to measure 90 degrees, but there\'s no measuring tool in the game for arbitrary angles AFAIK (without mods)... Link to comment Share on other sites More sharing options...
VincentMcConnell Posted July 31, 2012 Share Posted July 31, 2012 But how do you tell when you\'re at that angle in-game? I mean, 'Munrise' is a good way to measure 90 degrees, but there\'s no measuring tool in the game for arbitrary angles AFAIK (without mods)...By distance. If you checked out Kosmo-not\'s spreadsheet, you\'d see that it judges by distance. So when the planet is a certain distance away from your orbit, you\'ll want to make the transfer. This brings the issue of launch windows and such, though. So going to other planets is really going to be a somewhat annoying thing. Link to comment Share on other sites More sharing options...
Kosmo-not Posted July 31, 2012 Share Posted July 31, 2012 By distance. If you checked out Kosmo-not\'s spreadsheet, you\'d see that it judges by distance. So when the planet is a certain distance away from your orbit, you\'ll want to make the transfer. This brings the issue of launch windows and such, though. So going to other planets is really going to be a somewhat annoying thing.You don\'t have anything to directly tell you how far the planet is from you. I referred to my spreadsheet because there\'s a page on there that you can enter the orbital information and have it tell you the phase angle to do your burn at. Your burn point with respect to Kerbin should be directly opposite the sun. Just be sure Kerbin and the target planet are at the correct phase angle. Link to comment Share on other sites More sharing options...
VincentMcConnell Posted July 31, 2012 Share Posted July 31, 2012 You don\'t have anything to directly tell you how far the planet is from you. I referred to my spreadsheet because there\'s a page on there that you can enter the orbital information and have it tell you the phase angle to do your burn at. Your burn point with respect to Kerbin should be directly opposite the sun. Just be sure Kerbin and the target planet are at the correct phase angle.Yeah, the fact that it doesn\'t tell you how far away it is is kind of a problem. Link to comment Share on other sites More sharing options...
semininja Posted July 31, 2012 Share Posted July 31, 2012 If you look at the map view, you can approximate the angle and adjust until an intercept shows up. Link to comment Share on other sites More sharing options...
maltesh Posted August 4, 2012 Share Posted August 4, 2012 But how do you tell when you\'re at that angle in-game? I mean, 'Munrise' is a good way to measure 90 degrees, but there\'s no measuring tool in the game for arbitrary angles AFAIK (without mods)..."Munrise" doesn't measure 90 degrees.In LKO, the Mun rises at approximately 30 degrees below horizontal, or about 60 degrees from the direction directly towards the center of Kerbin. Link to comment Share on other sites More sharing options...
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