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Not 100% sure this is the right place to post this, but I created a single-use widget for calculating resonant orbits to deploy satellites into a circular orbit at regular intervals along that orbit. It’s at http://meyerweb.com/eric/ksp/resonant-orbits/. In case you’re wondering “what the heck is this?”, a resonant orbit is most commonly used to set up CommNet constellations around non-Kerbin bodies. Suppose you want to put three relay satellites into circular polar orbit around Minmus. You could launch them one at a time from Kerbin and do all kinds of shenanigans to get them into a common orbit (say, 100,000 km above Minmus) at 120-degree intervals along that shared orbit. Which requires matching inclination and LAN and all manner of stuff, and then trying to jostle them into the right places along the circle. Or, you could build a carrier craft that hauls three satellites to Minmus, then release them one at a time. That solves inclination and LAN problems, but what about timing? The easiest thing is to put the carrier craft into an eccentric orbit with its periapsis at the altitude the satellites should share, and an orbital period 4/3rds the length the satellites will have in their circular orbit. In this example, the satellites’ final orbits at 100,000m above Minmus will have a period of 2 hours, 39 minutes, 29.5 seconds. So you put the carrier into an orbit with a periapsis of 100,000m and an apoapsis of 167,652.4m. That has an orbital period of 3 hours, 32 minutes, 39.3 seconds—exactly 133% the orbital period of the circular orbit. Having done that, you just release one satellite from the carrier as it passes periapsis on each of three successive orbits. Hey presto! You now have three satellites in a polar triangle, sufficient to cover the entirety of Minmus and maintain a network back to Kerbin. Quick, deorbit or otherwise move the carrier’s orbit so it won’t smack into the first satellite you released on its next periapsis. I built some spreadsheets to manage the necessary calculations for myself, but it seemed more fun to build a web-based tool that could draw a diagram of the orbits and all that while also spitting out exact Ap and Pe altitudes. And, while I was at it, show the minimum altitude for a functioning three-satellite setup as well as the edge of the SOI for whatever body I was trying to put satellites around if my orbits were large enough to be a problem, show atmospheres (where applicable), tell me the dV I’d need to inject each satellite into its final circular orbit, and stuff like that. It looks like this: It’s of fairly limited use, but it was fun to make and it supports stock as well as RSS and GPP. I figured if someone out there could make use of it, that was good enough for me to release it. Share and enjoy! (P.S. If anyone has feature requests, I’m happy to hear them, though I may not get around to actually doing them. I mean, I might do them, but I have a tendency to toss these little projects into the wild and then get distracted by some new project and never go back to update the old ones. So fair warning and all that.)
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Hi folks! As far as I've looked, I couldn't find anything like this, so here goes... I've tried to create an Excel workbook to help you calculate how much Δv a craft needs for different manoeuvres, including going to a stationary or resonant orbit, hohmann transfers and inclination changes. I'm Dutch so my OS (and by extension, Excel) is Dutch as well, but it should work fine on any other language. Here are some screenshots of the first release: https://imgur.com/a/AMqom Time for the first release! Hope you guys like it! I strongly advise you to read the instructions. Since my native tongue is Dutch I hope the translations make sense. If you have any advice for me to make things clearer, please don't hesitate to tell me. LINK! Changelist: How to use the sheets: This workbook is most suitable for, though not limited to, both stock and OPM installations of KSP. Calculate stationary/resonant orbit Use this sheet to calculate at which altitude your craft/satellite/etc. needs to be at, when you want it to stay above a specific point on the surface of the celestial it's orbiting. You can also calculate resonant orbits. In combination with the other calculations, it can help you figure out how much Δv your craft needs. Δv Hohmann Manoeuvre Use this calculation when you want to know how much Δv your craft needs to change orbit altitudes. This can come in very handy when building your craft. Δv Change inclination (e≈0) Use this calculation when you want to know how much Δv your craft needs to change its inclination. This can come in very handy when building your craft. However, this calculation method is only valid if your orbit is (close to) circular. If the eccentricity is too much, use the next sheet. Δv Change inclination (e<0) Use this calculation when you want to know how much Δv your craft needs to change its inclination AND it has an orbital eccentricity that's not (close to) 0. This can come in very handy when building your craft. (You can still use this calculation when the eccentricity is 0, but it’s not worth the hassle.) Free Sheet You are free to use this sheet any way you wish; to store your own values and/or make your own calculations. Things to take into account when working with these formulas - For the inclination change calculations, you need to use your judgement to decide whether to use the e≈0, or e<0 variant. - All the calculations assume you wish you change only that for which the calculation is suitable, nothing else. If you wish to change apsis and inclination at the same time, you’re out of luck, because that’s not included in this workbook and you can’t simply add up the results of formulas. It’s way more complicated than that. Disclaimer This workbook can help you out in KSP (and maybe some other games/simulators). Keep in mind though that as thorough and accurate as I have tried to be, errors may still have slipped in. I (the creator of this workbook) will not be held responsible for ruined games. Having said that, of course I would be sorry if something went wrong because of an error in this workbook. Would you kindly point it out to me in this thread. I’ve deliberately put a lock on all the worksheets (except the ‘free’ one), so the cells containing essential information and formulas are protected from accidentally selecting and changing them. I’ve also provided the password for each of them, in case you do want to change something. If you’d like to see anything added and/or changed, please ask me in this thread. I can and will not make any promises, except for taking a look. Please don’t spread this workbook elsewhere without consulting me first, thank you very much!