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Post by alexey on Feb 1, 2017 8:18:26 GMT
Hello, everyone.
I've bought this game few days ago and since then I'am getting on flight controls. I have solid background with Kerbal Space Program, so orbital mechanics is not something new to me.
In KSP I was used to perform Hohman's transfers to intecept target, i.e. combining orbital match and phasing into one burn. There it was quite easy to implement even without autopilot mods.
Here I'am struggling to perform such maneuver. Usually I have to try multiple burn points along my orbit to find the one that lets me to intercept target. Sometimes I can't find one and have to perform two-stage intercept maneuver (match orbit, then phase orbit).
Am I missing something? Is there strightforward may to plan Hohman's transfer directly to intercept target?
Thanks in advance.
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Post by apophys on Feb 1, 2017 12:10:02 GMT
It's not much different than KSP, really. Only that KSP lets you move your maneuver along the trajectory after you've set the burn vector. Tip 1: Change your frame of reference for the job at hand. If you're moving between celestial bodies, it helps to use the common body they orbit around as your reference frame. For detail work, you can try switching to your target as your reference frame. Tip 2: Use the red knob first to get your trajectory tangent to your target's. Then fiddle with the green knob to change the timing of the intersection. Tip 3: Hover over points on your trajectory to see how everything else moves in that time. Tip 4: You can plan out multiple burns in advance. I like to set the entire route before progressing time at all. Once you start messing with custom modules, you might get spoiled by the glorious dV that MPD thrusters offer. You'll be doing brachistochrone trajectories for the most part.  Welcome to the game and the forum!  |
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Post by alexey on Feb 1, 2017 14:08:21 GMT
Thanks for answer, but I still don't get one thing: how to pinpoint exact moment of burn without multiple trial-and-error maneouver nodes creation?
KSP allows you to move existing node along trajectory, observing resultant orbits and encounters in real time as they change.
Is something like that possible here? Can I move existing node in time?
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Post by The Astronomer on Feb 1, 2017 14:30:38 GMT
Thanks for answer, but I still don't get one thing: how to pinpoint exact moment of burn without multiple trial-and-error maneouver nodes creation? KSP allows you to move existing node along trajectory, observing resultant orbits and encounters in real time as they change. Is something like that possible here? Can I move existing node in time? Notice that in orbit view, time in CoaDE does not run. You can try as many times as you can without worrying about setting it in time like in KSP. Moving nodes, however, is an interesting idea indeed. As a former KSP player, I fully support this. |
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Post by apophys on Feb 1, 2017 15:01:50 GMT
Until we can move nodes, you'll just have to get good at guessing where the node ought to be.
A rule of thumb I heard: do your burn when your target is starting to poke out of the horizon of the body you're orbiting.
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Post by The Astronomer on Feb 1, 2017 15:05:26 GMT
Until we can move nodes, you'll just have to get good at guessing where the node ought to be. A rule of thumb I heard: do your burn when your target is starting to poke out of the horizon of the body you're orbiting. That only applies if your SMa is much less than the object you want to reach's SMa. More and more error will occur if the SMa obj:SMa you ratio went less. |
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Post by theholyinquisition on Feb 1, 2017 19:21:23 GMT
It's not much different than KSP, really. Only that KSP lets you move your maneuver along the trajectory after you've set the burn vector. Tip 1: Change your frame of reference for the job at hand. If you're moving between celestial bodies, it helps to use the common body they orbit around as your reference frame. For detail work, you can try switching to your target as your reference frame. Tip 2: Use the red knob first to get your trajectory tangent to your target's. Then fiddle with the green knob to change the timing of the intersection. Tip 3: Hover over points on your trajectory to see how everything else moves in that time. Tip 4: You can plan out multiple burns in advance. I like to set the entire route before progressing time at all. Once you start messing with custom modules, you might get spoiled by the glorious dV that MPD thrusters offer. You'll be doing brachistochrone trajectories for the most part. Welcome to the game and the forum! !'m assuming that MPDs performing brachistochrone maneuvers is a joke. How would I optimize my maneuver for maximum intercept speed? |
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Post by Enderminion on Feb 1, 2017 19:31:24 GMT
It's not much different than KSP, really. Only that KSP lets you move your maneuver along the trajectory after you've set the burn vector. Tip 1: Change your frame of reference for the job at hand. If you're moving between celestial bodies, it helps to use the common body they orbit around as your reference frame. For detail work, you can try switching to your target as your reference frame. Tip 2: Use the red knob first to get your trajectory tangent to your target's. Then fiddle with the green knob to change the timing of the intersection. Tip 3: Hover over points on your trajectory to see how everything else moves in that time. Tip 4: You can plan out multiple burns in advance. I like to set the entire route before progressing time at all. Once you start messing with custom modules, you might get spoiled by the glorious dV that MPD thrusters offer. You'll be doing brachistochrone trajectories for the most part. Welcome to the game and the forum! !'m assuming that MPDs performing brachistochrone maneuvers is a joke. How would I optimize my maneuver for maximum intercept speed? I assume that MPDs have enough Dv to burn half way there and turn around and burn the other half |
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Post by theholyinquisition on Feb 2, 2017 1:09:59 GMT
!'m assuming that MPDs performing brachistochrone maneuvers is a joke. How would I optimize my maneuver for maximum intercept speed? I assume that MPDs have enough Dv to burn half way there and turn around and burn the other half |
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Post by newageofpower on Feb 2, 2017 1:56:11 GMT
*shrug* multi Gigawatt MPDs are the ships that are closest to being able to perform Brachistchrone manouvers. With a huge resistojet secondary thruster set, you can sacrifice some dV for fast deep gravity-well escapes, to boot.
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Post by argonbalt on Feb 2, 2017 2:43:07 GMT
Yeah i am still running tests on near Brachistrone/Hybrid burn orbits and movements. So far i have not had anything pure Brachistrone outside of the mercury MPD's. If time to target body is < than total burn time/2(or) Dv/2 than it is not a Brachistrone, this obviously assumes some pretty settings for orbited bodies/escape velocity etc. The hard part is getting that =T, ill spend some time playing with NASA's GMAT to see if it can help out.
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Post by apophys on Feb 2, 2017 5:41:33 GMT
!'m assuming that MPDs performing brachistochrone maneuvers is a joke. How would I optimize my maneuver for maximum intercept speed? Not a joke. Take a look at the Homecoming thread for an extreme example, burning 422 km/s dV to do the mission in 2 months 13 days. Burn partway there, cruise a bit, then turn around and slow yourself down (if you want to; a missile bus can just keep going with 30+ km/s intercept speed). Normal combat spacecraft I make seem to only go up to ~40 km/s dV, but that could be increased if desired by upscaling the reactor and propulsion system. |
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Post by zuthal on Feb 2, 2017 6:50:41 GMT
Two things in this game that might throw a player who is coming from KSP off:
1) Here, the maneuver preview recognises, that the engine burn takes time - in KSP, the maneuver node just assumes that the maneuver is an impulsive one (i.e. you burn all your delta-V at once), and requires you to figure out when to start your burn from the displayed burn time. Also, in CoaDE, you often have lower accelerations and thus longer burn times than in KSP, in addition to that fact that you are operating in the real solar system.
2) CoaDE recognises n-body effects, i.e. the influence of the gravity of objects other than your primary on your orbit. That means that especially in systems with a lot of objects, and with orbits that are very close to escaping altogether, the trajectory can get quite wonky.
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Post by alexey on Feb 2, 2017 7:43:41 GMT
Yeah, I've already recognized theese differences. Actually, I like it, because N-body simulation opens a lot of new possibilites and challenges in orbital maneuvering. Once I've wrote simple 2-D spaceship simulator with N-body mechanics and had a lot of fun flying around  Unstable and chaotic orbits are fun. |
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Post by Enderminion on Feb 2, 2017 15:00:18 GMT
Yeah, I've already recognized theese differences. Actually, I like it, because N-body simulation opens a lot of new possibilites and challenges in orbital maneuvering. Once I've wrote simple 2-D spaceship simulator with N-body mechanics and had a lot of fun flying around Unstable and chaotic orbits are fun. Do you still have it? |
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Unstable and chaotic orbits are fun.