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king of nowhere

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  1. king of nowhere's post in How to eject into a resonant orbit? was marked as the answer   
    No, no real formula that I know of - maybe one, but later about this. You just have to calculate, manually, your orbital time.
    The good news is, it's easier than it looks like; i recently learned it, and it worked immediately.
    I made a very simple datasheet to calculate this

    As you can see on the red circle, the two lines of numbers are just iterations, where the same numer is added over and over. In this case the upper line is the orbital period of Eve, and the lower line is the orbital period of my spaceship. So, the first line is just telling me that eve will return to the same position after 261.9 days, and then after 523.8 days, and then after 785.7.... while my spaceship will return to the intercept in 174.6 days, and then the next time in 349, and so on.
    And i just manually look if some of those numbers check. In this case, the datasheet shows that in 523.8 days eve will pass again through the intercept having made 2 orbits, while my spaceship will pass in the same spot at the same time having made 3 orbits, so a 2:3 resonance. But i used a 9:10 on kerbin earlier, and it's not any different.
    If the numbers don't check, i look where the numbers are closer, and I try to refine it. For example, in this case maybe i started with 180 days of orbital period, saw i would be late for a 2:3 resonance, and tried to adjust for a faster orbit. if that was not possible, i could have tried for a 3:4 resonance, and so on. there are more refined ways and more accurate tools, but this one suffices.
    Manuever-node wise, the way to do it is to set up a manuever node (without any actual deltaV used) after the gravity assist. it will tell you the new orbital period. so you try to adjust your flyby so that the new orbital period, shown in the second manuever node, will match what you calculated. You can't see your new orbital time when you adjust the flyby, you have to tinker with the correction manuever blindly and then select the second manuever node and see if the orbital time is right. however, with a bit of trial and error you can do it. and if your new orbit is a few hours shorter or longer than it should be, a correction manuever to fix that is cheap - so long as it's just a few hours.

    This image shows one such manuever planned. You can see the new orbital period, 385 days, in the bottom left corner of the image; it's the 9:10 resonance with kerbin i calculated. you can see the manuever node selected.
     
    Now, i said that there was some formula in addition to all this. Namely, there are 2 other mathematical boundaries.
    The first, and most important, is that you leave your planet after the flyby at the same speed you arrived, only in a different direction. example of why this is important: after my third kerbin flyby, i reached an intercept to eve. i was aiming for moho, and from eve to moho a transfer takes roughly 1000 m/s excess speed (in addition to eve escape). but my trajectory from kerbin had a 600 m/s intercept speed over eve. Guess what? No matter how much i tinkered with the trajectories, i could never intercept moho the way i wanted. I had to provide the additional 400 m/s with a burn at eve periapsis.
    So, if you've ejected from earth at the minimum excess speed, you won't ever be able to reach jupiter with any amount of flybys. you need two planets to bounce against each other, gaining energy at every step. on kerbin you can also use mun, if you include a mun flyby you can leave kerbin at a different speed than you had coming in. but the real moon has too much of an orbital inclination and too slow an orbital time for this to be practical. On the plus side, if you left earth on an inclined orbit, you can use the flyby to change your orbital inclination for free.
     
    second boundary, every planet can give you an assist for a limited amount of deltaV - the closer the pass, the higher the deltaV. if that deltaV is not enough, you have to make multiple passages. For example, kerbin can give you roughly 500 m/s kick, maybe 700. if you are coming from jool, excess speed of 1000 m/s, and you want to go to eve, you can do it - convert your excess speed of 1000 m/s going away from the sun to 1000 m/s going towards the sun.
    But you won't be able to do it in one passage. not even in 2. you have to first lower solar apoapsis, ejecting into a resonant orbit to meet kerbin again, lower apoapsis again, into another resonant orbit, and finally you can leave kerbin with kerbin as your solar apoapsis. because you had to change your speed by 2000 m/s, and kerbin can give at most 700 m/s, so you needed no less than 3 flybys. I can't give you hard numbers, unfortunately. especially not for rss.
     
    I hope I was clear. In addition, I can link you to the mission report where i describe how i went from ike to moho with resonant gravity assists. It took very long, but it was surprisingly cheap, and very rewarding. and my mothership didn't have enough deltaV to do it any other way. It is described in detail, so you may get some additional information.
     
  2. king of nowhere's post in Eve Contract was marked as the answer   
    as far as i understand, it wants your rover to have the "splashed" condition, which requires landing in water. no need to have a biome named "ocean". in fact, no need to get a liquid biome at all; somebody achieved the "splashed" condition on kerbin's desert, because there are a couple oasis
  3. king of nowhere's post in How to do a crewed Duna and/or Eve flyby? was marked as the answer   
    well, of course the mission is possible. you need to get the right gravity assist from duna to get into an eve intercept trajectory.
    now, the basics of gravity assists is that if you pass in front of the planet you decelerate, and if you pass behind the planet you accelerate. so, to get to eve, you want to lower your solar periapsis, you need to decelerate, you definitely want to pass in front of duna. to reach eve at the first orbit, though, requires special planetary alignment, and i'm not sure how much you'd have to wait for a chance like that
  4. king of nowhere's post in Tiny unKerballed probe into LKO? Stability trouble over 25km. was marked as the answer   
    A battery looks big, but it's just 5 kg.
    a parachute, on the other hand, is no less than 100 kg - unless there is some modded lighter version.
    on a probe so small, it may actually be more convenient to mount a more powerful engine and rocket brake.
  5. king of nowhere's post in Tiny unKerballed probe into LKO? Stability trouble over 25km. was marked as the answer   
    yes, SAS won't help if you leave it turned off. or perhaps you have it on, but then the probe goes in shadow, the batteries run out, and sas deactivates.
    Yes, you should add a battery. the basic one is a bit bad for aerodinamics, but there is the stackable circular one that you can put between the body and the nose cone for only 10 kg.
    then the octo does not have the functionality to hold directions. it will keep your probe still, but it will not point to any specific direction. you have to direct it manually. you said your probe was drifting, right? i assume you were trying a prograde burn, started with the prograde indicator there, and then the probe gradually shifted away from the indicator? in this case it's not the probe drifting, it's the prograde direction drifting. as you circle the planet, where is prograde changes. so yeah, you will have to make the manuever by hand holding the direction and compensating for that.
    Finally, i also see in the picture that the probe icon on top is in yellow. which means it has somewhat limited functionality. it's in the sun, so it has power. perhaps it is still hybernated?
  6. king of nowhere's post in Precision landing on bodies with an atmosphere was marked as the answer   
    my way has always been to save and reload until i got there. even then, it's difficult. only with a lot of effort i can even hit the biggest island on laythe.
    but if you don't mind wasting some fuel, there is a shortcut: make a high speed pass in the atmosphere. then, when you approach the target, burn your rockets.
  7. king of nowhere's post in Eve lander keeps sliding sideways until it breaks was marked as the answer   
    both. it''s a glitch, but can be prevented with design
    as far as i can tell, the problem is landing legs. the ship is bouncing on them too hard. the ship works on kerbin, but eve has higher gravity. the ship weight is pressing down hard against the landing legs, causing malfunctions. i have encountered a similar problem.
    possible solutions:
    - try to add landing legs
    - try to tamper with spring values in the landing legs
    - try to use a different model of landing legs (i only had this problem with that specific model)
    if you can find a solution, please tell me which one it was, since i had the same problem myself
  8. king of nowhere's post in Docking Encounter Tips was marked as the answer   
    so, you have your ship you want to reach in orbit.
    you start by sending your new ship in an orbit inside it, touching it on a point. if your target is on a 80x80 orbit, you want to be on a 80x75 orbit.  of course, fix the orbital plane first (there are ways to skip this, and they save a little bit of fuel, but are harder)
    so, the smaller an orbit is, the shorter it takes. the ship in the smaller orbit will slowly gain on the other one. this will let you reach a ship ahead of you - i generally target for this situation when i lauch for a rendez-vous. if instead you are ahead of your target and you need it to catch up, just increase your orbit a bit, still touching your target. in this example, an 80x85 will do.

    here is an example. i am commanding the space station and want to reach the plane. i am a bit ahead of it, so i put myself in a slightly larger orbit, so the plane will reach me in a few orbits.
    keep this difference small, the greater the difference in the orbits, the more fuel you'll have to use to equalize the two vessel's speed

    ok, so here we see the orange marker for the next close encounter. the plane will still be behind me. we set up a manuever node just after the close encounter

    now that we set up the manuever node, the game calculates the closest approach after the node. this means in the next orbit. so in the next orbit the plane will be closer, but still behind us. so we right-click on the manuever node and shift it ahead by one orbit

    now the manuever node is 2 orbits from now, and it says that in the third orbit, the plane will be slightly ahead of us.
    that's just what we want! now we only have to make sure that instead of being ahead of us, it just reaches us perfectly.
    to do so, we must accelerate just a bit, enough to cover those 29 km that the plane will have made past our position.
    and to accelerate, we need to burn retrograde. our orbit gets smaller, and we accelerate and gradually catch up to the plane again, until we have a near perfect encounter

    you don't even need a manuever node; just burn retrograde very slowly, and you'll see the close encounter marker gradually shift.
     
    i hope that was helpful.  the  key is to have the two orbits intersect in one point, and then burn in that point, prograde or retrograde depending on whether you need to go slower or faster.
  9. king of nowhere's post in Editing a craft file to remove fuel? was marked as the answer   
    easy enough. you open the file, there you have a list of parts. parts that can store stuff that can be consumed (fuel, ore, electricity) have a "resource" tab. there you can set your value as you will. under the spoiler you will find such a part, with the relevant resource parts highlighted.
    what's actually difficult is figuring out on which tank you are actually removing resources. it may be more convenient to empty all of them and refill manually those you want filled
     
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