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Hello, this is my inaugural post on the KSP forum. To learn some more physics and calculus, I'm trying to create an analytical equation for the path of a solid fuel model rocket fired vertically. I first made an equation assuming no atmosphere and no orbital mechanics, which I am satisfied with. I'm currently making an equation that accounts for drag, and assumes there is no change in atmospheric density and no wind. The equation I am using is from Wikipedia, specifically vertical motion upward and vertical motion downward. I am not sure how to adapt this equation to work while the thrusters are still active. If anybody can help me with this, I would be extremely grateful. The work I have done so far is here: https://www.desmos.com/calculator/ncmd38rosu The Variables folder contains all variables, the No Drag folder contains a complete equation that I have made personally, and the drag folder contains what I have done so far to account for drag. I am more than happy to explain my thought process/reasoning on how I have come up with what is on there so far. Thanks, and I look forward to spending more time with the KSP community.
How does aerodynamics in KSP works?
Yi C posted a topic in KSP1 DiscussionI am always wondering how aerodynamics is being calculated in KSP? For example, I want to know how does the game calculate the force produced by the wing(s) while flying in a specific speed. Any equations (as detailed as can be) will be appreciated.
orbital mechanics presentation
jevry posted a topic in Science & SpaceflightSo im holding a presentation about orbital mechanics for my exams and i need a tiny bit of outside help. -In the presentations I want to explain about some basic orbital mechanics and rocketry maneuvers. The presentation should be around a 10 minute. -For this presentation I also want to plan a fictional space flight to Europa that includes slingshot maneuvers (because that seemed like a great idea and my inner hipster did not want to go to mars because that seemed to mainstream). I believe the correct route would be from earth -> venus -> earth -> jupiter? -For this im assuming time is irrelevant and I can have any planet be at any point in it's orbit at any time (I will ofcourse disclaim this in the presentation). though I might want to know afterwards how long it may take for the planets to align how my route requires them, so then I can explain how the route isn't feasible (or is) because it will take too long (or won't) before we can launch the rocket. -I don't need to explain all the calculations exactly (I don't think) but the more formulas the happier I make the examinators (or so im told), though at the same time it needs to be understandable and approachable. Turns out it's not as easy as ksp makes it seem I've already figured out some of the basics of how to calculate and illustrate orbital trajectories. Things like the two focal points and one of those foci being the orbital body. i confuse the major/semi-major/minor axis (axi?) a little bit. I'm not completely read up yet on excentricity and the time it takes to orbit a body I do (I think) understand how you can calculate the distance with the velocity and vice versa with Msatalite*Vsatalite*Ddistance = Etot One of my biggest sources so far has been this site: https://www.astronomynotes.com/history/s7.htm In case its usefull here is a quick summary of how I so far think how I want to structure the presentation: part 1: explanation planetary orbits take Earth as example Earth moevs around the sun sometimes its a bit slower or faster and sometimes its a bit further away or close to the sun an explanation how you can illustrate the orbit around the sun with some formulas and focal points Stuk 2: doing orbital maneuvers with rockets launch reaching orbit and stabilising escape velocity orbit around the sun changing course: slingshot maneuver with venus and earth final course corrections ariving at jupiter arrivering at europa circularisation landing i've also learned what N-body physics means and.... i mean it's interesting an all as this lad shows of here: And I'm interested to see what will be up with the two planets in ksp2 that are "locked in a dance of death" since I heard those will get N-body physics (I may remember it wrong though). But honestly it sounds like eldritch science not meant for the human brain to calculate and fully comprehend (and it probably is, indeed, only meant for computers to math it out) and I don't think I need to calculate according to them in this case so some questions i have so far: -when performing a slingshot maneuver you gain speed equal to 2* Vp + Vr but is this different under different entree and escape angles ? does gravity, distance of the periapsis, and speed of the planet influence this? how can i calculate this and why has this not shown up in explanations before? -during interplanetary transfers, should i take into account that the planet you are escaping from will nudge your orbit a bit? (your periapsis (assuming your destination is farther away from the sun than earth) will be a bit higher than that of earth if im correct) -does anyone have any advice where to find calculations I need for the route im planning?
Hey guys! So today I was playing some KSP and I built a rocket which is meant to orbit Kerbin at a low altitude first and then increase the Apoapsis up to 1 000 000 km (So I can get some sweet science from low and high Orbit). After having achieved the 1 mil km I did a stupid mistake and I had to revert to start.This time, I decided to go for a more lazy approach. I decided not to achieve Orbit and just fly straight up. Now something happened which doesnt make any sense in my current understanding of the world. I was only able to achieve about 400 000 km - less than half the amount I was able to reach when flying in orbit. I dont know how this can make any sense: In my first flight I was spending way more time in atmosphere, why I should have lost more speed than in my second attempt. Also I just dont understand how flying vertically results in much lower altitudes than flying horizontally "only". I would be very happy if someone could explain the mathematics behind that. TY very much in advance!
Mun ejection angle
RizzoTheRat posted a topic in KSP1 Gameplay Questions and TutorialsI'm trying to do as much as I can with KOS in this career, which means actually working out what's going on rather than just eyeballing it with the manoeuvre nodes. Calculating the dV and phase angle to get to the Mun is easy enough, but I can't get my head around coming back. I know from previous experience that 250ish m/s at an angle somewhere between pointing at Kerbin and Mun retrograde will get me the most efficient return to Kerbin atmosphere, but can't see how to work it out. For a given Ap altitude above Kerbin I can work out the velocity I need to achieve my required Kerbin Pe, and for a given ejection burn I should be able to calculate the velocity and altitude relative to Kerbin at the point it leaves the SOI (not done this yet but I think I know how), but as the required Kerbin velocity will change with Ap altitude I can't see how to link the two together. Any suggestions?
When is a parachute safe to open?
RizzoTheRat posted a topic in KSP1 DiscussionDoes anyone know how to work out the safe opening conditions for parachutes? I found this interesting post from @Gaarston calculating terminal velocity with chutes but can't find anything on the safe limits. Presumably the safe limit is based on a maximum force, which will come from drag, so as the Cd and Area will be fixed for a given parachute type it'll be directly proportional to Dynamic pressure, Q. However I can't find any info on it. Using kOS to track Q of a fairly speedy capsule (3 mk1 capsules and a Stayputnik) as it re-entered, I found the Q peaked at about 36kPa when I stopped getting flame effects, it then dropped to about 14kPa, with the radial chutes turning white at around 18kPa, then Q started to rise again with the chutes turning orange at 31kPA and red at 35kPa. I've not entirely got my head around Q having 2 peaks though, I was expecting it to build to a peak and then drop off as it's directly proportional to drag, I guess there's some mach effects there increasing the effective area. The info on the radial chutes in the VAB says they have a tolerance of 4000kPa, which presumably isn't dynamic pressure as that would equate to about 2500m/s at sea level. I'm not even sure that could be a maximum dynamic pressure they can withstand when stowed as they'd presumably overheat and explode well before that. I did find an entry of "Breaking Force = 100" in the radial parachutes cfg file, but no idea what that could be as they're taking way more force than 100N, and I'd need to have a bit of a wade through the topic linked above to try and work out what the Cd and Area are to be able to calculate an actual force at my experimentally derived dynamic pressure to see if it's linked to that, but 100kN sounds too low to me. I might try sticking an accelerometer on a capsule to measure the force when the chute deploys to see if it relates to 100 anything. Anyone got any ideas?
How to get good at maths?
Inspierio posted a topic in The LoungeHello there, funny question here but I'm looking for different methods for revising maths. What's your best way of revising for tests?
Palaceviking posted a topic in KSP1 Gameplay Questions and TutorialsHey, does anyone know of a rough n' ready way of getting deltaV without using ln, ie I just want to do it on paper and get an approximate Value??
Sarahleth posted a topic in KSP1 Gameplay Questions and TutorialsMy plane was doing 0.13 fuel units per second, so i figured i'd time how long it takes to expend a unit of fuel, it took 23.56 seconds. But my calculations predicted far different from that result. My calculations are bellow. 0.13 units/s 1/.13 = 7.6923076923076923076923076923077 (seconds delay between each unit use) As you can see i predicted ~7.69 seconds, but i expirienced 23.56 seconds. A ~206.37% increase. I've added a screen-shot i took around the time of calculations in-case it helps. Can anyone tell me where i went wrong in calculations or if something like my frame rate is causing odd updates or something? (I had on average 11 FPS, and i timed the fuel expenditure with a stopwatch with 1/100 second accuracy. Also note that in the screen shot it has .09 but at the time of calculation it had .13)
Comm Orbits & Range
rockbloodystar posted a topic in KSP1 Gameplay Questions and TutorialsHi, i'm having some maths problems. Can anyone explain my error. I've ended up with relay stations with 32 HG-5 High Gains. (Based on maths, but i guess if this is wrong then that is too). Using the wiki I think the power of each relay is: (5*10^9)*32^0.75=6.73*10^10 As all relays are identical that gives a maximum link range of 6.73*10^10. Using the signal strength formula at a range of 2.20*10^10, i get a effeciency of: 1-((2.20*10^10)/(6.73*10^10))=0.67 0.67*0.67*(3-2*0.67)=0.75 (=75%) So, if I want a seperation of 2.20*10^10 in an equilaterl triangle arrangement I need an orbital radius of: (2.20*10^10)*(sqrt(3)/3))=1.27*10^10. I now have three such relays at a Kerbol Orbit of 1.27*10^10, yet not only are they not at 75% power, they are not linking at all. My initial hunch is that some of the measurements are from sun centre and some are from sun surface, but that only affects the third significant figure and smaller, reducing effeciency to 74%, not 0%. What is wrong with my maths (not just the aesthetic choice for the 32 antennae) Thanks in advance, RBS.
Satellite positioning around minmus
MR L A posted a topic in KSP1 Gameplay Questions and TutorialsHi guys, I've read a few posts regarding this subject, however I've failed to understand them. First. I'll explain what I am trying to do and why. I am using antenna range in lieu of the 1.2 KSP update which is alleged to add something similar. I currently have a probe landed on Minmus that loses connection when it cannot "see' Kerbin. I wish to place three satellites in an equilateral triangle formation which should be able to provide a constant connection. I have worked out that the minimum altitude required for this is 60km with 120 degrees of separation. I plan to put the satellites into a higher orbit than this to provide additional clearance for the signal from the surface of Minmus, I believe a higher altitude also provides longevity in terms of resonance between the three satellites. The three satellites are currently attached to a single vessel which is in an orbit of (or about to be in an orbit of) 60km x 20km. I understand the first satellite can deploy and burn prograde to 60 x 60 at any time. My questions are; What is "resonance" anyway? How do I work it out/alter resonance characteristics? And how do I work out when to deploy the second and third satellites from their given orbit into the desired orbit? I hope this all makes sense and my objectives are clear. I'm not an uneducated individual, however my maths skills are pretty poor, so terminology may need to be explained - though I did manage to workout the height of the orbit by simply constructing an equilateral triangle within a circle/orbit which is twice the radius of the given body (Minmus R = 60km. 2R = 120km. Altitude = 60km). Though please correct me if I have misunderstood this method. Thanks everyone!
Gravity turn maths
RizzoTheRat posted a topic in KSP1 Mods DiscussionsI've started fiddling with kOS and my usual programming technique is to look at what other people have done first and then pinch bits of various people's ideas to do what I want. So far all the launch scripts I've seen work by pointing the ship at a specific angle rather than doing a real gravity turn. I would like to programme a proper gravity turn, and then keep the ship pointing prograde, only making adjustments if it falls outside specified thresholds, which is kind of what I do when launching manually. My understanding is the initial turn will be dependant on TWR and drag. TWR I can easily calculate, presumably I could calculate a drag factor by comparing actually acceleration with the acceleration my TWR would produce in a vacuum? Anyone done anything similar? Anyone got any thoughts on working out the relationship between TWR, drag and the initial turn angle?