The engineering applications of orbital mechanics include ascent trajectories, reentry and landing, rendezvous computations, and lunar and interplanetary trajectories.Ī conic section, or just conic, is a curve formed by passing a plane through a right circular cone. The root of orbital mechanics can be traced back to the 17th century when mathematician Isaac Newton (1642-1727) put forward his laws of motion and formulated his law of universal gravitation. Orbital mechanics is a modern offshoot of celestial mechanics which is the study of the motions of natural celestial bodies such as the moon and planets. Orbital mechanics, also called flight mechanics, is the study of the motions of artificial satellites and space vehicles moving under the influence of forces such as gravity, atmospheric drag, thrust, etc. Newton's Laws of Motion and Universal Gravitation.Meaning - a one minute burn should start at minus 30 seconds.ħ) If you hit the node perfectly (slow down at the end so you don't go over then speed you need), and re-adjust your heading to stay on the blue maker, you'll emerge out of the burn with a pretty circular orbit. Your burn will be pretty long, so you want to try and balance it over the node. You probably don't have much time before the node comes up at this point, and you want to start you burn BEFORE the countdown gets to zero. You might have to play around until you get the nodes right where you want them - it's extemely sensitive when the apoapsis and periapsis are switching around.Ħ) So now you have a maneuver node set - time to align the navball to it - and quickly. At that point, they should be very close to being equal. It will be very quick.ĥ) Once you've found that spot, you want to back off the prograde a bit, and find the "sweet spot" when the apoapsis and the periapsis are about halfway around the orbit circle.
You're looking for when the apoapsis and perisapsis switch places. Got to the map, click on the apoapsis, and create a new maneuver.ģ) Add prograde to the maneuver until you get a periapsis pop up on the other side of the planet.Ĥ) Keep going with the prograde on the maneuver node, but go slowly now. Once your hit a decent number (for this exaple, we'll keep it simple - 100km), you cut the engines.Ģ) you should now have about 60-90 seconds to plan your next move - the circularization burn. During that time, you should be checking your map, and looking at where your apoapsis is. Here's a trick to help get a circular orbit:ġ) I'll assume you've launched, gone up to 10-15km, and then did your gravity turn. I think I burn too long and the myAP and PE start shifting around and the AP ends up higher and on the other side of the planet. Początkowo opublikowane przez Thievin Steven:Thanks guys, and yes it is tough to circularize an orbit at 70 km, I actually haven't gotten a good circular one yet. I've had too many instances where I'm still doing my burn while dropping past 60,000m, and thinking "I don't think this is gonna work. I find that if I need such a low orbit, it's actually easier to set my initial apoapsis at arounf 80-85, then set my periapsis at 70, then circularize when I get to the periapsis. you better have of heck of a powerful rocket to circularize a 70km orbit before you fall back down below 69km! Yeah, fair enough, but that's still cutting it very, very close lol. I remember that HOCGaming had something about this early in his Space Tourism series. The game counts you as being in-atmosphere at 70km ASL, but aerodynamics don't kick in until 69km ASL or less. Well, technically, you do have a kilometer of a "safety zone" within 70km. I've found that if I aim for a more realistic 90-100km orbit, I have more "leeway" to properly circularize my orbit without clipping the atmosphere.
If you were just at 70,000 when that happens, you're actually re-entering the atmosphere, and will start slowing down, compounding your problem. It's actually pretty hard to get a super low (70,000m) orbit, and circularize it, because the final orbit burn is usually a pretty long one, and it can easily keep going as you enter a negative vertical velocity state. Początkowo opublikowane przez ScruffyBamboo:To follow up on Trehek's good answer, many times the prograde maker will fall below the horizon if I'm trying to achieve an orbit that's too low.
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