# wmheric

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1. ## how do i modify my satellite network so that i can have zero downtime flying a probe?

Yes, you're right. Molniya orbits are for reducing the down time by lowering the proportion of time a probe spends close to (and behind) Kerbin, the relay satellite eventually goes into the "dark" side from time to time anyway. IMO Molniya constellations are much more tedious to set up/maintain/upgrade, and I always use equatorial circular orbits for relay outside the Kerbin system, unless I want low-orbit or ground coverage in the polar regions. I'd like to talk more about the single-antenna case, as the OP tries to use. A simple answer is no, you cannot. You'll need at least 2 antennas to g
2. ## Orbit vs Fly-By

This. According to the Wiki, whether a vessel has orbited around a body has an effect on the amount of science obtained upon recovery. Although the formula given is not a confident statement, I recall from my mission reports that orbiting a body returns more science points. How KSP determines whether a full orbit has been completed is also interesting to learn about.
3. ## Orbit shapes - why circular? How to calculate the path?

Hmm I'm not sure what kind of answer OP is expecting, but I kind of treat it as a physics question. Most have responded with explanations on ellipses / circles, yet why is a deeper question. In KSP, gravity is based on Newton's Law of Universal Gravitation, and in this classical picture of gravitation, a closed orbit is a perfect, eternal ellipse. It is a good description (an approximation) except in some special cases such as the precession of the orbit of Mercury, which later led to Einstein's General Relativity, which is a better description of gravity. Newton's gravitation does predict pre
4. ## Oberth effect and nodes.

I think what Blizzy was trying to say is that fuel requirement and a physics "effect" have no relation to each other. You do not "end up using less fuel for the same dv change". Given the same rocket design, the fuel requirement is always the same for a certain delta-v requirement. You save fuel because the delta-v requirement is less, the phenomenon that delta-v requirement is less at a higher speed is termed the Oberth effect; it isn't really something that pops up when you thrust -- it is just there. The answer to the question "do maneuver nodes take the Oberth effect into account?" is no,
5. ## [Orbital Mechanics] Efficient Plane Change I

My understanding is that after the plane change at Ap you come down to the periapsis to push Pe out to Minmus' orbit? The efficiency of the plane change burn depends on how far out the AN/DN is but is better than one at low-Kerbin orbit, although Minmus would have displaced some distance by the time you go back to the Pe so you may have to delay your burn. Burning at points other than the AN/DN would actually change the positions of AN/DN; you can still minimize the relative inclination but if you want it zero you have to burn at AN/DN. I usually do my plane change at AN/DN on the way to Minmu
6. ## [Orbital Mechanics] Efficient Plane Change I

Noticed you have more Keostationary satellites than you need and want to convert some into polar orbits to extend the network coverage? Having launched a probe mindlessly firing eastward into space just to find out that you actually need a polar orbit? Burning normal does help you change the inclination of an orbit, but if you have some experiences in orbital maneuvers, you probably already know that it is one of the most fuel-consuming one, and you probably also know, either from your own experience or from other players, that it is a fuel eater because you are burning perpendicular to your v
7. ## Pragmatic alternative to perfect orbits

I wouldn't consider this as a bug/feature. It is the nature of floating-point arithmetics. I think the objective of the mod is to add realistic features to the game by introducing possible communication blackout. It does gives the player more stuff to manage (to set up networks, to plan ahead, etc.). In reality, although there are no floating-point errors, there are perturbations (from the Moon, the Sun and other planets; from the asymmetry of the gravitational field, etc.) and engines have to be fired from time to time to keep a satellite in a stable orbit, though everything is controlled by
8. ## What are the most important things you've learned about playing KSP to pass on?

IMO the most important point in KSP: it is orbital mechanics, not driving on the road. If you want to get to a place, you can't just hit the pedal and get there; you don't change direction by just steering; we don't really have much "control" in this case, and indeed we don't -- essentially we are all slaves of gravity, we make a small change here, and hope that gravity will gradually bring you to the correct place. In the atmosphere, you may be flying a plane, but once in orbit, strictly speaking you are not flying anything; you just change something at a certain point, and you can only let g
9. ## best way to move your orbit from 90 back to 0

Derp. Thanks! You save more delta-V by pushing the apoapsis higher.
10. ## best way to move your orbit from 90 back to 0

Alistone is right: for a 90 deg plane change, the delta-V required is always smaller when you bright up the apoapsis and burn normal there, and it turns out that the amount of delta-V "saved" is smaller [EDITED: greater] for a higher apoapsis. The tradeoff is of course the total time (the period of the elliptical orbit) needed to finish the maneuver. Gravity assist by the Mun is an challenging and an exciting idea
11. ## Mechjeb: Geostationary Orbit at Different Longitudes

lodestar has a nice procedure above on how to do it with a probe carrying all the satellites in one single mission. For a 3-satellite configuration using a 4-hr transfer orbit, 1225.553 km is the number to go; for a 4-satellite configuration... A short answer: If you're using a 4.5-hour transfer orbit, 1658.030 km is the altitude you're looking for. A long answer: You need Kepler's Third Law, I wrote a tutorial to explain it. Yes it is quite long, but I hope that by the end you will know how to do the same thing with any configuration around any planet, because you understand the principle. If
12. ## Pragmatic alternative to perfect orbits

I think I get what the OP means by people missing the point. Speaking of the impossibility of perfectly circular orbits, orbits exactly matching a desired semi-major axis or a period, even with readouts from mods like Engineer Redux or MechJeb, are also, in principle, impossible because of the floating-point calculations. The issue is negligible in the beginning but if the player spends long enough with a save (e.g., multiple interplanetary missions could make you time-warp for tens or even hundreds of years), the errors start to show up as they propagate. Therefore, I'd say it is impossible t
13. ## [Orbital Mechanics] Kepler's Third Law - Launching Several ComSats in One Mission

Thanks a lot! Yes, the equation you derived is very useful for insertion into orbit at the right position and at the right time. It merits a post for discussion (got so many ideas on what to do next! ) Looking forward to your video
14. ## Perfect Satellite Orbits (Or, how to Hyper-Edit without Hyper-Edit)

Hi Scottiths, LPE is the longitude of periapsis, it defines the position of the periapsis as an angle relative to a reference direction. I don't know how it is internally handled in KSP, but for a perfectly circular orbit (ECC = 0), it doesn't make sense to talk about any periapsis (or apoapsis). I recommend you leave LPE = 0. As Fett2oo5 has pointed out, where the epoch (time elapsed since a time reference, the time t = 0) is defined by EPH. MNA is not "how fast your satellite is going". To set up satellites 180 degrees apart, you can set one of the MNA = 0 and another to MNA = 3.1416 (MNA i
15. ## [Orbital Mechanics] Kepler's Third Law - Launching Several ComSats in One Mission

The context of this guide is based on the real-world use of communication satellites put in geosynchronous / geostationary orbits. In short, a geosynchronous orbit is an orbit with a period the same as the rotational period of the Earth; a geostationary orbit is a special case of a prograde synchronous orbit in which the orbit is directly above the Earth's equator. If our focus is solely on equatorial orbits in the same direction as Earth's rotation, the two terms basically refer to the same thing. Having satellites in a geostationary orbit is a great advantage for transmitting signals to and
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