Timeline for What are these orientations called in orbit?
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 30, 2018 at 20:03 | comment | added | CoAstroGeek | The velocity vector is only perpendicular to the position vector for circular orbits or at apogee or perigee of elliptical orbits. | |
| Feb 11, 2014 at 21:33 | comment | added | Tristan | @Nickolai, the radius and velocity vectors will only be orthogonal in a circular orbit. | |
| Feb 11, 2014 at 16:26 | comment | added | Tristan | For most orbital mechanics calculations, the green arrows will be aligned with the R-bar direction, i.e., pointing directly at the planet's center. This does lead to a convention where the three axes are not mutually orthogonal, but the vector pointing to the planet center is more meaningful than an inward- or outward-pointing vector normal to the velocity vector. | |
| S Feb 10, 2014 at 16:45 | history | suggested | Nickolai | CC BY-SA 3.0 |
changed equator to center of planet, since equator is a line and you can't point to a line. Also added name for normal direction
|
| Feb 10, 2014 at 16:41 | review | Suggested edits | |||
| S Feb 10, 2014 at 16:45 | |||||
| Feb 7, 2014 at 14:56 | comment | added | Maxpm | I don't think so. In the question diagram above, the green arrows miss the planet's center. If the planet were smaller, they would miss it entirely. The velocity vector (represented by the red arrows) is only tangential to the planet's surface if the orbit is perfectly circular or the spacecraft is at its periapsis or apoapsis. | |
| Feb 7, 2014 at 14:45 | comment | added | PearsonArtPhoto♦ | I'm pretty sure that the velocity vector is perpendicular to the planet's center in any case, at least for relatively uniform gravity objects, like all planets and most large moons. | |
| Feb 7, 2014 at 14:42 | comment | added | Maxpm | The zenith and nadir always go straight in and out of the planet's center, right? So they're not necessarily perpendicular to the velocity vector? | |
| Feb 7, 2014 at 13:51 | history | answered | PearsonArtPhoto♦ | CC BY-SA 3.0 |