4 ms·
Yes, sorry, my phrasing is somewhat confusing. In terms of energy they are faster, since more speed is required for higher orbits. They appear to be slower in a
by gatonegro 4y ago
Yes, sorry, my phrasing is somewhat confusing. In terms of energy they are faster, since more speed is required for higher orbits. They appear to be slower in a relative sense when observed from Earth — the Space Station or a Starlink sat will appear to be moving significantly faster than a satellite in medium or high-Earth orbit.
It also depends on the geometry of the orbit — an object in a circular orbit will move at a constant speed, while an object in an elliptical orbit will move faster or slower depending on which point of the ellipse it is.
I understood the parent comment to be focused on an Earth-centred perspective, since they were talking about Kessler syndrome and Earth-orbiting debris. I was trying to address that point from an Earth-centred perspective too, but I appreciate how that can be confusing.
- scotty79 4y agoNo, no. You were right about the speeds and I was wrong. Higher circular orbits do have lower speeds. Starlink satellites have speeds over 7km/s while satellites on much higher geostationary orbit have little over 3km/s. I haven't built my intuition about why it's true but it is. Orbital speed is proportional to inverse square root of orbit radius.