Eli5| Is orbit distance optional?

220 viewsOtherPhysics

Let me explain, I know the speed something orbit the planet is like 1,800 miles per hour, but is that like for a specific distance??? Could you go faster but at a lower orbit? Or Vice versa Slower at a much higher (or at this point further) orbit?

In: Physics

2 Answers

Anonymous 0 Comments

Orbital speed only depends on the distance from the center of whatever is orbited (that is: for a circular orbit; see below). The moon moves much slower than the ISS.

This doesn’t mean that higher orbits take less thrust. They move slower where they are, but the higher energy/speed to get that high more than offsets this lower orbital speed.

The speed along elongated orbits (ellipses) varies. The closer to the center, the faster it goes. The average speed however only depends on the largest diameter; any two ellipses that share it result in the same time per orbit (or crash into the planet).

Anonymous 0 Comments

Yeah exactly, the further away from a planet you are the slower you can move and stay in orbit – for example, the international space station orbits close to earth at 4.8 miles per second, while the moon (much much further away) orbits at only ~0.64 miles per second.

It also has a further distance to go, which adds up to why it takes the moon a month to complete a single orbit while the ISS does roughly every 90 minutes.