With news of latest push of another 1800 satellite going into space to create another global internet network.
How does so many satellites together with many other satellites stay in orbit without being a gigantic pileup in space?
In: Technology
Space ships are essentially falling continuously but at the exact correct speed that it slingshots around earth and maintains its orbit as it follows the curvature of earth and space.
Space is big. Much bigger than the oceans, and you wouldn’t expect an extra 1800 ships to constantly threat crashing in the middle of atlantic right?
Also their orbits are planned. For communication we want them to be geostationary so that when we point an antenna at a point the satellite stays there.
There are some satellites with more weird orbits but those are rather an exception.
Think about how much sky planes occupy. At any given time, there are up to 20,000 planes in the sky, compared to about 6000 satellites currently orbiting Earth (most of which are no longer operational).
Satellites orbit at different heights, ranging from 160km-2000km above the Earth’s surface (“Low Earth Orbit”) up to about 36,000km above the surface (“High Earth Orbit”). That is a tremendous amount of space. In fact, even though there are 3-4 times *fewer* satellites than there are airplanes, satellites have **38,000 times more space** to orbit than airplanes have to fly in.
Every satellite’s orbit is known and tracked. The physics of putting objects into orbit and maintaining them is very well understood.
Granted, this may become a problem eventually, but for now, it’s manageable.
A good visualisation are bullets on a battlefield, they are a lot, they travel from all directions but is really rare that a bullet encounters another.
A satellite is much smaller in relation to it’s orbit than a bullet is small in relation to the field.
In addition satellite orbit are tracked and adjusted to not interfere with each other.
Plus you have to consider that satellites are not just randomly spinning around the earth but (usually) following the “same” track.
In short it’s a LOTTTT of planning. Each satellite has its own specific orbit which is known and tracked. They have to get a satellite up to the right altitude and velocity to have an orbit that doesn’t cross another.
This is further complicated by the fact that there is in fact a very small amount of drag and the orbit changes slightly over time
How do about 8 billion people walk around the Earth without constantly walking into each other?
Space is a lot bigger than the surface of the Earth.
I mean ideally it’s a merry-go-round situation:
https://en.wikipedia.org/wiki/Carousel
despite the satellites chasing each other and being chased they should keep their distance to each other.
1. Space is *big*. Like, really big.
2. Orbits can be planned very precisely so we know where they all are and where they will be, and if we see them getting close to something we can steer them away ahead of time.
3. They do crash more often than you think. Maybe not into another working satellite, but into a tiny piece of trash that can cause damage. Just 2 weeks ago the crane arm on the ISS was hit by debris, causing a hole in the insulation: https://www.space.com/space-station-robot-arm-orbital-debris-strike
Space is crazy big, and compared to space satellites are small, even the ones that are the size of a bus are still small. There is a lot more room up there, and satellites are at all kinds of different altitudes. You could spend your entire life on a satellite and never see another satellite. Even if you were “close” to one it still would just be a glimmer of light, you probably wouldn’t even notice.
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