If there are many satellites orbiting earth, how do space launches not bump into any of them?
In: 2066
The opposite happens too: Launching to rendezvous with another craft is difficult. You might hear of instantaneous launch windows. Once something is in orbit its motion is no longer relative to the ground. So the launch needs to happen when the target object’s orbital plane intersects the launch site. The launch then needs to proceed into the same plane, and then enter an orbit that will intersect the other, then completely match orbits. Adjusting orbits costs delta V, which effectively means fuel.
So even launching randomly, to intersect the orbit *and* be there where the other thing is there, is not likely.
Space is big. That helps. Second, is that every satellite above a certain size is tracked and warnings are put out if there are predictions that they will approach to within a certain distance of each other so that the operators can decide whether to perform a maneuver. Obviously it’s not a perfect system, most notable when an active Iridium satellite collided with a defunct Cosmos (Russian government) satellite.
“Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the drug store, but that’s just peanuts to space.”
-Douglas Adams
Space is incredibly vast. Everything is very far apart. As an example, consider the rings of saturn or our asteroid field. You probably believe based on tv shows that these are huge rocks all tumbling together that would have to be dodged and avoided. The reality is however that the objects are going to be 600 miles apart from each other. When objects collide in space they lose energy and fall. This means that every object we see has to be in a stable orbit far enough apart from other objects where they no longer collide. The objects orbiting the earth appear to be stable but they all lose energy over time (from dust collisions) and will eventually enter the atmosphere and burn up.
Quite simple. Of the roughly 40,000 tracked human-created objects larger than a baseball in orbit around the earth (of which about 7500 are actual satellites and not just debris), if all of them were in low earth orbit at 500km, each one would have share of space approximately the size of Switzerland.
Space is so vast, and satellites are so small. I imagine it like two people with BB guns standing at either end of a football field who are blindfolded and asked to shoot their BB guns in the air. What are the odds of those two BB’s colliding in mid-air? Probably roughly the same odds of two satellites being on a collision course.
“Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space. Listen . . .” And so on
Space is a LOT bigger than you think, especially when you realize that you are talking about an infinitesimally small sliver of space.
We are very, very tiny.
In the word of Douglas Adams “space is big, REALLLLY big”.
He was right think of how big earth is then realize that 99.99% of space is empty. There is plenty of room up there. If I was actually good at geometry I would show how the distance from the land to orbit increases the sphere by an exponential amount but I am not so I’ll just say it as a concept.
it is crazy to me that an average person cannot fathom how large the earth is and subsequently how large the space around it is. (and I am one of those people too)
Our brains are… limited.
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