Maybe this should be in Nostupidquestions as I’m aware the moon exists. And I guess there may be an orbit zone where things tend to remain in orbit. But curious…
The full context question is: For man-made satellites, would they benefit by having a “Self destruct” button?
Sure it may add more debris but since an explosion would scatter debris in all directions, anything flung up or down would cause it to get out of this geostationary zone/band… And hopefully come crashing down to Earth, reducing overall debris? Compared to an abandoned satellite, remaining in orbit and breaking down due to relatively low energy collisions with surrounding debris.
Basically I’m trying to justify self destruct buttons. Thank you!
All orbits require very minimal maintenance, the closer to earth, the more maintenance required . Far enough out, and its basically maintence free, except for avoiding other debris.
The problem with an explosive self destruct is that not all debris will go down into lower orbits, some with go higher and therefore take even longer to deorbit. Its also a lot easier to track one dead satellite instead of thousands of minute particles.
And ideal “self-destruct button” would actually be a thruster firing in the direction of travel, which would slow it down and drag it into the earth, or if facing the other way, boost it up to a “graveyard” orbit. Both these exist on many satellites already.
As an addendum to this comment:
The moon is also a source of orbital pull and does affect everything on the inside of its orbit and is probably the most significant source of disturbance at geostationary distances.
Also, even if they don’t, it’d be possible to send another spacecraft up that has enough fuel to deorbit the satellite.
Theoretically, anyway. It’s still experimental to do so, and the fact stuff is quite often spinning makes it harder.
IIRC using laser ablation is also a legit technique in consideration to give old space junk a push.
Wont you eventually leave orbit if you are too far away?
Depends. Do you mean around a conceptual single body in an infinite void, or are there other things out there?
The (circular) orbits in a gravitational well don’t end, they just get slower and slower as you move outwards forever. But, in real life you’ll be in a zone where other things have just as much pull after a while, and then anything could happen.
Yes, but I beleive that is quite a significant amount of energy to reach. Only a few spacecraft have left earths orbit. Fewer still have left the suns orbit.
If you go above a certain speed (escape velocity) you will indeed leave, but you’ll leave right away, not eventually.
Thank you for your response!
Pardon my crappy drawing and simplification… trying to understand…
Is that right?
But yes, there goes my self destruct notion down the drain.
There is no orbit altitude that requires more energy to maintain than a lower altitude.
Zone 1 requires more reboosting that 2, which requires more than 3, which requires more than 4. I dont know the exact relationship, (someone else might know), but we can consider it linear for simplification. The further away from earth, there will be less atmospheric drag, which means a longer stable orbit.
The travel distance doesn’t really change anything, it doesn’t affect the orbit stability.
Think of it like this spring. Your satellite can start at any point, and with no additional energy, Itll follow the path all the way down to the middle (earth). Start low, and itll reach ground quickly, start high, and itll take a lot longer. There is no energy required to stay on the spiral path. Once the sat is low enough, you may want to reboost, which is when you need to use energy to jump up to a higher point on the spiral, at which the path continues.
That spring is also a good visual to help illustrate what is meant by “gravity well”.
That image and your description helped a ton. So there isn’t a magic zone but more of a threshold after which things get easier to maintain.
Really should start playing Kerbal Space Program as someone before pointed out. You seem to have a great conceptual model of this. Thank you for engaging 🙂
Outer Wilds is much more user friendly imo. Also the fact that some planets/comets are so small you can basically run and jump at orbital speeds really helps you to conceptualize the interaction of forces.
I spent a whole cycle jumping from north pole to south pole with just my jetpack on this neat binary planet system. The gravity on them is so low you can jump off one planet, boost straight up, and fall all the way to the other planet without your ship. It’s really fun.
Not even a threshold, its a much more smooth transition, thats just the best picture I could find.
KSP will definitely help. Chuck your SATs into orbit, and you can see the orbits slowly decay away, almost imperceptibly. Its fun too :)