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!
Maintaining geosynchronous orbit does require maintenance because there’s still a non-trivial amount of air resistance that will slowly decrease speed and de-orbit the satellite.
With a bit more detail: there is a specific altitude and speed that an object must maintain in order to stay in orbit above a fixed point above the earth. Earth’s mass, and thus its gravitational pull, dictate this speed and altitude through physics. There are other speeds and attitudes that can achieve the same effect (geosynchronous orbit) but they require propulsion to maintain. With the Earth, that “sweet spot” where you can achieve the correct orbital velocity to keep a geosynchronous orbit is still within the atmosphere, albeit very thin, so friction with the air slowly makes satellites lose speed. An orbit is based on speed (speed up and you get farther away from the planet, slow down and you draw closer to the planet) so as the satellites slow down they have to periodically “boost up” or eventually their orbit will decay and they’ll re-enter and burn up.
Self destruct? Not a good idea. Controlled re-entry is essentially self destruct.
More space junk from just a random explosion is really bad. Space junk is really bad. If it gets bad enough it can potentially have a cascading effect where space junk collides with other stuff and causes more space junk and explosions, starting a chain reaction that creates a scatter field of junk that traps us on the planet. The concept is known as Kessler Syndrome.
https://en.m.wikipedia.org/wiki/Kessler_syndrome
Thank you so much for the detailed response. That Kessler syndrome is scary…
So the best method is a controlled reentry. From the wikipedia link, I’m now inspired to replace the self destruct button to a megawatt laser for dealing with debris.