Old satellites can end up in a few different places when they reach the end of their operational lifetime:
Decayed orbit: If the satellite is in a low Earth orbit, atmospheric drag will eventually cause it to lose altitude and burn up in the upper atmosphere. This leaves no debris behind.
Graveyard orbit: Satellites in higher orbits like GEO may be boosted into a slightly higher “graveyard” orbit to free up their operational orbit. They remain in this orbit indefinitely.
Direct re-entry: Some satellites, especially in LEO, may do a controlled re-entry to deliberately burn up in the atmosphere and not leave space debris.
Space junk: If not disposed of properly, dead satellites can become space debris. This refers to any defunct man-made object in orbit, including old spacecraft and parts like spent rocket stages. Space junk can remain in orbit for a long time.
Deep space: Most become deep space junk once their mission is complete. A few special cases like Hayabusa’s return capsule, deliberately perform a controlled return, and reentry for recovery, to Earth from deep space.
So in summary, low Earth orbit satellites usually decay and burn up, while higher satellites go into graveyard orbits or, if uncontrolled, add to the space junk problem. Proper disposal procedures help minimize space debris.
