What are defunct satellites?

Defunct satellites are old space machines that no longer work and just float around Earth like tiny, silent rocks.

Imagine your favorite toy robot. It runs on batteries or a solar panel that catches sunlight. When the batteries run out or the solar panel breaks, the robot stops moving. Defunct satellites are exactly like that toy. They have used up all their fuel or their electronics have failed. They cannot talk to people on Earth anymore. They cannot take pictures or send internet signals. They are simply retired from their job.

Once a satellite stops working, it becomes space junk. Think of it like a leaf that has fallen off a tree. It does not go anywhere; it just drifts. Because there is no air in space to slow things down, these dead satellites keep flying around Earth for a very long time. Some might eventually fall into the atmosphere and burn up like a firework. Others stay up there, bumping into other pieces of trash. We have to be careful because these silent travelers can crash into working satellites, just like a ball hitting other balls in a box. They are the ghosts of space exploration.