What goes up
Everything that we send high enough into space will ultimately end up as space garbage. As long as an object is above the earth atmosphere it will stay in orbit for thousands or even millions of years. Some day it will hit one of the other millions of objects orbiting the earth and that will create more pieces of space garbage, which could crash into each other. For this reason, going into space is very risky and crashing into space garbage is just one of the risks.
After 40 years of sending objects into space, we have seriously polluted the final frontier. Many space paths are littered with garbage and have become a threat to satellites and astronauts.
(Extract from “Our world protecting the environment’- Andrew Bennetto & Heather Jones)
The underlined expression in ”As long as an object is above the earth atmosphere it will stay in orbit…” can, without changing the meaning, be replaced by