Hi,

During the launch of a Titan IV B-30 Rocket from Vandenburg AFB in California on 30 April 2005, 171 metric tons (171, 000 kg) of fuel and oxidizer were exhausted at heights that correspond to Earth’s ionosphere (75-500 km). These exhaust gases typically produce heavy hydrogen (H2), water (H2O), and Carbon Dioxide (CO2), Water and carbon dioxide make up small amounts of the regular atmospheric mixture. it is the extra amounts of these chemicals in exhaust plumes at great heights that make them unusual.

Further, these chemicals change the balance of ions in the ionosphere, resulting significant decreases in the usual amount of ionization (electrons separated from their parent ions and molecules). The result is a large area of rocket exhaust depletions (REDS) that can last for hours. The sharp changes in ionization at the edge of the depletions can affect Global Position System signals.

The answer above only addresses a small part of the question, but it is a start. You should also know that the rocket bodies that deliver instruments and satellites to space are also often left in space, creating a population of debris that operating spacecraft have to dodge.

Hello JB!

Debris from old satellites and rockets orbiting the Earth is a serious problem, sort of like in the film Gravity. Satellites that I have worked on have had collisions with unknown space debris or micrometeorites that caused damage to the scientific instruments. Once in a while, satellites need to perform maneuvers to avoid collisions with known space debris. Space debris also poses a risk to the International Space Station and the astronauts on board. The United States tracks thousands of man-made objects, including working satellites, orbiting around the Earth, but there are even thousands more pieces of space debris that are far too small to be tracked. To prevent the amount of pollution in space from increasing to extremely high levels like in the film Gravity, the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) has created guidelines for preventing collisions and reducing space debris. The U.S. has also developed its own standard space debris mitigation practices for NASA and the military. So has the European Space Agency. When satellites orbiting the Earth reach the end of their useful lifetimes, they sometimes are placed into "graveyard" orbits where the chances of colliding with other satellites are smaller. Many satellites have plans for controlled de-orbiting so that they safely disintegrate upon re-entering Earth's atmosphere, over the ocean, away from populated areas. Scientists and engineers have also proposed methods of re-fueling and repairing satellites in orbit to extend their lifetimes, as well as methods to clean up space debris, but these things are far into the future.