Some negative consequences of space exploration include the emission of ozone-depleting substances and the presence of man-made debris in the earth's orbit. In addition, astronauts may experience some negative physical effects of space exploration.
Space exploration can have a negative impact on the environment. When rockets launch into space, their engines let out gases and debris such as aluminum oxide and soot. These substances can damage the ozone layer and contribute to global warming.
However, space travel is not nearly as commonplace as car or airplane travel, which also release harmful substances into the atmosphere. Therefore, space exploration does significantly contribute to global warming. As space exploration becomes more commonplace, scientists must tackle environmental issues associated with rocket launches.
In addition to gases and particles, man-made objects often get left behind in the earth's orbit. There are over 500,000 pieces of orbital debris in orbit, according to NASA. Orbital debris includes broken spacecraft, pieces of launch vehicles, pieces of spacecraft and satellites that break off during explosions, pieces of paint and used batteries. Orbital debris does not significantly affect the earth itself, but it does pose a small risk to astronauts working in space. The U.S. and other countries such as Russia and China have guidelines in place to reduce orbital debris.
Space exploration can have negative health consequences to astronauts. Zero gravity conditions can cause bones to release less calcium, causing them to become brittle. Radiation can also impact bones. Floating also causes back and lower body muscles to become weaker, as they are not used in the same way.
In addition, space exploration can cause changes to the body's balance system and inner clock. Astronauts must undergo a period of adjustment after returning to Earth.