Where does outer space begin?

Print Friendly and PDF
Where does outer space begin?
There is no defined border between atmosphere and outer space. With constant changing temperatures (decreasing and increasing), the atmosphere finally peters out into the solar wind. Were it not for the atmosphere, a satellite orbit could be achieved almost skimming the surface of the earth. However, the friction with the atmosphere would terminate the mission quickly. To avoid friction with the atmosphere a satellite must have a minimum altitude of about 100 miles to be in orbit.