Study Finds Space Shuttle Exhaust Creates Night-shining Clouds

Exhaust from the main engines of NASA’s space shuttle, which is about 97 percent water vapor, can travel to the Arctic in Earth’s thermosphere, the highest part of the atmosphere, where it forms ice to create clouds that shine at night, according to a new study. The thermosphere is above 88 kilometers [55 miles] altitude. The clouds settle to around 82 kilometers [51 miles] altitude in the layer directly below, called the mesosphere. The stratosphere and the troposphere lie in that order below the mesosphere.