In 2007, NASA launched the Aeronomy of Ice in the Mesosphere (AIM) project to study noctilucent clouds, often known as night-shining clouds or fossilised clouds since they can persist for hundreds of years in Earth’s upper atmosphere. With data collected by AIM appearing in 379 peer-reviewed papers, including a recent 2018 study that found methane emissions from human-driven climate change are causing night-shining clouds to form more frequently, the spacecraft proved invaluable to scientists from its vantage point 370 miles above the planet’s surface. Pretty good for a mission that NASA had originally anticipated lasting only two years. The demise of AIM comes after that of another veteran NASA spacecraft. After nearly four decades of gathering ozone and atmospheric observations, the NASA deorbited the Earth Radiation Budget Satellite at the beginning of the year.
