The #EarthExpedition Atmospheric Tomography (ATom) mission has set off on its final around-the-world science flights. Numerous instruments aboard NASA's DC-8 flying laboratory will be taking measurements as the science team flies down the Pacific Ocean from Alaska to the southern tip of South America, then north up the Atlantic to Greenland to measure more than 400 gases and particles in the air and their interactions around the world. ATom’s flights will help us better understand how short-live