Northrop Grumman's L-1011 Stargazer prepares for takeoff June 6, 2018, from the hot pad at Vandenberg Air Force Base in California. The company's Pegasus XL rocket, containing NASA's Ionospheric Connection Explorer (ICON), is attached beneath the aircraft. The explorer will launch on June 15, 2018, from Kwajalein Atoll in the Marshall Islands (June 14 in the continental United States). ICON will study the frontier of space - the dynamic zone high in Earth's atmosphere where terrestrial weather from below meets space weather above. The explorer will help determine the physics of Earth's space environment and pave the way for mitigating its effects on our technology, communications systems and society.