A solar array illumination test is performed on NASA's Ionospheric Connection Explorer (ICON) in a clean room inside Building 1555 at Vandenberg Air Force Base in California on May 4, 2018. The test checks for any imperfections and confirms that the solar arrays are functioning properly. The explorer will launch on June 15, 2018, from Kwajalein Atoll in the Marshall Islands (June 14 in the continental United States) on Orbital ATK's Pegasus XL rocket, which is attached to the company's L-1011 Stargazer aircraft. 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.