It’s 5 a.m. on a normal September day and #NASAExplorers have gathered in a California field to watch a rocket launch light up the pre-dawn sky. On board the rocket is a satellite more than 10 years in the making, with one single instrument that will revolutionize the study of ice on Earth. Join the team in the excitement and stress of watching ICESat-2 launch into space and begin its work measuring our home planet.