Samples of water, filled with green dye, gathered from two water tanks that have spent the past five years in space, are photographed inside the Neil Armstrong Operations and Checkout Building at NASA’s Kennedy Space Center in Florida on Nov. 13, 2019. The tanks were first sent to the International Space Station in 2014 to study slosh, or the movement of water, in a zero-gravity environment to help engineers predict the movement of propellant in rocket tanks. With the slosh experiment now concluded and the tanks recently returned to Kennedy, they are being utilized for a biological study to determine if there is, or was, any microbial growth within them. The results will help NASA determine whether clean water can be stored in space for long-duration missions, an essential component to keeping astronauts safe and healthy as the agency prepares for missions to the Moon and beyond to Mars.