It's going to take a lot of fuel to get to Mars. This month engineers at NASA finished the last of the welding that completed this giant liquid oxygen tank--part of NASA's new Space Launch System--which together with another tank that will store hydrogen, it will help power RS-25 engines. NASA/Michoud/Steven Seipel
is the Science Editor at Popular Science. She has a particular interest in brain science, the microbiome, and human physiology. In addition to Popular Science, her work has appeared in The New York Times, Scientific American, and Scholastic’s Science World and Super Science magazines, among others. She has a bachelor’s degree in neurobiology from the University of California, Davis and a master’s in science journalism from New York University's Science, Health, and Environmental Reporting Program. Contact the author here.