NASA Launch Director Charlie Blackwell-Thompson, at left, arrives at Launch Pad 39B at NASA's Kennedy Space Center in Florida, to observe the first major tanking operation of liquid oxygen, or LO2, into the giant storage sphere at the northwest corner of the pad to prepare for the launch of the agency's Orion spacecraft atop the Space Launch System (SLS) rocket. During the operation, several Praxair trucks will slowly offload LO2 to gradually chill down the sphere from normal temperature to about negative 298 degrees Fahrenheit. The Ground Systems Development and Operations Program is overseeing upgrades and modifications to pad B to support the launch of the SLS and Orion spacecraft for Exploration Mission-1, deep space missions and NASA’s journey to Mars.