Kristy Carroll, family friend of the late space shuttle Columbia astronaut William McCool, and acting NASA Administrator Robert Lightfoot lay a wreath at the Space Shuttle Columbia Memorial as part of NASA's Day of Remembrance, Thursday, Jan. 25, 2018, at Arlington National Cemetery in Arlington, Virginia. Wreaths were laid in memory of those men and women who lost their lives in the quest for space exploration. Photo Credit: (NASA/Bill Ingalls)