NASA astronaut Doug Wheelock leaves his STS-120 mission patch at the memorial for the Space Shuttle Challenger crew during National Wreaths Across America Day at Arlington National Cemetery, Sat., Dec. 14, 2019 in Arlington, Va. National Wreaths Across America Day is held annually to celebrate the lives of military veterans and wreaths are placed at the foot of every headstone. Wheelock honored those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)