A visitor wraps ribbon around a wreath before laying it at a headstone on 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. NASA astronaut Doug Wheelock attended to honor those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)

Visitors stop to look at the headstone of former astronaut and U.S. Senator John Glenn on 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. NASA astronaut Doug Wheelock attended to honor those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Doug Wheelock lays a wreath at the grave marker of Virgil "Gus" Grissom from Apollo 1 as part of National Wreaths Across America Day, Sat., Dec. 14, 2019 at Arlington National Cemetery 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)

NASA astronaut Doug Wheelock lays a wreath at the grave marker of Roger Chaffee from Apollo 1 as part of National Wreaths Across America Day, Sat., Dec. 14, 2019 at Arlington National Cemetery 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)

NASA astronaut Doug Wheelock lays a wreath at the gravesite of former astronaut and U.S. Senator John Glenn 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)

The grave markers of Virgil "Gus" Grissom and Roger Chaffee, from Apollo 1, are seen after NASA astronaut Doug Wheelock laid wreaths at each site as part of National Wreaths Across America Day, Sat., Dec. 14, 2019 at Arlington National Cemetery 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)

Items are seen on top of the headstone of former astronaut and U.S. Senator John Glenn on 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. NASA astronaut Doug Wheelock attended to honor those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)

Items are seen at the Space Shuttle Challenger memorial on 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. NASA astronaut Doug Wheelock attended to honor those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)

Items are seen at the Space Shuttle Challenger memorial on 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. NASA astronaut Doug Wheelock attended to honor those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)

The headstone of former astronaut and U.S. Senator John Glenn is seen on 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. NASA astronaut Doug Wheelock attended to honor those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)

On National Wreaths Across America Day, items are seen on top of the headstone of the Extortion 17, service members who lost their lives during a tour of duty in Afghanistan, Sat., Dec. 14, 2019 at Arlington National Cemetery in Arlington, Va. National Wreaths Across America Day is held annually to celebrate the lives of military veterans. NASA astronaut Doug Wheelock served with the Extortion 17 and honored them as well as those who lost their lives in the quest for space exploration by laying wreaths at their headstones and at the memorial sites. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Doug Wheelock takes a moment after laying a wreath at the headstone of the Extortion 17, fellow service members who lost their lives during his tour of duty in Afghanistan, as part of National Wreaths Across America Day, Sat., Dec. 14, 2019 at Arlington National Cemetery in Arlington, Va. National Wreaths Across America Day is held annually to celebrate the lives of military veterans. Wheelock honored those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Doug Wheelock lays a wreath 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)

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)

NASA astronaut Doug Wheelock takes a moment after leaving his STS-120 mission patch at the memorial for the Space Shuttle Columbia 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)

NASA astronaut Doug Wheelock leaves his STS-120 mission patch at the gravesite of former astronaut and U.S. Senator John Glenn 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)

NASA astronaut Doug Wheelock leaves a NASA pin on the headstone of the Extortion 17, fellow service members who lost their lives during his tour of duty in Afghanistan, as part of National Wreaths Across America Day, Sat., Dec. 14, 2019 at Arlington National Cemetery in Arlington, Va. National Wreaths Across America Day is held annually to celebrate the lives of military veterans. Wheelock honored those who lost their lives in the quest for space exploration as well as fellow service members. Photo Credit: (NASA/Aubrey Gemignani)