NASA astronaut Joe Acaba, right, shakes hands with Lieutenant Colonel Jeffery Todd Burroughs, battalion commander, Old Guard, Friday, June 15, 2018 at the Arlington National Cemetery in Arlington, Va. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronauts Mark Vande Hei, center, and Joe Acaba, right, present Lieutenant Colonel Jeffery Todd Burroughs, battalion commander, Old Guard, and others from the Honor Guard with their patch that was flown onboard the International Space Station during Expedition 54, Friday, June 15, 2018 at the Arlington National Cemetery in Arlington, Va. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronauts Mark Vande Hei, third from left, and Joe Acaba, third from right, meet with the Honor Guard at the Tomb of the Unknowns, Friday, June 15, 2018 at the Arlington National Cemetery in Arlington, Va. Photo Credit: (NASA/Aubrey Gemignani)