NASA Administrator Jim Bridenstine speaks to family members and friends of astronauts lost in the Challenger and Columbia missions during a wreath laying ceremony as part of NASA's Day of Remembrance, Thursday, Feb. 7, 2019, at Arlington National Cemetery in Arlington, Va. The wreaths were laid in memory of those men and women who lost their lives in the quest for space exploration. Photo Credit: (NASA/Aubrey Gemignani)

Vice President Mike Pence observes the grave marker of Virgil "Gus" Grissom, from Apollo 1, after family and friends of astronauts lost in the Challenger and Columbia missions, former NASA Administrators, and other NASA staff participated in a wreath laying ceremony that was part of NASA's Day of Remembrance, Thursday, Feb. 7, 2019, at Arlington National Cemetery in Arlington, Va. Wreaths were laid in memory of those men and women who lost their lives in the quest for space exploration. Photo Credit: (NASA/Aubrey Gemignani)