Every year, NASA recognizes astronauts who lost their lives in the pursuit of spaceflight with an official Day of Remembrance. This year, it’s celebrated Feb. 7. And NASA Administrator Jim Bridenstine will lay a wreath at the Tomb of the Unknown Soldier in Arlington National Cemetery. Another wreath-laying ceremony will also happen at Kennedy Space Center’s Space Mirror Memorial. Both ceremonies will also include observances for NASA’s lost explorers.

The three great disasters in NASA his