On Thursday, NASA honored all astronauts who have lost their lives in the name of space exploration, 35 years to the day after seven astronauts were killed in the Challenger space shuttle disaster.
On Jan. 28, 1986, the seven astronauts aboard the Challenger died when the space shuttle exploded 73 seconds after liftoff from the Kennedy Space Center.
Among those killed was Christa McAuliffe, a schoolteacher who was set to become the first civilian sent to outer space by NASA. Her involvement in the mission tragically meant the disaster was broadcast live in schools across the country.
The other six astronauts killed in the explosion were Commander Francis Scobee, pilot Michael Smith, mission specialist Ronald McNair, mission specialist Ellison Onizuka, missions specialist Judith Resnik and payload specialist Gregory Jarvis.
The Challenger mission remains tied for the deadliest space-related mission in world history. In 2003, seven astronauts were also killed when the space shuttle Columbia broke up upon re-entry into the Earth's atmosphere.
On Thursday, NASA held a ceremony of remembrance at Kennedy Space Center in Cape Canaveral, Florida to honor all those killed in space missions during the agency's 62-year history, including the seven astronauts killed in the Challenger explosion.