NASA held its annual Day of Remembrance on Wednesday to pay tribute to the astronauts who lost their lives in missions aimed at exploring outer space.
Among the honored astronauts were the three crewmembers who were killed in the Apollo 1 fire in 1967, the seven crewmembers who died in the Challenger space shuttle explosion in 1986 and the seven crewmembers lost during the Space Shuttle Columbia's destruction in 2003, according to The Christian Science Monitor.
The Apollo 1 fire took place on Jan. 27, 1967 at Florida's Cape Canaveral Air Force Station during a pre-launch test, resulting in the deaths of astronauts Gus Grissom, Ed White and Roger Chaffee.
Wednesday also marked the 29th anniversary of the Challenger explosion, which was caused by a failure in the boost engine, CBS News reported. The shuttle broke apart in midair only 73 seconds after launch.
The Space Shuttle Columbia broke apart on Feb. 1, 2003 upon re-entry from space and burst into flames, resulting in the deaths of its seven crew members only 16 minutes before they were about to return home.
"Today we remember and gives thanks for the lives and contributions of those who gave all trying to push the boundaries of human achievement," NASA administrator Charles Bolden said in a statement, CBS News reported. "On this solemn occasion, we pause in our normal routines and remember the STS-107 Columbia crew; the STS-51L Challenger crew; the Apollo 1 crew; Mike Adams, the first in-flight fatality of the space program as he piloted the X-15 No.3 on a research flight; and those lost in test flights and aeronautics research throughout our history."
Those killed in the Challenger explosion include Francis "Dick" Scobee, Ronald McNair, Mike Smith, Ellison Onizuka, Judy Resnik, Greg Jarvis and Christa McAuliffe, who was going to be the first teach in space, The Christian Science Monitor reported. Those who lost their lives in the Columbia incident were Rick Husband, Willie McCool, Kalpana Chawla, Laurel Clark, David Brown, Michael Anderson and Ilan Ramon, who was Israel's first astronaut.
Officials said different NASA centers also held their own observances, including a brief ceremony at the Kennedy Space Center in Florida and a candle-lighting ceremony at the Marshall Space Flight Center in Alabama.
Others who paid tribute to those who gave their lives for space exploration include European Space Agency astronaut Sam Cristoforetti, who paid her respects with a message on Twitter on Tuesday, Jan, 27, The Christian Science Monitor reported.
"May the memory of such a dark time in our past enlighten the future with wisdom and compassion. ?#RemembranceDay," Cristoforetti wrote.
