NASA will hold a special memorial service Saturday to honor the lives of astronauts Gus Grissom, Ed White and Roger Chaffee who died in the Apollo 1 fire.

Saturday, Jan. 27, marks the 40^th anniversary of a tragic fire that killed the Apollo 1 crew as the astronauts participated in a routine test in their spacecraft atop a launch pad at NASA’s Kennedy Space Center in Cape Canaveral, Florida. Here, the crew – from left: Grissom, White and Chaffee – stands clad in their spacesuits during mission training.

NASA will commemorate the Apollo 1 fire, which stalled the space agency’s push to the Moon until major spacecraft improvements were implemented, during a service at the Space Mirror, an astronaut memorial at the Kennedy Space Center Visitor Complex. The service begins at 10:00 a.m. EST (1500 GMT) and will be broadcast live on NASA TV. [Click here for NASA TV video.]

Walt Cunningham, a former Apollo astronaut who not only served on the Apollo 1 investigation board but also flew aboard the next manned Apollo mission – Apollo 7 – told SPACE.com that since the fire occurred on Earth, rather than in space, it gave NASA the evidence required to make necessary safety changes.

“Consequently, the flight crews benefited. We had to fix anything that was even remotely connected with it,” Cunningham said, adding that when Apollo 7 flew in October 1968 it performed nearly flawlessly. “It was the closest thing to a perfect spacecraft you that you can think of.”

NASA will also honor the lives of the seven Challenger shuttle astronauts lost on Jan. 28, 1986; the seven STS-107 astronauts who were killed aboard Columbia during their Feb. 1, 2003 landing attempt; and other NASA astronauts, employees and their Russian cosmonaut counterparts who have died in the course of space exploration.

• Chronology: A Timeline of NASA’s Apollo Program Astronaut Missions
• Spirited Salute to Fallen Apollo 1 Crew
• Top 10 Apollo Era Moon Discoveries
• Remembering Challenger: Shuttle Disaster and Others Refocus NASA
• Special Report: NASA’s Space Shuttle Fleet Celebrates 25 Years

-- Tariq Malik

Credit: NASA/JSC.