On the afternoon of January 27, 1967, the three crew members of the first Apollo mission left the transfer van that took them to the launch pad at Cape Canaveral. There, astronauts Roger Chaffee, Gus Grissom, and Ed White entered the command module and began a “plugs out” test (that is, with the spacecraft detached from all umbilicals and external power sources) of the launch vehicle and spacecraft designed to carry them on their mission.At 6:31 p.m., a spark ignited in the lower equipment bay of the spacecraft. The atmosphere inside was 100 percent oxygen. The astronauts didn’t have a...…On the afternoon of January 27, 1967, the three crew members of the first Apollo mission left the transfer van that took them to the launch pad at Cape Canaveral. There, astronauts Roger Chaffee, Gus Grissom, and Ed White entered the command module and began a “plugs out” test (that is, with the spacecraft detached from all umbilicals and external power sources) of the launch vehicle and spacecraft designed to carry them on their mission.At 6:31 p.m., a spark ignited in the lower equipment bay of the spacecraft. The atmosphere inside was 100 percent oxygen. The astronauts didn’t have a...WW…