Apollo 1 was an ill-fated mission in which all three of the astronauts died in a fire in the capsule during a pre-launch test for the first manned Apollo mission. It was one of NASA's darkest hours.

Gus Grissom: In 1957 Grissom received a "Top Secret" invitation, along with 109 other test pilots, to try out for Project Mercury. On April 13, 1959, he was notified that he had been chosen as one of the seven Mercury astronauts.

On July 21, 1961, Grissom was pilot of the second Project Mercury flight popularly known as Liberty Bell 7. This was a suborbital flight which lasted 15 minutes and 37 seconds. After splashdown, emergency explosive bolts unexpectedly fired and blew the hatch off, causing water to flood into the spacecraft. Quickly exiting through the open hatch and into the ocean, Grissom was nearly drowned as water began filling his spacesuit. A recovery helicopter tried to lift and recover the spacecraft, but the flooding spacecraft became too heavy, and it was ultimately cut loose before sinking. Grissom asserted he had done nothing to cause the hatch to blow, and NASA officials eventually concluded that he was correct.

Grissom's spacecraft was recovered in 1999, but no further evidence was found which could conclusively explain how the explosive hatch release had occurred. Grissom later flew on Gemini 3, the first manned Project Gemini flight, which went up on March 23, 1965. This mission made him the first NASA astronaut to fly into space twice.

In a joking nod to the sinking of his Mercury craft Grissom named the first Gemini spacecraft Molly Brown after the popular Broadway show The Unsinkable Molly Brown; NASA publicity officials were unhappy with this name. When Grissom and his pilot John Young were ordered to come up with a new one, they offered Titanic. Aghast, NASA executives gave in and allowed the name Molly Brown, but did not use it in any official references. Subsequently and much to the agency's chagrin, on launch CAPCOM Gordon Cooper gave Gemini 3 its sendoff by saying over the uplink, "You're on your way, Molly Brown!" and ground controllers used this name throughout the flight.

Grissom was shifted to the Apollo program and was assigned as Command Pilot of the first manned mission AS-204 mission (later renamed to Apollo 1 by it's 3 astronaut crew members). Died in the Apollo 1 fire on January 27, 1967 aged 40.

Ed White: On June 3, 1965, he became the first American to "walk" in space while on the Gemini 4 mission. He found the experience so exhilarating that he was reluctant to terminate the EVA at the allotted time, and had to be ordered back into the spacecraft.

While he was outside, a spare thermal glove floated away through the open hatch of the spacecraft, becoming an early piece of space debris in low-earth orbit, until it burned up upon re-entry into the Earth's atmosphere. Died in the Apollo 1 fire on January 27, 1967 aged 36.

Roger Chaffee: Rose to the rank of Lieutenant Commander in the Navy. He got his aviator wings in 1959 and was accepted into the initial pool of 1,800 applicants for the third group of NASA astronauts in mid 1962.

Chaffee was an avid hunter. After completing the astronaut application process, he went hunting to calm his nerves. It was while he was on that hunting trip that NASA called him to offer him an astronaut slot.

He never got a seat on a Gemini mission, but was tasked with working on flight control, communications, instrumentation, and attitude and translation control systems in the Apollo program. On 21 March 1966, he received his first spaceflight assignment as Pilot for the first manned Apollo flight, AS-204, along with Command Pilot Gus Grissom and Senior Pilot Ed White. In June 1966, the men got permission to name their flight Apollo 1. He died in the Apollo 1 fire on January 27, 1967 aged 31.