Fifty years ago today, the United States space program suffered a tragic setback that almost cost America the Space Race. During a routine training exercise leading up to what was supposed to be the first manned Apollo mission, a Command Module suffered a terrifying flash fire that took the lives of the three astronauts on board and revealed a frightening list of shortcomings in NASA's quest to be first on the Moon.

In January 1967, NASA was riding high. The Space Race between the United States and the Soviet Union was at its peak and despite a series of failures, the space agency's policy of making each manned mission an exercise in mastering spaceflight instead of the Soviet racking up firsts for firsts' sake was paying off, and contractors seemed like they were creating new manned spacecraft designs as fast as Detroit was new car models.

With the end of Project Gemini, NASA was now poised for its greatest conquest: The Moon. Mercury had proven that astronauts could live and work in space and the two-man Gemini missions acted as practice for the skills needed to carry out lunar landings. But the next step was Apollo, which was a quantum leap beyond anything yet attempted in space. This would not only include a three-man capsule, but would be the first true spaceship capable of journeying into deep space and back again.

Apollo 1 crew in a simulator(Credit: NASA)

The first mission was what came to be known as Apollo 1, though, at the time, its official designation was AS-204. "AS" stood for Apollo Saturn and included the Apollo Command Module, the Service Module, and the fourth of the Saturn 1B boosters – the smaller sibling of the Saturn V that was still under development. The Saturn 1B, on the other hand, was designed to carry Apollo into low Earth orbit.

Scheduled to fly on February 21, 1967, the goal of Apollo 1 was simple. The three astronauts were to take the Command Service Module (CSM) into orbit for an initial test flight to see how well its systems performed and to help engineers refine the final design for the Moon missions.

The primary crew of Apollo one was made up of two space veterans and a rookie. The Commander was 40-year-old USAF Lieutenant Colonel Virgil Ivan "Gus" Grissom, who was selected for astronaut training in 1960 and was the pilot on the one-man Mercury Redstone 4 mission in 1961 – the second and last of NASA's suborbital Mercury flights. He went on to become Command Pilot for Gemini 3 in 1965 with John Young as Pilot.

The second member of the crew was USAF Lieutenant Colonel Edward Higgins White II, who acted as Senior Pilot. Born on November 14, 1930 in San Antonio, Texas, the 36-year-old White was the Pilot for the Gemini 4 mission in 1965 with Command Pilot James McDivitt. White was justly famous as the first American to walk in space and was assigned the post of Senior Pilot for Apollo 1.

Making up the complement was USN Lieutenant Commander Roger Bruce Chaffee, who was assigned the position of Pilot. The only member not to fly in space, he was 31-years old and had been selected as an astronaut in 1963.

Their craft was the unromantically named Command Module CM-012. Built by North American Aviation starting in 1964, it was a Block 1 module, which means it was simpler in design from the later Block 2 spacecraft. This was because much of the Moon landing program was still in the planning phase, so there were many blanks to fill in, like a docking mechanism that had yet to be decided on. However, it was slated to be the first mission to carry a television camera for live broadcasts from inside the Command Module using a TV camera. This was not only good PR, but also a way for mission control to monitor cabin instruments directly.

One very important feature of Apollo 1 was that, like Mercury and Gemini, the life support system would use pure oxygen in the Command Module instead of normal air. Since Mercury, NASA had opted for using pure oxygen at a cabin pressure of 5 psi because this made it easier to design the capsule and make it lighter. It also reduced the risk of the bends because the astronauts would have very little nitrogen in their bloodstream and body tissues, and it eliminated the risk of a spacesuit suddenly flooding with pure nitrogen and suffocating the wearer.

But that didn't seem to matter on January 27, 1967. By this time, the Command Module had completed an uneventful series of tests and rehearsals, including dry runs inside of NASA's low-pressure chamber and the spacecraft had recently been mated with the Service Module and hoisted atop the unfueled Saturn 1B booster at Launch Complex 34 at Cape Kennedy, Florida.

That Friday beginning at 7:55 am EST (12:55 GMT), the astronauts and ground crew started another in a long series of routine tests to rehearse the space travelers for the February flight and certify the capsule as space worthy. The capsule was surrounded by the gantry test chamber called the White Room to protect it from the elements and the spacecraft was configured for a "Plugs-Out Integrated Test," which meant that the capsule was on internal power and configured as close as possible to what it would be in flight.

At 1:00 pm (18:00 GMT), the astronauts entered the Command Module and their space suits sealed and connected to the life support and communications systems. After a brief hold when Grissom reported a smell like sour milk, the go ahead was given and the hatches were sealed at 2:42 pm. The cabin was then purged with pure oxygen at 5 psi above normal air pressure to simulate space conditions.

Things were still routine at this point, with the only glitches being a microphone stuck open and problems communicating with ground control. The astronauts and technicians worked to isolate the fault and at 3:20 pm the simulated countdown was put on hold until communications could be fixed. In the meantime, all other systems were reading normal aside from the guidance system detecting some crew movement inside the capsule, but the life readings gave no sign of any sort of problem.

Then at 3:31 pm everything went horribly wrong. The crew reported that there was a fire in the capsule, saying "We've got a bad fire – let's get out. We're burning up.''

Within seconds, a fire that broke out in the lower left area of the Command Module spread with terrifying speed. Grissom was forced to abandon his couch while White struggled to open the hatch. The flames shot to the ceiling and molten nylon firebrands spread the flames even faster.

To have some idea of the speed of what was happening, think back to demonstrations about oxygen that you may have seen in school. One common experiment is to fill a jar with pure oxygen and add a piece of burning steel wool. In normal air, the burning pad simply smolders with red sparks, but once dipped in the jar, it bursts into a white-flame and is consumed almost immediately.

That is what was happening in Apollo 1 as fabric, plastic, and even metal burned at incredible speed. In seconds, the temperature in the capsule reached 1,640⁰ K (2,500⁰ F/1,371⁰ C) and the interior pressure doubled in 12 seconds.

Outside the capsule, the ground crew were already rushing to rescue the three trapped astronauts, who couldn't open the hatch from the inside because of the interior pressure holding it shut. Suddenly, the capsule itself ruptured. Hot gases blasted out, starting secondary fires and air rushed in to turn the interior into a smoky inferno. By this time, less than 20 seconds since the first alarm, all communications with the astronauts were lost.

As air pressure dropped to normal in the capsule, smoke started to billow out into the White Room. The technicians retreated for a few seconds, fearing that the capsule or the spacecraft's solid rocket escape motor was about to explode. They returned with breathing masks, fire extinguishers and special tools to open the hatches.

The Block 1 Command Module was equipped with three hatches: An inner pressure hatch that opened inward, a second other hatch that opened outward, and a plastic fairing hatch designed to protect the other hatches during lift off. Under ideal conditions, it would have taken 90 seconds to remove the three hatches, but these were far from normal conditions. The ground crew could barely see in the smoke and their breathing masks, those they could get working, were designed to handle fuel leaks, not smoke, so the crew had to take it in turns as others sought fresh air.

Five minutes after the fire was reported, the hatches were opened and the rescuers were greeted by a blast of intense heat and smoke. At 3:40 pm, the first firefighting crew arrived and doctors arrived at 3:43 pm. Inside the Command Module, Grissom, White, and Chaffee were dead. Though their spacesuits were charred and their bodies suffered extensive third degree burns, autopsies later revealed that they had expired quickly and painless when their suits had failed in the first blast of flame, melting their air hoses and flooding their bloodstreams with carbon monoxide, causing their hearts to stop.

Now came the terrible and vitally important business of finding out exactly what had happened. Nothing could be touched until a complete examination could be made and evidence recorded.

In light of this, sentiment went out the window. Since the astronauts' spacesuits were welded to the capsule by the melting of their nylon fabric, the doctors decided not to move the bodies for seven hours while investigators took careful photographs with special emphasis on the control boards to see which switches were in which positions.

Meanwhile, Launch Complex 34 was sealed off and security personnel posted. Once the crew was removed and photographs were taken of the capsule's exterior and interior, the Command Module was unshipped from the booster and sent to the Kennedy Space Center. There it and an identical Block 1 module for comparison were dismantled piece by piece, each fragment inspected, photographed before, during, and after removal, then carefully cataloged and stored. A special false plastic floor was installed in the capsule to allow workers to move about without disturbing evidence.

To interpret the evidence, a Review Board made up of 21 working panels was convened. The committee was heavily loaded with NASA personnel because of the complexity of the incident and insufficient expertise outside of the space agency for such an unprecedented accident. In addition, the director of NASA argued that the credibility of the space agency was at stake and had to be maintained.

Though the exact cause of the fire was never found, the Board came to a series of conclusions that did not reflect well on NASA or its contractors.

The CM being disassembled while a guard watches(Credit: NASA)

The main culprit in the disaster was using pure oxygen in the cabin. NASA chose it, in part, for safety reasons and it was safe in space with an absolute pressure of 5 psi, but on Earth at up to 19 psi, it turned the Command Module into an inferno waiting to happen. NASA never considered that relative pressure is different from absolute when it comes to fire.

Another problem was that the company that built the module has been lax in its design and construction, and this laxness was apparent right up to the fire. The capsule was loaded with combustible materials – especially fabric and Velcro. Fabric ties were used to bundle wiring and Velcro ties were used everywhere to secure equipment – a bad habit left over from Gemini when astronauts liked to customize their cabins.

Other problems included wiring that was poorly chosen and was vulnerable to bending and chafing. The same was true of plumbing carrying flammable liquids. In addition, there was no way for the crew to escape and they had no fire fighting equipment beyond the water hose in the galley.

Outside the capsule, there was the ground crew, who, though well trained in many respects, weren't trained to handle fires and didn't have proper fire fighting kit, breathing gear, or medical equipment. In addition, quality control was poor with poor testing procedures, modifications to designs and changes in procedures being requested and okayed verbally without proper recording or review, and inadequate safety checks.

In an interview with Air & Space Smithsonian, former Apollo 11 astronaut Michael Collins said, "Given the sophistication of NASA, given the intelligence of its engineers, given the keen, in-depth analysis that they applied to various problems, it's just amazing that the most simple, elementary things in the world are what bit them. I mean, 16 psi (sic) of pure oxygen on the pad, and just not considering that to be a tinderbox. Putting a hatch on with about 28 goddamn [latches], where you couldn't get it off!… And all of this just, somehow, I don't know why, we're blind to them. I mean, it makes us think that the quality of our engineering across the board was juvenile, yet it wasn't! It was very good engineering."

And that was part of the problem. NASA was doing very good engineering, but the engineers became so mesmerized by the progress they were making and the imperative of putting a man on the Moon that they became blind to what was obvious in hindsight. Up until Apollo 1, NASA had lost only three astronauts, and all of them on jet training flights. As to oxygen, it had worked fine on Mercury and Gemini, which induced a false sense of security.

Three men had died on Apollo 1, but another casualty could have been the entire Moon program. The Apollo program cost over US$25 billion in 1970 dollars, which is enough to finance a small war and the US was already embroiled in an expensive conflict in Indochina.

Though today the Moon landing were considered one of history's great achievements, at the time, it was very unpopular with a large segment of the American public and the Soviets were only too ready to exploit any excuse through their front groups and agents of influence in the West to push for the US to abandon the Space Race in Moscow's favor. Such an accident stood a good chance of killing Apollo.

In addition to the Review Board, the Apollo 1 investigation was subject to oversight by committees from both houses of Congress with the Senate launching its own hearings and investigations. At the least, it seemed as if the Moon landings could be tied up in Washington and delayed for several years.

However, there were other factors at work aside from the imperatives of the Cold War. The Apollo program was a key policy of the administration of President Lyndon Johnson, who was the original advocate of the project and recommended it to President Kennedy when Johnson was Vice President.

In addition to this personal stake, Johnson had used Apollo as an excuse to undertake a massive industrialization of the US Southern states, which is why there's not only a spaceport in Florida, but a space center in Texas, rocket works in Alabama, and other facilities dotted across the region. Not only was Apollo at stake, but a large part of Johnson's Great Society ambitions.

That was significant financial and political capital and the President ended up as Apollo's staunchest defender. This was fortunate because NASA manager Joe Shea was never the same after Apollo 1. He blamed himself for the disaster and recalled that after crew complaints about the Command Module he'd offered to sit in the capsule with the astronauts on the day of the test and would have, had a communication link been rigged. Instead, he ended up with a bad case of survivor's guilt and sank into depression and alcoholism until he was eased quietly out of the agency.

The crew of Apollo 1 on an earlier test(Credit: NASA)

As to Apollo, the Command Module was ordered through an extensive re-engineering. The Block 1 was immediately retired and the next batch of capsules were redesigned to eliminate channels through which fire could travel, fabrics and other combustibles were removed, wiring and plumbing systems were redesigned, and aluminum was swapped out for stainless steel in many places.

Better insulation was put in, plastic switches were replaced with metal ones, emergency breathing systems for astronauts were installed and there were fire extinguishers in cabin. Also, the old hatch was replaced with a single, quick operating hatch that opens outward and from inside in under ten seconds.

In addition, contractor procedures were reexamined, ground crews were better trained and equipped for handling fires, and it was decided that no flights were to be resumed until the astronauts themselves were confident in the spacecraft.

Apollo 1 crew in spacesuits(Credit: NASA)

As to oxygen, there was no more 100 percent oxygen during tests. Instead, normal air was used in cabin while oxygen was used in suits during ground tests. In flight, cabin air would be normal and replaced gradually during launch phase as cabin pressure was reduced. And, perhaps to keep anyone from flying in a jinxed ship, the Saturn 1B launcher atop which the fire took place was reassigned to carry the first Lunar Module in an unmanned test flight.

The lessons of Apollo 1 were deep and far reaching. In the wake of the fire and subsequent investigation, spaceflight became safer, but it also highlighted how dangerous it is. After Apollo 1, Neil Armstrong and Buzz Aldrin were all too aware that they only had a 50/50 chance of leaving the Moon alive and President Richard Nixon had a contingency speech on hand in case the worst happened.

In the decades after, there have been other losses for NASA and space services around the world. The Challenger and Columbia disasters demonstrated that lessons had been learned, forgotten, relearned, and forgotten again as has been the case throughout the history of human exploration. If anything, Apollo 1 stands as a reminder that whatever the Final Frontier might be, it will always be dangerous.

At the request of Grissom, White, and Chaffee's widows, Apollo 1 was made an official mission designation as the "first manned Apollo Saturn flight – failed on ground test." Grissom and Chaffee were buried at Arlington National Cemetery. Ed White was buried at West Point Cemetery. They were posthumously awarded the Congressional Space Medal of Honor.

View gallery - 20 images