At Cape Canaveral, a test of a command module meant to be the exit route for astronauts was marred by tragedy when it caught fire during operation. Three people perished.
The fire was started by chafed wires and flammable materials ignited by pure oxygen and further exasperated by pressurization in the cabin. It served as a stark reminder of NASA’s penchant for speed over safety.
Electrical Arcs
Apollo 1 crewmembers had to wear thick, insulated suits in order to prevent overheating; unfortunately, their insulation became worn and torn, leaving exposed wires exposed. When these wires came into contact with one another they arced, sparking fire which killed all six astronauts aboard Apollo 1.
Electrical arcs or sparks are one of the leading causes of cockpit fires. An electrical arc may cause metal to melt and quickly spread throughout an aircraft, causing major damage and forcing an evacuation. To combat this problem, engineers design aircraft with multiple push-button circuit breakers which automatically stop functioning if an issue arises – this way arcs cannot ignite in flight and spread further damage.
Apollo 1 fire was started by sparks igniting pure oxygen gas which is highly combustible, combined with pressurization in its cabin making escape more difficult for astronauts than intended. After five minutes, they became overcome by toxic smoke and carbon monoxide levels and died asphyxiation from carbon monoxide poisoning.
Short in a bundle of wiring somewhere beneath the command module’s commander seat set off an inferno that quickly spread, devouring everything it touched: nylon netting, helmet covers, spacesuit straps, aluminum coolant tubes and oxygen hoses surrounding the astronauts; it even caused its outer shell to melt, rapidly pressurizing its interior without them being able to exit through its small, inward-opening hatchway.
Grissom, White and Chaffee were trapped inside their capsule until it was destroyed by fire. Due to thick smoke and high temperatures inside, their hatch was impossible to open in time and became impossible for the astronauts.
NASA was left reeling after this accident, with their manned lunar program coming to a standstill and their lunar program collapsing as well as being considered a setback to Soviet efforts at their own manned moon mission. Recovery would take years; as operations resumed after rebuilding was underway new goals were established that prioritized safety while still meeting cost reduction goals and maintaining fast schedules.
Extensive Combustible Materials
As part of any thorough root cause analysis, one should carefully consider where and when an event took place (onboard Apollo 1 / Saturn space vehicle), its place (Cape Canaveral), and task being completed at that time (launch pad test). Here, excessive use of combustible materials contributed significantly to the fire; astronauts’ capsule was highly pressurized with pure oxygen which creates an explosive environment where items that normally wouldn’t burst into flames suddenly would do just that, such as Velcro strips used to secure loose gear inside, although unfortunately these strips weren’t removed as required by safety rules resulting in increased fire spread.
The review board determined that the astronauts’ deaths were the result of several lethal conditions in the command module, including uncontrolled ignition, an unprotected electrical wiring system, overpressurization with too much pure oxygen and too little air, numerous flammable materials in the cockpit that ignited on contact, an ineffective hatch design that prevented quick opening, as well as pre-launch procedures including tests of crew ability to close it quickly enough.
During their final test, Grissom and White struggled to open the hatch in time to escape before their cabin filled with smoke and toxic fumes; their attempts at escape proved futile as lack of oxygen caused their deaths in mere seconds.
The Apollo 1 fire revolutionized NASA’s manned space program. Following this tragedy, extensive evaluation and redesign efforts were conducted on its command module and many safety problems were fixed in 1969 when astronauts achieved their objective of landing men on the moon. Today, its remains remain stored at NASA Langley Research Center as a reminder of this horrific episode which nearly derailed our country’s attempt at landing on the Moon; but more importantly as an important reminder of conducting thorough and objective root cause analyses to avoid similar tragedies in future attempts at sending men there.
Poor Insulation
Five decades ago, during a plugs-out ground systems test at Cape Kennedy in Florida, fire engulfed the Apollo 1 spacecraft, killing astronauts Virgil “Gus” Grissom, Ed White and Roger Chaffee and nearly derailing President John F. Kennedy’s dream to land humans on the Moon before the decade was out. Furthermore, NASA was badly damaged as subsequent investigations strongly criticised both its design and inadequate safety procedures in place at that time.
Poor insulation was one of the primary factors leading to this fire. North American Aviation constructed the command module as a three-man craft designed to take astronauts from Earth to Moon and back again; its cabin was pressurized with pure oxygen which is highly flammable; fire quickly spread throughout nylon nets used for collecting dropped items and Velcro strips attached to its walls, trapping astronauts in their chairs before they could escape through its innermost, inward-opening hatch.
Investigators determined that while its source was uncertain, most likely an electrical arc occurred within wires located beneath Grissom’s seat and provided power for his cockpit controls. When exposed to heat from an ignition source, their protective Teflon coating easily became damaged; when electrical sparks occurred during combustion of surrounding materials that ignited easily and spread the fire quickly.
The fire was so intense that its heat burned holes through astronauts’ helmets and suits; their faces were scorched from exposure; holes were even burned into the command module’s hull itself by its heat; some even managed to escape through its air vents.
As the fire raged, Shea ordered his crew to traverse through the spacecraft and remove all combustible material from their seats. Although Shea’s decision was met with criticism by congressional committees at first, later interviews would reveal him to defend it on grounds that had issues been dealt with earlier, astronauts may have remained safe.
Poor Design
Fifty years ago, one of the greatest tragedies in US space exploration occurred at Cape Kennedy during a systems test for Apollo-1’s first crewed mission. A catastrophic fire broke out inside the Command Module, killing astronauts Virgil “Gus” Grissom, Ed White and Roger Chaffee and prompting increased awareness about the risks inherent to space travel. This tragedy not only set back President John F. Kennedy’s promise to put men on the moon; it also raised public consciousness regarding these inherent dangers associated with rocketry launch operations.
Due to temperatures high enough to melt aluminum, investigators were never able to accurately pinpoint the cause of the fire; however, several causes have been identified including improperly secured and insulated electrical wiring, exposed combustible materials, and poor design preventing crewmembers from quickly exiting their Command Module.
As a result of this incident, it took five minutes for the hatch of the spacecraft to open, making egress difficult for astronauts as smoke and heat entered their cabins. Grissom died due to lack of oxygen rather than from fire directly; but in his final moments was unable to open his hatch due to outer layers being compromised by flames burning through and stopping him from opening it.
Grissom had numerous grievances against NASA and the contractors designing and building Apollo spacecraft, particularly North American Aviation. He found them unwilling to share data and information with him which he found frustrating; furthermore he found it disappointing that their Command Module was designed for flight under pure oxygen rather than the less dangerous nitrogen-oxygen mixture used during ground testing.
Even with these complaints, he remained committed to the mission. At no point would an accident stop his progress; at the last moment, he begged spacecraft manager Joe Shea (Joe Shea in case you forgot!) to allow him to sit in the cabin during systems tests with two colleagues; Shea considered this proposal but ultimately declined, considering how cramped the spacecraft cabin might become in order to accommodate everyone inside while wearing headsets shirtsleeves!