40 years ago on January 28 the destruction of space shuttle Challenger would rock the American space agency to it’s core. Seventeen years later, shuttle Columbia was destroyed on reentry. Fourteen astronauts slipped the surly bonds of Earth to touch the face of God.
STS-51-L was the 10th flight for the orbiter named Challenger. It was a record breaking cold January morning in Florida that would cause the rubber O-rings in the solid rocket booster to stiffen and disintegrate causing a breach of hot pressurised gas from the SRB to leak through the aft attachment strut into the external propellant tank.
The resultant cascade of structual failures would lead to aerodynamic forces that would tear the spacecraft apart. A 32-month hiatus of the program would follow while an exhaustive investigation was undertaken by the Rogers Commission. It found that the potential failure of the O-rings was known about since 1977 but that both NASA and manufacturer Morton Thiokol had not addressed it.
NASA managers were also critisised for failing to heed engineers warnings about launching in such low temperatures.
The Office of Safety, Reliability and Quality Assurance was formed and expendable launch vehicles were to be preferred over crewed orbiters to launch commercial payloads.
Endeavour was built to replace Challenger, flying it’s first mission six years after Challenger’s last flight.
The shuttle program resumed, but after 11 years, in 2003, another disaster would claim the lives of seven more astronauts – orbiter Columbia disintegrating upon reentry.
The Columbia Accident Investigation Board would find that a piece of insulating foam broke free from the external tank, striking the vehicle’s termal protection system tiles on the left wing – this gouge would allow the hot atmospheric gases to penetrate the heat shield and destroy the interal structure.
The Board would also find that engineers raised concerns following the launch but were dismissed by management as previous flights had also endured similar foam shedding, limiting the investigation while the spaceflight was underway reasoning that a fix could not have been applied even if a problem was identified.
The Board was critical of the culture at NASA, comparing it to the state the space agency was in leading up to Challenger. Budget constraints compounded with a high cadence of launch operations, a lack of a safety program led to a dismissal of the safety-of-flight issues surrounding foam strikes and a lacking of appropriate communication and integration channels to manage concerns and problems to be addressed all contributing to the loss of a second orbiter.
Following another two year shuttering of the program, which also forced the suspension of International Space Station construction, numerous emergency procedures were considered – including a rescue mission, as Atlantis was being prepared for a March launch, an extension of the mission – with consideration for the lithium hydroxide canisters that remove carbon dioxide from the air supply or even an on-orbit repair – which was deemed to be a low-success probability.
We remember those lost in the pursuit of knowledge on these two missions.
Dick Scobee, Michael Smith, Ronald McNair, Ellison Inizuka, Judith Resnik, Gregory Jarvis, Christa McAuliffe, Rick Husband, William McCool, Michael Anderson, Kalpana Chawla, David Brown, Laurel Clark, Ilan Ramon.