The impacting history of the Challenger tragedy

On 28 January 1986, the Space Shuttle Challenger exploded during takeoff in the middle of the TV coverage that was being carried out. Personally, I remember vividly the images I saw in later summaries and the big impression they caused me.

For reasons which are not relevant here, some time ago I had access, in one of my trips to the US, to information related to this accident. An accident that, beyond the tragedy of the deaths (all the 7 crewmembers), meant for NASA disaster and disgrace that it took time to overcome.

The information I received on this trip struck me deeply.

Although it is easy to find information on what actually happened, simply by surfing the internet, I must confess that I never before worried about looking for it, and I simply listened at the unclear news that were generated just after those tragic moments, which blamed on a mechanical failure in one of the component of the spacecraft.

But the real history is far more frightening than that.

The Space Shuttle Challenger, like its brothers Columbia, Discovery or Endeavour, was designed by NASA to have a kind of reusable system to put satellites and laboratories in orbit, and was expected to be much cheaper than the Saturn V rocket system that had been used in the Apollo program. The result was pure elegance, and a machine much more sophisticated than anything previously built.

The vehicle, with aerodynamic shape, was based on a huge rocket, which used the classic combustion of hydrogen and oxygen. In addition, the system was completed with two rockets, one at each side, full of solid fuel, which helped in boosting the takeoff.

As you can imagine, there were thousands of precision parts that composed the system, and many different manufacturers who had produced them.

In particular, the two side rockets were manufactured in Utah, by a specialized company. These rockets, despite being much smaller than the main rocket, were impressive, and were designed in pieces, which were mounted in place.

The joints between the sections of the rockets were protected by a ring of rubber. These rings prevented inflamed gases, produced during the combustion, to escape through the joints.

The drama began when, months before the launch of mission STS-51-L Challenger, one of the engineers of the company that manufactured the rockets found that these rings had failed in previous releases. Recall that the system was expected to be reusable, so that the rockets were recovered after each mission, and routinely reviewed after each recovery.

Some sections showed signs of combustion, indicating that the rings had not sealed the seam. Fortunately, the system contained a double ring, and the second ring had always resisted.

The engineer immediately reported the issue to his superiors, but was instructed to keep it confidential. The company was afraid that any setback could end its millionaire contract with NASA.

The man kept pressing on, asking for a complete review of the system and perhaps a re-design. He became unpleasant and annoying, not only for his managers, but also for some of his colleagues.

But nothing happened in months.

And so the launch date approached, announced with ceremony by President Reagan. For the first time ever, the crew included a schoolteacher, who had been selected after a long process. This teacher became a symbol, increasing the media coverage of the mission.

Already in January, the launch had been postponed several times due to various reasons. Bad weather, but also some mistakes made by NASA. That meant that the agency was under the watchful eyes of the American administration. The public also pressed, and some jokes about NASA abounded (some of these jokes were created after the broadcast of NASA technicians fixing the lock of a door with a plain saw).

For the launch week, the weather service forecast temperatures extremely low in Florida, where Cape Canaveral is.

Our man, after knowing this forecast, pressed again. He was convinced that at low temperatures the probability of failure of the rings increased, because the elasticity of the rubber drastically decreased.

On D-1, in the afternoon and evening, NASA held an emergency conference call with the manufacturer in Utah. On the table was the decision to launch or postpone.

The conference was long and hard. Another engineer supported a call off. NASA was nervous and pressed strongly the manufacturer to adopt a clear position with respect to the rings: would they function under such low temperatures or not?

The company management was afraid to say "no", so they admitted that there was not enough evidence that supported the theory of the two engineers. That was all what NASA needed to confirm the "GO" that evening.

The engineer later told that, when he got home, his wife asked him about the day. He, looking at her, replied ironically that the day had been perfect except for the fact that the next day seven astronauts would probably die.

The morning at Cape Canaveral was a freezing one. With ice deposited on the shuttle and the rockets, NASA decided to postpone the launch for several hours, waiting for the sun to heat the air a bit. Finally, under the watchful eye of politicians, scientists, engineers, families, and thousands of onlookers, NASA began the launch process at 11:38 am.

Everything seemed normal in the early moments of the launch. A careful examination, made afterwards, of the images recorded by numerous cameras showed a small dark column of smoke coming out from one of the lateral rockets. A ring was failing, and a black smoke, a product of burning fat and insulation, foretold what would come next.

At 72 seconds into the flight, the joint broke. Both the primary and the secondary rings had failed. The superheated gases escaped through the joint, and burned the side of the large main rocket. In just a few seconds, the main rocket exploded in an uncontrolled combustion of its fuel. The whole world watched horrified and speechless.

But contrary to what we may think, the Challenger did not explode, technically speaking. The uncontrolled combustion did not destroy the vehicle, but the tremendous aerodynamic forces that were generated fragmented the Shuttle in pieces. This thing makes the event even more dramatic. The front part of the Challenger, where the astronauts were, was not destroyed, and was kicked at high speed on a ballistic trajectory. A race that lasted more than two minutes, until the cabin impacted, at a huge speed against the Atlantic Ocean.

Those must have been some minutes of agony for the astronauts. Investigations later showed that some of them were alive during the first moments, as they succeed to activate some of the survival onboard systems. Those who did not lose consciousness knew that they were going to die, as the Shuttle project did not have any emergency measure for a case like this (an incident like that was simply unthinkable, and the front part was not wearing any parachute).

The brutal impact against the sea occurred at 333 kilometers per hour.

Days after the tragedy that shocked the world, President Reagan created a commission of experts to clarify the causes of the accident. A Nobel Prize in physics (Richard Feynman) was in that committee, as well as the famous astronaut Neil Armstrong, among others.

The thesis of the NASA and the rings manufacturer officials was that there had been no clear evidences that would justify a postponement of the launch. It is interesting to note that, many years later, some of those managers, now retired, still maintain the same position, and defend that the decision to go ahead was correct.

On the other hand, the two engineers explained that the probability of a default of the rings at low temperatures was very high, and that the operation should have been aborted.

I can imagine the difficulty of the investigation, given the large amount of technical detail and complex terminology that was probably used.

One of the key moments of the investigation, like in the Hollywood best suspense films, arrived when Feynman asked for a sample of the ring rubber, a clamp, and a glass of ice water. In the eyes of his fellow committee members, he submerged the piece of rubber, pressed and deformed with the clamp, in the icy water. After pulling it from the water, and freeing it from the pressure of the clip, the frozen gum, designed to be flexible, was unable to recover its original shape. It had lost all its elasticity in cold water. It was a simple, but shocking, piece of evidence.

Finally, the commission determined that the accident was caused by the malfunction of the ring, but did not directly blame anyone.

The engineer that had pressed to cancel the launch left his job, because the bad relationship that had developed with his superiors and many of his colleagues. He dedicated to give lectures until his death from cancer in 2012.

The manufacturer had to stand a considerable economic penalty.

NASA had to endure the shame of seeing that their quality systems and their protocols for possible crisis had failed miserably. That wound took a long time to heal, and in fact it jeopardized the whole spatial program for many years afterwards. Of course, the complete Shuttle program was reviewed. In the case of the lateral rockets, the system of rings was redesigned.

Looking at it from the perspective of time, it seems absolutely incredible that NASA decided to go ahead with that launch. Yes, it is true: risk is inherent to the spatial career. Everything is brought to the limit of the technology. And the risk of a tragedy must be accepted.

But this is about a bad decision, taken for convenience. Out of the 4 specialized engineers who had attended the evening conference the day before launch, 2 of them said NO. The third one had not been clear in his position. Only one of them had been for the launch. And despite this, the managers of the company, with their minds focused on the contract with NASA and the penalties for delaying the launch, had ignored the opinion of their own specialists.

Also NASA, under the pressure of a possible launch delay, had preferred to "look elsewhere" and somehow pressured to hear from its provider just what it wanted to hear.

Of course, nobody wanted that tragic result. In fact, the likelihood of such an accident was about one percent (anyway, an unacceptably high probability when it comes to human lives).

To err is human, but for many this is an example of a decision based on parameters which were ethically wrong.

(This article has been written by a non native English speaking author. Please forgive any grammatical and stylistic mistake)