A cloud of vapour engulfs the space shuttle Challenger in a picture taken on the morning of January 28, 1986. The disaster claimed the lives of all seven astronauts on board, including high school teacher Christa McAuliffe, and brought NASA's human spaceflight program to an abrupt but temporary halt.
Now, 30 years on from the tragedy, the story of what exactly happened to Challenger remains clouded by faulty memories and misinformation.
Take a look back at the compelling story of Space Shuttle Challenger’s ill-fated 1986 flight with recently discovered lost tapes and rare footage in Challenger Disaster: Lost Tapes - Thursday 28 January at 7.30pm AEDT/NZDT
Myth 1: Challenger Exploded
For example, one commonly repeated myth is that Challenger exploded 73 seconds after launching from Kennedy Space Center in Florida.
"The shuttle itself did not explode," said Valerie Neal, space shuttle curator at the National Air and Space Museum in Washington, D.C. "I think the origin of that myth is that it looked like an explosion, and the media called it an explosion."
Even NASA officials mistakenly called the event an explosion as the tragedy unfurled. For example, NASA public affairs officer Steve Nesbitt said at the time that "we have a report from the flight dynamics officer that the vehicle has exploded."
Investigations would later reveal, however, that what actually happened was much more complicated, curator Neal said.
The space shuttle's external fuel tank had collapsed, releasing all its liquid hydrogen and liquid oxygen propellants. As the chemicals mixed, they ignited to create a giant fireball thousands of feet in the air. The shuttle itself, however, was still intact at this point and still rising, but it was quickly becoming unstable.
"The shuttle orbiter was trying very hard to stay on its path, because it sensed something very irregular was happening underneath it," Neal said.
"Finally it broke off the tank and—moving so fast but without its boosters and tank—it couldn't tolerate the aerodynamic forces.
"The tail and the main engine section broke off. Both of the wings broke off. The crew cabin and the forward fuselage separated from the payload pay, and those big chunks fell out of the sky, and they further broke up when they hit the water."
Myth 2: Challenger Crew Died Instantly
The seven-astronaut crew for the space shuttle Challenger's fatal mission smile for the cameras as they leave for the launch pad 25 years ago, on January 27, 1986.
Another myth—popular perhaps because it is, in a way, comforting—is that Challenger's seven astronauts died instantly when the shuttle "exploded."
But the shuttle crew was not blown up, nor did they die when the shuttle broke apart. Although the exact cause of death is unknown, many experts now think the astronauts were alive until the crew cabin hit the Atlantic Ocean at more than 321 kilometres an hour.
"They were still strapped in their seats when they were found," the National Air and Space Museum's Neal said.
What's less clear is whether the astronauts were conscious during their final moments. A NASA medical report concluded that "it is possible, but not certain, that the crew lost consciousness due to an in-flight loss of crew module pressure."
Myth 3: Millions Watched on Live TV
In the hours and days following the disaster, footage of the Challenger accident was "replayed incessantly" on the major television networks, Neal said. This could explain why many people "remember" witnessing Challenger's destruction live on television, when in fact what they probably saw was a replay.
"It's false that most people saw the disaster live on TV," Neal said.
For one thing, most of the major TV networks did not broadcast the launch live. For another, the launch occurred on a Tuesday at 11:39 a.m., Eastern Time, when most people across the country were at work.
The handful of people who did see the tragedy unfold on live television were watching it on NASA's channel via satellite dishes—technology that relatively few people had at the time—or on CNN.
Myth 4: Cold Caused the Disaster
Icicles hang from the space shuttle launch tower at Kennedy Space Center in Florida in a picture taken during an inspection on the morning of the Challenger disaster.
Temperatures on the day of Challenger's launch were below freezing Celsius—the coldest ever recorded for a shuttle launch, shuttle historian Neal said.
A common myth is that cold temperatures were the reason for the failure of a rubber o ring, which helped seal a crucial joint in the shuttle's right solid rocket booster (SRB). But blaming the o ring failure on the cold is an oversimplification, Neal said.
"Temperature alone wasn't the problem," she said. The engineers "had seen evidence of partial o ring failures before on launch days that were not as cold."
Investigations later determined that the root cause of the accident was a leak in the SRB joint, which had allowed superheated gas to escape and burn through the booster and the external tank, causing structural collapse.
"The post-flight analysis indicated that the cold temperature was certainly a contributing factor. But so was the [SRB] joint's design and [NASA's] decision-making process. It was like a perfect storm of combined circumstances."
Myth 5: Shuttles Now Have Ejection Seats
Startled birds seem to surround the space shuttle Challenger as it rises on a column of exhaust vapour from Kennedy Space Center in Florida—moments before the shuttle's destruction 25 years ago.
Another Challenger myth Neal has heard repeatedly is that NASA ordered ejection seats built into the other shuttles following the disaster. But ejection seats wouldn't have saved all of the Challenger astronauts, and their presence may even have been dangerous to the crew.
Ejection seats "are heavy and cumbersome, and they are themselves a safety hazard, because they have pyrotechnics in them," Neal said. And even if ejection seats had been installed in Challenger, she added, "they would have only been there for the commander and the co-pilot, the ones actually flying the shuttle."
Following the Challenger accident, NASA did require that the other remaining shuttles be outfitted with a bail-out system, which consists of a ten-foot-long (three-meter-long) "escape pole" that can be deployed during emergencies.
Astronauts can "hook on to the pole, slide out to the end, drop off under the shuttle wing, and then parachute to safety," Neal explained. A major limitation of the bail-out system, however, is that it is designed to work only in very specific emergency situations.
"The orbiter has to be horizontal, and it has to be in stable flight at a certain speed and altitude," Neal said. The bail-out system "would not have been of any value in the Challenger situation, because the shuttle was pointed straight up and accelerating" when the accident happened.
By Ker Than