'Oh my God, no!' Space shuttle Challenger exploded 39 years ago

Corrections & Clarifications: An earlier version of this story misstated the date of the Space Shuttle Columbia disaster. It occurred Feb. 1, 2003.

For millions of Americans, it was an event that would be seared into their memories for the rest of their lives – on par with the Kennedy assassination and 9/11.

On that chilly January day in 1986, students and teachers across the nation waited in awe and wonder, primed to watch and learn from the first teacher in space as she soared to new heights from a launch pad in Florida. Students gathered around model space shuttles. Teachers switched on TVs to show the often-delayed countdown.

Then, in a blistering white flash, a science lesson tragically exploded into a human lesson. Seven lives disappeared in the brilliant blue sky over Florida.

It was the first time American astronauts were killed in flight, spanning 56 manned missions that began in 1961.

On Tuesday, the nation marks the 39th anniversary of the explosion that destroyed Challenger 73 seconds after liftoff after a failure in the shuttle’s right solid rocket booster.

Historical significance of the disaster

Americans were well aware of the historical significance of the tragedy. The day after the explosion, a Paste BN story said: "The Challenger disaster seems fated for a place beside the Kennedy assassination in the nation's memory. People will always remember where they were and what they were doing, and the catastrophe will shape the thoughts, and lives of the millions watching."

Marie Ishee, a science teacher at Houston's Northbrook Senior High School, told Paste BN she "had the same feeling when John F. Kennedy was shot. I couldn't believe it."

Tom Kriner, of Chambersburg, Pennsylvania, echoed similar pangs of sorrow. "I felt like the day Kennedy was shot. It's just that empty feeling deep down. I guess this is just one of those things that will heal in time."

Salem, Connecticut, mathematics teacher David H. Wordell, who had been a finalist for the teacher slot on Challenger, worried about his students. "It will scar them. It will take a long time to get over such a personal tragedy."

What happened in the Challenger launch?

In Florida, thousands still step outside and look up when rockets thrust into the sky from Cape Canaveral. On the unusually frosty morning of Jan. 28, 1986, Floridians saw the familiar plume from the launch fork off in two directions and knew immediately that something was wrong.

Moments later, NASA commentator Steve Nesbitt uttered unsettling words: "Flight controllers here are looking very carefully at the situation. Obviously a major malfunction."

The seven crew members lost in the explosion were Michael J. Smith, Francis “Dick” Scobee, Ronald McNair, Ellison Onizuka, Gregory Jarvis, Judith Resnik and teacher Christa McAuliffe.

The flight was the shuttle program’s 25th mission and the first time a civilian, McAuliffe, had flown on a shuttle. Classrooms across America watched the launch.

The shuttle was supposed to make spaceflight routine. After nine missions in 1985, the most in any calendar year, policies called for increasing to as many as 24 flights annually.

'Something went wrong'

The words of first lady Nancy Reagan − "Oh my God, no!" − captured the horror of the tragedy that stunned the nation.

But for the residents of Brevard County, Florida, home to Kennedy Space Center, the Challenger explosion was personal.

Bill Kerr, a biologist who did consulting work for endangered species and wetlands, watched Challenger’s launch from a big window in his office.

“When you live where I live, you can see all the rockets go up,” Kerr said. So when the vapor trail split, “you knew something went wrong. It was obvious.”

Mary Jean Thompson, who founded Dixie Crossroads Seafood Restaurant, a Titusville landmark, with her husband just three years before, said the launch was something "you'll never forget."

"It's imprinted in your mind forever," Thompson said. The family usually watched the launch on TV, running outside when the final countdown started to watch the sky. It was so cold that morning that Thompson said she stayed inside, watching it all on television.

As soon as the shuttle’s vapor trails split in several directions, she said, “you knew something was wrong.”

Thompson’s daughter, Laurilee, was on a fishing boat off Florida’s Southwest Gulf Coast and didn’t hear about the shuttle until a week later, when her thoughts immediately turned to what it meant at home.

“Every time the shuttle launched, there was this huge influx of people coming to town,” she said. When the shuttles were grounded, “it was a huge hit to the economy in Titusville and north Brevard.”

What went wrong and why?

Immediately after the explosion, NASA began working to determine what went wrong and why. It would be 32 months before another shuttle left a launch pad.

Within days, NASA concluded two rubber O-rings in Challenger’s right solid rocket booster had failed because temperatures overnight dropped into the low 20s. Hot gases burned through and caused an explosion of the external fuel tank.

The Rogers Commission, an external review panel appointed by President Ronald Reagan, soon discovered several of the manufacturing engineers had recommended against launching the shuttle in the extraordinarily cold air that morning but had been overruled by managers who were talking with a group of NASA officials, wrote John M. Logsdon for a NASA history project. The panel broadened its review to NASA management.

Ultimately, the panel criticized NASA’s process for addressing flight risks and concluded pressure to keep the shuttle flights on schedule compromised safety, reported Florida Today, a Paste BN network newspaper.

“The decision to launch the Challenger was flawed,” the commission concluded. “If the decision makers had known all of the facts, it is highly unlikely that they would have decided to launch."

After working to improve the booster design and creating new management practices to improve safety, NASA relaunched shuttle flights on Sept. 29, 1988, when Discovery lifted off from the space center.

A second space shuttle disaster

Seventeen years after the Challenger disaster, another shuttle and its crew were lost in the skies above America: The shuttle Columbia broke apart upon reentry on Feb. 1, 2003, killing all seven astronauts aboard. According to NASA, the shuttle was lost about 15 minutes before it was set to touch down at Kennedy Space Center.

The shuttle disintegrated as it reentered the atmosphere, and pieces of the craft streaked across the sky. Parts of the shattered shuttle rained down across a broad expanses, much of it over Hemphill, Texas.

The disaster was attributed to a a piece of foam that fell from the external rocket tank during launch, which opened a hole in a shuttle wing that caused the craft to rip apart on reentry.

The accident investigation spread blame broadly, citing management and organizational deficiencies. Among them: a culture that didn't like to hear safety concerns from lower-level engineers.

Space shuttle program ends

After the Columbia disaster, shuttle flights were again grounded. On Jan. 14, 2004, President George W. Bush announced a “new vision” for the nation’s space exploration program.

Bush declared that the shuttle would return to flight “as soon as possible,” consistent with the recommendations of the Columbia Accident Investigation Board, and that the chief purpose would be completing assembly of the International Space Station. He also announced the shuttles would be retired from service.

The space shuttle flight program came to a close on July 21, 2011, when Atlantis landed at Kennedy Space Center in Florida.

It had been more than 40 years since President Richard Nixon had announced in January 1970 that the nation should build a new type of space transportation vehicle that could “shuttle repeatedly from Earth to orbit and back."

From the initial flight of the “world’s first reusable spacecraft,” on April 12, 1981, to the final flight, the 184-foot-long shuttles flew 135 missions.

Day of Remembrance held each January

To honor the astronauts lost in the Challenger accident, as well as the three who died in the Apollo 1 launch pad fire in 1967 and the Columbia accident, every year at the end of January NASA holds a Day of Remembrance.

This year, the Day of Remembrance was observed Jan. 23.

"The day allows NASA employees to reflect not only on the lives lost but also on the circumstances that led to the accidents and the resulting changes to NASA’s operations and safety culture," NASA said in a statement. "It is also a time to ensure that everyone does their utmost to prevent future tragedies from happening through a heightened culture of safety and excellence."

Contributing: L.A. Jolidon, William Welch and Traci Watson, Paste BN; James Dean and Brooke Edwards, FLORIDA TODAY