Engineers warned Challenger could fail, but were overruled

The night before the disaster, not everyone signed the Challenger's launch authorization form

Allan McDonald, director of the booster rocket program at NASA contractor Morton Thiokol, refused to sign, believing ice on the spacecraft could damage the orbiter's heat tiles and that cold temperatures could cause O-ring failure. He later testified that management had overruled objections from engineers.

The Challenger disaster exposed flawed priorities in NASA's leadership

Reported issues with the shuttle's O-rings were deemed "acceptable risks" to proceed with the launch and ensure President Reagan could mention the success of Challenger in his State of the Union address. Postponing the launch would have also limited the publicity of educator Christa McAuliffe's live lesson from space.

Low temperatures led to the equipment failure that caused the Challenger disaster

The polymer chains that make up an O-ring give it the ability to quickly deform and fill in gaps to seal fluids, including the hot gases from the Challenger's rocket boosters. Cold weather on the day of launch stiffened the O-rings, reducing their flexibility and sealing properties.

Listen to the five-part podcast series that reconstructs how Challenger failed

The "American Scandal" podcast devotes a five-part series to Challenger, tracing the engineering warnings, internal pressure to launch, the moment of the explosion, and the long aftermath that reshaped NASA's safety culture.

Richard Feynman exposed NASA's safety failures on the Rogers Commission

The Nobel Laureate served on the Rogers Commission investigating Challenger, famously demonstrating O-ring failure with ice water and eventually criticizing NASA's culture of risk normalization and management pressure in the final report.

Faulty wiring and flammable materials caused a fire in the Apollo 1 command module

During a launch rehearsal test on Jan. 27, 1967, the fire took the lives of astronauts Gus Grissom, Ed White, and Roger Chaffee. The tragedy led to improvements to CM construction and the development of a single-piece hatch for escapes.

Evidence suggests some of the Challenger's crew may have been alive after the explosion

Recovery of the intact crew cabin and later analysis of flight data led investigators to conclude the astronauts likely survived the initial breakup and remained alive during the roughly two-minute descent before the cabin struck the ocean.

The commander of the Challenger mission began his career as a mechanic in the Air Force

Lt. Col. Dick Scobee began his career as an Air Force aircraft mechanic, later becoming a Vietnam combat pilot, test pilot at Edwards Air Force Base, and ultimately the commander of Challenger's STS-51L mission.

An oxygen tank explosion forced Apollo 13 to abort its moon landing

The 1970 mission—intended to be the third lunar landing—forced astronauts Jim Lovell, Jack Swigert, and Fred Haise to focus solely on their survival. They engineered a makeshift filter to handle the carbon dioxide they produced, which exceeded the lunar module's capacity.

A Manhattan building doomed to collapse was saved in secret

After completing the Citicorp Center, its engineer realized that cost-cutting measures to use bolted instead of welded joints made the building vulnerable to collapse under quartering winds. For three months, crews worked in secret at night to reinforce the building under Project Serene.

Einstein warned the president that splitting atoms could lead to powerful bombs

In a 1939 letter to Franklin D. Roosevelt, Albert Einstein explained that nuclear fission could produce immense energy—and devastating weapons. The warning helped spur the Manhattan Project, a role Einstein later deeply regretted.

Viking mission planning director Gentry Lee (1942–) on getting to Mars

"We didn't know then what we know now, which is how tough it really is to land on Mars."

An imbalance in nuclear reactivity factors caused Chernobyl's reactor to explode

The initial explosion resulted from excessive steam pressure that had built up in a runaway manner due to design flaws and violations of safety protocols. Once exposed to atmospheric oxygen, the hot graphite in the control rods underwent a combustion reaction, resulting in a secondary explosion.

Orville and Wilbur argued over everything, likely accelerating their progress

The two never married, and focused solely on their goal of achieving flight. While both were socially reserved, they were passionate about their project, regularly debating—even shouting—over the details of propellers, engines, wings and more. This video explores how their culture of open argument likely fueled their discoveries.

The engineers proposing massive airbags for airplanes

Though they are famously rare, airplane crashes are some of the most shocking catastrophes when they occur. These researchers are dreaming up an implausible safety feature to help crashing planes land safely.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

See the unbuilt rocket design that would have dwarfed the Saturn V

Designed in the early 1960s, the Sea Dragon was a radical concept for an ocean-launched rocket that would have far exceeded the Saturn V in size and payload. The conceptual design was ultimately too risky and impractical to build.

The story of two female programmers running the simulations behind chaos theory's discovery

Margaret Hamilton and Ellen Fetter worked on MIT's 800-pound Royal McBee LGP-30 computer, which was fed binary code on paper tape to perform computations. Among the computations performed were those involving equations describing the motion of gas in a circulating fluid for Edward Lorenz, widely considered the father of chaos theory.

Webb's sunshield enables extreme cooling for precision space observation

To avoid interference from its own heat, the telescope uses a five-layer shield to stay ultra-cold and stable, allowing its instruments to function at cryogenic temperatures. One instrument, MIRI, gets so cold it needs a helium-powered cooler to reach just 7 Kelvin, or -447°F.

Many believe a cataclysmic volcanic eruption is imminent at Yellowstone, though experts say it is unlikely

Mike Poland, a scientist at the Yellowstone Volcano Observatory, estimates the likelihood of the event at one in a million. He cautions, though, that the park poses other potential dangers, including steam explosions and earthquakes.

Project STORMFURY explored modifying hurricanes with silver iodide

Between 1962 and 1983, researchers at the National Oceanic and Atmospheric Administration investigated whether weakening and controlling hurricanes was possible. The investigation showed very few hurricanes met the criteria for modification, despite successfully weakening two storms.

Why helium helped preserve the US' founding documents, but was later replaced

In 1951, the Charters of Freedom were stored in glass and metal cases filled with helium, which would not chemically react with the documents. After microscopic cracks were identified in the glass through which helium could leak out of and—experts feared—pollutants could infiltrate, new encasements made of aluminum, titanium, and argon replaced the old system in 2003.

Large oil companies knew about the impact of carbon emissions since the ’70s

PBS Frontline’s The Power of Big Oil reveals how industry giants like Exxon and Shell were researching climate change in the 1970s but then funded denial campaigns—using internal science to sow public doubt for decades.

Read the only firsthand account of the Pompeii disaster

In two letters to historian Tacitus, Roman official Pliny the Younger describes the eruption from afar—earth-shaking, sky-darkening, and seawater retreating—and recounts how his uncle, Pliny the Elder, died while attempting a rescue.

'Many of life's failures are people who did not realize how close they were to success when they gave up.'

- Inventor Thomas Edison (1847 - 1931)

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

In 1915, workers recovered a submarine-like vessel from the Chicago River, prompting fears of German espionage

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

Exploring the Larry Bird punch that almost changed March Madness

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

The Beatles' US label rejected the band's first two singles, 'Please Please Me' and 'From Me to You,' with one executive calling the band 'dead in the water.'

Elk Cloner, the first computer virus to spread in public, was written as a practical joke by Richard Skrenta, a Pittsburgh high school student.

See images of medical cases of firework injuries shared on this 'Instagram for doctors.' (Warning: Graphic content)

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

Before the current East Wing ballroom project, only two White House renovations in the past 100 years cost more than $10M.

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

Comedy legend Catherine O'Hara, star of 'Schitt's Creek' and 'Home Alone,' quit 'Saturday Night Live' after just one week to return to her old job.