On the morning of February 1, 2003, US President George W. Bush went live on television to address to the American public. It was the second time during his still young presidency that Bush had had to break bad news to the nation. What Bush had to say said would shake America and, indeed, the entire world.

"My fellow Americans, this day has brought terrible news and great sadness to our country," he said, "the Columbia is lost. There are no survivors."

A few hours earlier, just before 8:50 a.m. eastern time in the US, a sensor on the shuttle had reported a strain on the spacecraft's left wing. The wing was higher than it should have been. But that warning was not displayed to the crew.

And within minutes, Columbia's return to Earth turned to disaster, leaving the crew of seven to perish.

A vehicle of exploration

Columbia was the American space agency NASA's first active space shuttle.

The shuttle or orbiter, as it was also known, was a white, plane-shaped spacecraft that became symbolic of NASA's space program, and more generally, space exploration in the late 1970s and 80s. 

From 1981 to 2003, Columbia flew 28 times, including that fateful, final mission.

Columbia STS-107 was a routine mission to conduct scientific experiments in space. It launched from Kennedy Space Center in Florida, USA, on January 16, 2003. 

But right from the start, things had gone wrong. A piece of foam — used to insulate the shuttle's super-cold fuel — had broken off from a booster rocket during the launch from Earth. And that bit of foam had hit the wing of the orbiter.

Failure of damage assessment

By the second day of the mission, NASA had discovered what had happened. But a decision was made to continue with the mission without fixing the damage or evacuating the astronauts.

The crew was notified about the debris strike via an email from mission control, but was assured that the "same phenomenon [had been seen] on several other flights" and that there was "absolutely no concern" about its affecting their re-entry into Earth's atmosphere.

But when the Columbia shuttle began its descent back to Earth after roughly two weeks in space, the decision to do nothing proved to be wrong — and fatal.

Fate of the astronauts

After the accident, a team of investigators known as the Columbia Accident Investigation Board (CAIB) looked into what had happened.

The CAIB concluded that when the foam broke off during launch, it "breached" or damaged an outer thermal protection system. That damage had then allowed "superheated air" to melt the orbiter's aluminum structure.

Ultimately, that had caused the orbiter to breakup during its re-entry and descent to Earth. The investigators found debris scattered on the ground.

The astronauts onboard the Columbia shuttle probably experienced a rapid depressurization due to the breakup about a minute and thirty seconds after the final words of the crew were transmitted to mission control. Then, they lost the connection.

It is unclear whether that depressurization was their cause of death. They were likely also exposed to severe physical trauma when the spaceship started spinning rapidly.

Then as the spaceship disintegrated, their now unprotected bodies would have been exposed to extreme heat due to atmospheric friction.

And, finally, there was the impact on the ground. But it could also be seen, as it happened above people's heads in the sky.

Spaceflight is still difficult and dangerous

The story and investigation into the 2003 Columbia space shuttle accident illustrates how dangerous and difficult spaceflight was — and is to this day.

At the time, the CAIB described spaceflight as being in a "developmental" phase — and that was 30 years after the Apollo moon missions. Those missions were a huge success for space exploration overall, but they were also marked by technical difficulties and tragedy.

A 2022 research papernoted that the highest fatality rate in spaceflight was in the 1960s. The lowest was in the 1990s and that "since 2003, no astronaut fatality has been reported."

The study authors calculated a total fatality rate (deaths per spaceflight) of 5.8% up to the paper's publication in 2022.

"With greater international cooperation and maintaining of the International Space Station (ISS), the number of manned spaceflights and days spent in space has constantly increased," wrote the researchers, adding that there had been "constantly lower rates of incidents and accidents."

Spaceflight is no less difficult today than it was 20 years ago, or in the 1960s, but space agencies have introduced safety reforms and regulations as our knowledge and experience of space improves.

Was NASA to blame for the Columbia shuttle accident?

As the Investigation Board concluded, there were — what they called — "organizational causes" for the disaster.

That suggests that NASA, as an organization, bore some responsibility for what happened. But no individuals at NASA or elsewhere were ever charged with any form of culpability.

An option left untaken

It is likely that the lives of the Columbia's crew could have been saved.

While the Investigation Board judged that it was unlikely that the damage to the orbiter could have been repaired in space, the CAIB said it would have been "challenging but feasible" to launch the Atlantis, another space shuttle, to save the astronauts on the Columbia shuttle.

They said that by working around-the-clock shifts, seven days a week, the Atlantis could have been prepared for launch by February 10 — five days before food and other resources on the Columbia would have run out.

But the plan was not put into action.

Edited by: Zulfikar Abbany