This Thursday marks 30 years since the U.S. Space Shuttle Challenger and its seven-member crew were lost in a cataclysmic explosion, moments after liftoff, in the skies above Florida.

The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST. Destruction of the launch vehicle began after an O-ring seal in its right solid rocket booster failed at liftoff. The entire crew – seven men and women – were lost.

The disaster resulted in a 32-month hiatus in the shuttle program and the formation of the Rogers Commission appointed by President Ronald Reagan to investigate the accident. The Rogers Commission found NASA’s organizational culture and decision-making processes had been key contributing factors to the accident.

Media coverage of the accident was extensive: one study reported that 85 percent of Americans surveyed had heard the news within an hour of the accident. Many viewed the launch live because of the presence on the crew of Christa McAuliffe, the first member of the Teacher in Space Project.

The Challenger disaster has been used as a case study in many discussions of engineering safety and workplace ethics.

The story of Challenger’s last moments is recounted in the following two-minute clip from NASA TV’s 2011 production, The Space Shuttle.

That night, President Ronald Reagan spoke to the nation from his desk in the Oval Office. “We mourn their loss as a nation together,” he said of the Challenger astronauts.

He acknowledged the grief of the families. For children, he emphasized that pain and loss can be part of exploration.

“The future doesn’t belong to the fainthearted; it belongs to the brave,” he said.

He reiterated his support for the space program, insisting that nothing that had happened to the Challenger diminished its achievements. (This was before the discovery that a foreseen event, frozen “O” rings, caused the explosion.)

“There will be more shuttle flights and more shuttle crews, and, yes . . . more teachers in space,” said the President.

He finished by quoting from a poem much beloved by aviators, “High Flight,” written by John McGee Jr., an American who flew for the Royal Canadian Air Force in World War II and was killed in a mid-air collision.

The Challenger astronauts had “waved goodbye and ‘slipped the surly bonds of earth’ to ‘touch the face of God,’ ” concluded Reagan.

The speech took four minutes. Today it is widely considered an outstanding example of a US President serving as the definer of national events, in effect the interpreter-in-chief — viewed by many as one of the president’s most important duties.