The Challenger disaster grounded the space shuttle fleet for nearly three years, exposed deep flaws in NASA's leadership, and prompted significant changes to the agency's safety oversight and decision-making culture.

Watch the Challenger disaster, which killed all seven astronauts aboard, unfold live.

Watch the Challenger disaster unfold in real time

On January 28, 1986, Space Shuttle Challenger broke apart just 73 seconds after liftoff. This live CNN broadcast captures the tragedy as it happened—second by second—showing the shock and confusion of one of NASA's darkest moments.

The Challenger disaster ended NASA's plan to fly ordinary Americans in space

The explosion of the Challenger halted NASA's civilian spaceflight ambitions for decades, including plans to send teachers, journalists, artists, and other nonastronauts into orbit—an effort aimed at building public support that quietly disappeared after the 1986 disaster.

About 2.5 million American students watched the Challenger disaster live

Because of the publicity of the Teacher in Space program, millions of students viewed Challenger's liftoff in school classrooms—turning the explosion into a shared national traumatic experience marked by shock, silence, and grief.

Presidents invite guests to personalize the State of the Union

The tradition began in 1982 when Ronald Reagan honored Lenny Skutnik, who rescued a survivor from the icy Potomac after a plane crash. Since then, presidents have spotlighted a wide range of guests from Rosa Parks to Rush Limbaugh to humanize and reinforce policy themes.

The Challenger disaster delayed the launch of the Hubble Space Telescope

The 1986 explosion of the space shuttle shortly after liftoff killed seven crew members and grounded NASA's space fleet. Scientists used the downtime to refine ground control software and upgrade telescope instrument sensitivity, but maintaining the telescope's clean room storage cost NASA approximately $6M per month.

Lyndon Johnson moved the State of the Union into prime time

In January 1965, President Johnson moved the address to prime time to reach a larger TV audience, using it to promote his "Great Society" program—a push to reduce poverty, advance civil rights, and expand federal action in healthcare and economic opportunity.

The Teacher in Space program was launched in 1984 to highlight spaceflight in US classrooms

Announced by President Ronald Reagan, the program drew more than 11,000 teacher applicants nationwide. Christa McAuliffe was selected to fly on STS-51L, with plans to teach live lessons from orbit before the Challenger disaster ended the mission.

Watch the lessons Christa McAuliffe was supposed to teach aboard Challenger

After the Challenger disaster prevented McAuliffe from teaching in orbit, educators-turned-astronauts Joe Acaba and Ricky Arnold filmed her planned science demonstrations aboard the International Space Station during the 2017-18 school year.

Explore what Challenger was supposed to do on its mission

STS-51L's planned seven-day mission included deploying satellites, studying Comet Halley, conducting fluid dynamics experiments, and broadcasting live lessons from orbit—routine scientific and educational tasks that were never carried out after the shuttle was lost shortly after launch.

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 opposition party to the president first delivered a televised response in 1966

Television networks first granted airtime to the out-of-power party in 1966, with Republicans Everett Dirksen and then-Representative Gerald R. Ford delivering the inaugural response. See a list of each opposition response to the State of the Union since then.

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.

Television transformed the State of the Union, beginning with Harry Truman

In 1947, President Truman delivered the first televised State of the Union address, marking the address's shift into the visual age and expanding the president's reach beyond radio to a national TV audience.

The Columbia disaster contributed to the end of the Space Shuttle program and NASA's reliance on commercial partners such as SpaceX and Boeing to transport astronauts and cargo.

Major milestones of the Space Shuttle program's 135 missions included the launches of the Hubble Space Telescope and the Chandra X-ray Observatory, and the first American woman and African-American astronauts in space.

The Columbia disaster exposed fatal flaws in NASA's shuttle program

On Feb. 1, 2003, Space Shuttle Columbia broke apart during reentry, killing all seven astronauts aboard. The tragedy revealed long-ignored safety warnings, leading NASA to ground the shuttle fleet and overhaul its safety culture.

How a skin cancerous growth shifted an initially skeptical President Reagan on the ozone crisis

While a 1985 Nature study revealing the Antarctic ozone hole jolted public concern, Reagan's administration was more focused on the Cold War than on environmental policy. His health scare and the market potential for developing alternatives to chlorofluorocarbons helped turn the tide, leading to the Montreal Protocol's unanimous ratification by a bipartisan Senate in 1988.

A 'designated survivor' stays away from the State of the Union to ensure continuity of government

During major events like the State of the Union, one Cabinet member is kept at a secure location. This "designated survivor" would assume the presidency if a catastrophe eliminated those higher in the line of succession.

Calvin Coolidge brought the State of the Union to the radio age

On Dec. 6, 1923, President Coolidge delivered his Annual Message from the US House chamber as millions listened by radio—crowds gathered outside with amplifiers—making it the first nationally broadcast address and the only in-person State of the Union of his presidency.

Former White House speechwriters reflect on crafting the State of the Union

In this 2008 discussion, speechwriters from the Richard Nixon, Jimmy Carter, Ronald Reagan, and Bill Clinton administrations discuss how the State of the Union is written, negotiated, and used to project presidential leadership.

Amid the aftermath of Watergate, Gerald Ford declared that the state of the union was 'not good'

In his first State of the Union in January 1975, President Ford departed from the usual optimism, bluntly acknowledging recession, inflation, and public distrust as the country worked to recover from Nixon's resignation and the Watergate scandal.

See a visual history of the State of the Union

This gallery offers a visual archive of the State of the Union, featuring photographs from each president's address, beginning with Franklin D. Roosevelt. Explore decades of presidential moments, settings, and historical context tied to the annual speech.

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.

President Bush addressed the nation on 9/11 from the Oval Office

Hours after the attacks, President George W. Bush delivered a televised address from the Oval Office, vowing to bring those responsible to justice and characterizing the strikes as an attack on freedom and the American way of life.

The Challenger disaster led NASA to create an independent safety office

In response to the Challenger accident, NASA established the Office of Safety, Reliability, and Quality Assurance—now known as the Office of Safety and Mission Assurance—to strengthen oversight, elevate safety concerns, and mitigate managerial pressure on technical decisions.

Franklin D. Roosevelt was the first president to use the term 'State of the Union'

In 1934, President Roosevelt became the first president to formally call the annual address the "State of the Union," replacing the older title "Annual Message to Congress" and using the language from the Constitution.

George W. Bush delivered the first State of the Union livestreamed online

In 2002, George W. Bush became the first president to livestream the State of the Union, using the address to label Iraq, Iran, and North Korea an "axis of evil," shaping US strategy during the War on Terror.

Big Bird was almost included on the Challenger mission

As part of NASA's early outreach ideas tied to the Teacher in Space program, Sesame Street's Big Bird was briefly considered for a Challenger flight, but the plan was dropped because the oversized costume could not fit safely inside the shuttle.

In 2022, a piece of Challenger was discovered on the ocean floor

While searching for World War II wreckage near Cape Canaveral, Florida, for a documentary, divers discovered debris on the seafloor that NASA later confirmed to be a piece of Space Shuttle Challenger wreckage. The piece is at least 15-by-15 feet in size and partially buried under sand.

Engineers warned Challenger could fail, but were overruled

Engineer Bob Ebeling and four of his colleagues presented data to NASA officials and managers at NASA contractor Morton Thiokol the night before the launch about how cold temperatures could cause O-ring failure. Ebeling claims to have told his wife then that, "[Challenger is] going to blow up."

Aboard Challenger, Christa McAuliffe would have been the first teacher in space

The social studies teacher from Concord, New Hampshire, was selected from over 11,000 applicants to NASA's Teacher in Space program. Had the disaster not ended the mission, McAuliffe planned to teach lessons and conduct microgravity experiments in space.

Although it drew inspiration from spaceplane concepts of the 1920s, the Space Shuttle program began to take shape after the Space Race, as the US sought to establish a space station and a reusable transportation system for astronauts and satellites.

The evolution of the State of the Union speech

The US State of the Union speech is an annual event proposed by the country's Constitution and scheduled by its first president. President George Washington was the first to deliver such a speech, by nature of his office, limiting the inaugural "Annual Message" to 1,100 words and 10 minutes. Just 10 years later, the country's second president, John Adams, changed the nascent tradition, instead offering a written statement.

Historians reflect on the best State of the Unions ever

These political experts highlight standout State of the Union addresses that shaped the nation's direction—from Washington's first and Lincoln's Civil War messages to FDR's wartime resolve, LBJ's Great Society launch, and Clinton's scandal-shadowed 1998 speech.

Watch an American news report of the Chernobyl disaster

Americans first heard about the Chernobyl nuclear disaster two days after the event, once abnormal radiation was detected in nearby countries. This forced Soviet officials to acknowledge the catastrophe publicly for the first time a few days after it occurred.

Woodrow Wilson revived the in-person State of the Union in 1913

President Wilson became the first president since John Adams to deliver the State of the Union in person. He is credited with transforming the speech from a routine update into a public tool for advancing the president's legislative agenda.