Explore what Challenger was supposed to do on its mission

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.

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.

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.

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

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.

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 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.

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.

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.

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.

Explore the interior and exterior of the Atlantis and Endeavour space shuttles, including their flight decks, cargo bays, and other compartments.

View a timeline of NASA's Space Shuttle program, which saw five reusable orbiters take a total of 355 astronauts across a combined distance of almost six trips to the sun.

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.

View a 3D visualization of how space shuttles were built and launched into orbit from NASA's Kennedy Space Center.

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.

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.

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.

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.

Take a 360-degree tour of Discovery with Kathryn Sullivan and Charles Bolden, who flew together on the space shuttle during its deployment of the Hubble Space Telescope. (VR device-compatible)

Space tourism opportunities have been explored since the end of the Apollo era

In the 1970s, Rockwell International, a NASA contractor, and others investigated manufacturing passenger modules that could fit into the Space Shuttle's payload bay. NASA also opened spaceflights to nongovernment professionals, but many such programs were ended after the Challenger disaster, which killed the first Teacher in Space participant.

In honor of scientific exploration, all five launched space shuttles were named after ships that traveled the oceans, but a campaign from 'Star Trek' fans led to the shuttle prototype being named Enterprise.

During the Space Shuttle program, NASA's Shuttle Carrier Aircraft—two specially modified Boeing 747s—transported space shuttles between landing sites and launch facilities.

Gregory Jarvis was an Air Force veteran who flew as a civilian payload specialist on Challenger

A Hughes Aircraft engineer with a background in electrical engineering, payload specialist Gregory Jarvis was assigned to STS-51L to study how fluids and satellite propellants behave in weightlessness during shuttle maneuvers.

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.

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.

President Reagan postponed the State of the Union after Challenger

In his Oval Office address delivered the night of the disaster, President Ronald Reagan spoke directly to the nation about the loss of Challenger and its crew, postponing that evening's scheduled State of the Union to address the tragedy.

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.

Watch a firsthand account of Hubble's first service mission to repair its faulty mirror

Hubble senior project scientist David Leckrone recalls initial public ridicule over the microscopic manufacturing error that put NASA's reputation at stake. In this behind-the-scenes interview, he breaks down the innovative fix deployed by space shuttle astronauts during Hubble's first servicing mission.

Deep Impact was the first mission to probe beneath a comet's surface

The NASA mission sent a probe to deliberately crash into comet Tempel 1, producing an explosion equivalent to 4.7 tons of TNT. The payload included a compact disk with more than 625,000 names of people who participated in the "Send Your Name to a Comet!" campaign.

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.

Elon Musk's $100M investment in SpaceX was lost to three failed rocket launches

The attempts with Falcon 1 endangered the company's future but provided valuable information from which to iterate and follow up with the successful first privately funded orbital launch in history and multiple ISS resupply missions.

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.

View a gallery of all 135 space shuttle mission patches.

View a schematic of the space shuttle orbiter, including the layout of the flight deck and mid-deck for astronauts, the cargo bay for payloads, and various support systems, such as avionics equipment and the fuel system.

NASA's big dream that never came to life

Conceived in the early 1960s, the Sea Dragon was an audacious ocean-launched rocket design that would have dwarfed the Saturn V in both scale and payload—but its extreme engineering challenges kept it firmly on the drawing board.

The Polaris Dawn program led to the first commercial spacewalk

As part of the Polaris program, this first mission included a crew comprising astronauts and SpaceX engineers, who conducted scientific experiments and cultural outreach, such as raising funds for St. Jude Children's Research Hospital.

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.

In 2021 US dollars, space shuttles cost $65,400 per kilogram, making them the most expensive spacecraft for payloads greater than 20,000 kilograms.

Designs for the Hubble Space Telescope were based on Cold War spy satellites

By incorporating elements of the KH-11 KENNEN reconnaissance satellites, NASA could incorporate existing classified manufacturing expertise and infrastructure from the intelligence community to expedite the research project.

NASA's Stardust mission collected and returned samples from a comet

Launched in 1999, the spacecraft traveled to comet Wild 2 and captured more than 10,000 dust particles from its coma using a tennis racket-like mesh covered in aerogel. It also took pictures of the comet before returning to Earth and releasing the collection canister during its 2006 flyby.

Apollo 11’s design relied on shedding parts to reach, land on, and leave the moon

Despite Apollo 11 starting as a 3,000-ton spacecraft, the only part of it that returned to Earth was the small command module, which splashed down in the Pacific Ocean carrying three astronauts and moon rocks.

The Space Launch System: NASA's most powerful rocket ever

The Space Launch System is intended to be the most powerful rocket ever built by NASA. Possible missions include returning to the moon and perhaps even reaching Mars. This speculative and mostly silent video uses animation to explore the inner workings of the SLS, showing it launching and in space flight.

The European Space Agency placed a lander on the surface of a comet in 2014

Launched in 2004, the Rosetta spacecraft performed three flybys of Earth and one of Mars as gravitational slingshots to gain the necessary velocity to successfully place the Philae lander module on comet 67P/Churyumov-Gerasimenko. Philae achieved a soft landing only after bouncing twice from failed deployments of its anchoring harpoons.

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."

Watch a supercut of the various iterations of SpaceX's Starship rocket

The first version, called Starhopper, was named with the vision of developing rocket stages that could safely land after use, enabling reusability to cut costs. The endeavor was an enormous engineering challenge that required years of testing.

Most elements of the International Space Station were installed over two decades

Space shuttles delivered storage carriers, docking compartments, airlocks, solar arrays, and labs, which were assembled in low Earth orbit. The station’s Canadarm2 robotic arm, alongside maneuvering spacewalkers, has assisted with this assembly since its installation in 2001.

The unloading and maneuvering of the space shuttle's payload were accomplished by the Shuttle Remote Manipulator System—a robotic arm designed and constructed in Canada, which led to it being colloquially known as the Canadarm.

Congress settled for the Viking program after canceling the Voyager Mars program

NASA's proposed Voyager missions to Mars and Venus in the 1970s were canceled due to budget cuts and the Apollo 1 fire. The Viking program's smaller scope—focused on data collection—was the economically viable alternative to manned Mars mission proposals.

Relive the Apollo 11 moon landing minute by minute

This interactive project lets you experience Apollo 11 in real time—listening to exchanges between the astronauts and NASA's Mission Control as they guided humanity's first journey to the lunar surface and safely home.

Space telescope development was driven by a desire to bypass Earth's atmosphere

The most important figure in the effort to create what would become the Hubble Space Telescope was Lyman Spitzer, who first proposed a telescope in orbit in 1946. The nearly 50-year endeavor led to space-based observatories, which are not limited by Earth's atmosphere absorbing or distorting most wavelengths of light.