Maxime Faget, Director of Engineering and Development at the Johnson Space Center in 1969, holding his balsa model of a prototype shuttle orbiter. NASA

Faget’s original shuttle design envisioned the astronauts aboard the orbiter carried to the edge of space by a crewed booster vehicle, which would return to Earth and land on a runway like an airliner. In this artist’s impression from 1970, the orbiter is peeling away in the background. NASA

Dorothy “Dottie” Lee, photographed in 1976. As a Senior Aerothermodynamics Engineer, Lee helped develop the heat shield designed to protect the shuttle as it reentered Earth’s atmosphere. NASA

The shuttle’s heat shield—composed mostly of delicate ceramic-coated tiles—presented so many unforeseen technological challenges that it delayed the launch of the spacecraft for years. NASA

To save money and time, Faget’s manned booster vehicle was eventually replaced by a pair of strap-on solid-fueled rockets, designed and constructed by the Thiokol Chemical Corporation. Here, a rocket is prepared for a test at the company firing range in Utah in 1979. NASA

The first three Black astronauts, photographed wearing the modified pressure suits similar to those worn in space shuttle flight tests, in 1979. Left to right: Ron McNair, Guion Bluford, and Fred Gregory. NASA

The first six women astronaut candidates gathered in the Public Affairs Briefing Room at the Johnson Space Center to meet the media on January 31, 1979. Left to right: Rhea Seddon, Anna Fisher, Judy Resnik, Shannon Lucid, Sally Ride, and Kathy Sullivan. NASA

Director of Flight Operations George Abbey, “the Thomas Cromwell of the Johnson Space Center” (second from left), the day before the first successful test flight of the Space Shuttle Columbia, in April 1981. With Abbey are (left to right) Columbia pilot Bob Crippen, Chief of Aircraft Operations Division Joseph Algranti, and astronaut Joe Engle. NASA

Columbia’s successful touchdown at Edwards Air Force Base in California on April 14, 1981. A crowd of 250,000 people stood in the desert to watch the triumphant return to Earth of the world’s first reusable spacecraft. NASA

James M. Beggs, appointed NASA chief by President Reagan shortly after the first shuttle flight in 1981. NASA

Bill Lucas, Director of NASA’s Marshall Space Flight Center in Huntsville, Alabama, oversaw the contractors’ design and construction of the Space Shuttle’s main engines and the solid rocket boosters. NASA

Chris Kraft (middle), Director of the Johnson Space Center in Houston, celebrates the completion of the second shuttle mission in November 1981. Beside him are Deputy Director of Flight Operations Gene Kranz (left) and Head of Structural Design Tom Moser (right). NASA

Public Affairs Officer and Chief Mission Control Commentator Steve Nesbitt (foreground) hosting a prelaunch press conference in Houston with the crew of mission STS-41-D before the maiden launch of the third shuttle orbiter, Discovery, in 1984. Behind Nesbitt (left to right) are astronauts Charlie Walker, Judy Resnik, Steve Hawley, Mike Mullane, Mike Coats, and Commander Hank Hartsfield. NASA

Booster Systems Engineer Jenny Howard was one of the few female flight controllers at NASA when the shuttle program began. She narrowly saved the shuttle from disaster during the launch of Challenger in July 1985. NASA

The second orbiter in the fleet, Challenger, on the launchpad at Cape Canaveral on January 26, 1983, during preparations for its maiden flight three months later. NASA

“One of the great mind-blowers of the 20th century.” Bruce McCandless II, flying free in space using the nitrogen-powered jetpack known as the Manned Maneuvering Unit on February 7, 1984. NASA

Judy Resnik during her first day in orbit aboard Discovery in 1984. Floating in the cockpit to her right is the clipboard she held up to the camera during a TV broadcast to Earth, showing a message to her father, Marvin: “HI DAD.” NASA

A weightless Ron McNair playing the saxophone during his first journey into space, aboard Challenger, in February 1984. McNair recorded three songs, including “What the World Needs Now Is Love,” in orbit—but all were accidentally deleted before the mission was over. NASA

Ellison Onizuka, photographed in his Air Force uniform soon after his promotion to lieutenant colonel, following his first journey into space as part of a three-day clandestine military mission aboard Discovery, in January 1985. National Archives

Dick Scobee in the cockpit of a two-seat biplane similar to the one he owned with fellow astronaut “Ox” van Hoften. June Scobee Rodgers

Mike Smith, photographed while lending a hand to his children’s lawn-care business, near the family home in Timber Cove. Smith Family Collection

Greg Jarvis, training for weightlessness aboard the “Vomit Comet” in January 1985; Jarvis would join the crew of mission 51-L only after being bumped from two earlier flight assignments. NASA

The unofficial “gag” portrait taken of the 51-L crew in late 1985, in honor of Christa McAuliffe, the Teacher in Space, and her backup, Barbara Morgan; Greg Jarvis had not yet been assigned to the mission. Clockwise from bottom left: Onizuka, Smith, McNair, McAuliffe, Morgan, Scobee, and Resnik. Smith Family Collection

Challenger after its rollout from the Vehicle Assembly Building to Pad 39B at Cape Canaveral, photographed on December 22, 1985. National Archives

The 51-L crew in the White Room beside Challenger during a break in the Terminal Countdown Demonstration Test—a final full-scale rehearsal for launch—on January 9, 1986. NASA

The five wives of the Challenger crew pose in front of the NASA plane that took them to the Cape, on January 23, 1986. Left to right: Cheryl McNair, Jane Smith, Marcia Jarvis, June Scobee, and Lorna Onizuka. Smith Family Collection

The crew of 51-L, accompanied by George Abbey and Chief of the Astronaut Office John Young, board the Astrovan for the short drive to the pad, on January 28, 1986. The final three frames shot by a NASA photographer outside the Operations and Checkout Building that morning, these are among the last photographs ever taken of the Challenger crew. National Archives

With less than nine minutes left in the countdown, family members of the crew gathered to watch the launch from the roof of the Launch Control Center. Challenger is visible in the distance, just over three miles away, on the far left of the photograph. Left to right: Scott Smith, Jane Smith, Erin Smith, Alison Smith, Marcia Jarvis, Kathie Scobee, June Scobee, and Rich Scobee. Smith Family Collection

From the ground, it was hard to tell immediately that anything had gone wrong. Alison Smith took this photograph around seventy-three seconds after launch. She turned to her brother and said, “Isn’t it beautiful?” Smith Family Collection

Morton Thiokol engineer Roger Boisjoly had called for a redesign of the joints in the solid rockets and tried to stop the Challenger launch the night before it happened. Here, he holds up a sample of the Viton O-rings used in the joint. Getty Images/Denver Post/Duane Howell

Allan McDonald being sworn in for his public testimony before the Rogers Commission on February 25, 1986. Thiokol’s chief representative at Cape Canaveral, McDonald refused to sign the company’s formal recommendation to launch. Getty Images/Bettmann

Larry Mulloy, NASA’s manager of the solid rocket booster project at the Marshall Space Flight Center, points to the O-ring in a full-size cross-section of the rocket joint during his testimony before the Rogers Commission on February 13, 1986. AP Images/Scott Stewart

Caltech professor Richard Feynman alienated some of his colleagues on the commission with what they saw as his publicity-seeking antics; but his ice-water “experiment” helped crystallize the role of the O-rings in the accident with the media. AP Images/Dennis Cook

In January 1987, NASA workers began lowering the recovered wreckage of Challenger into a pair of disused underground missile silos at Cape Canaveral Air Force Station, which were then locked and sealed with concrete caps. NASA