The space shuttle Challenger's mission in 1986 was meant to mark a milestone in spaceflight: the first orbital voyage of an American teacher. NASA's choice for the honor was Christa McAuliffe, a social studies teacher at Concord High School in New Hampshire.
Here, McAuliffe rides past the New Hampshire State House in Concord with her daughter Caroline and son Scott, during a Lions Club parade on July 21, 1985.
— Jim Cole / AP
The crew of the space shuttle Challenger, from left: Ellison Onizuka, Mike Smith, Christa McAuliffe, Dick Scobee, Greg Jarvis, Ron McNair and Judy Resnick.
— Courtesy of NASA
The shuttle Challenger lifts off from the Kennedy Space Center on Jan. 28, 1986.
Classmates of the son of America's first teacher-astronaut cheer as Challenger lifts off.
The boy in the white hat and glasses at center is Peter Billingsley, the star of "A Christmas Story" and a spokesman for the young astronaut program.
— JIM COLE / AP, file
The space shuttle Challenger exploded 73 seconds into flight.
The shuttle’s fuel tank tore apart, spilling liquid oxygen and hydrogen, which formed a huge fireball at an altitude of 46,000 feet.
Earth is seen from the space shuttle Columbia's flight deck on Jan. 22, 2003.
This picture of Columbia's crew was on a roll of unprocessed film recovered from the debris after the space shuttle disintegrated. The crewmembers struck a "flying" pose for their traditional in-flight crew portrait in the Spacehab research module.
From left, bottom row, are Kalpana Chawla, commander Rick Husband, Laurel Clark and Ilan Ramon. In the top row are David Brown, William McCool and Michael Anderson.
Debris from the space shuttle Columbia streaks across the sky over Tyler, Texas, on Feb. 1, 2003.
Columbia broke apart at an altitude of about 200,000 feet over Texas, killing all seven astronauts just minutes before they were slated to land in Florida.
— Scott Lieberman / AP
A small brush fire burns after being ignited by debris from the Columbia accident outside Athens, Texas. The shuttle's wreckage was scattered over a five-state area.
NASA's Kennedy Space Center stores about 84,000 pounds of debris from the space shuttle Columbia, representing 40 percent of the spacecraft. The space agency occasionally loans out pieces for engineering research.
Vice President Mike Pence walks with June Scobee-Rodgers, widow of Challenger Commander Dick Scobee to see the Challenger memorial during the NASA Day of Remembrance ceremony at Arlington National Cemetery on Feb. 7, 2019.