It has been nearly three decades since the space shuttle orbiter Challenger exploded just 73 seconds after lifting off from Cape Canaveral, Florida, on January 28, 1986. More than 12 years have passed since the February day in 2003, when another space shuttle, Columbia, disintegrated upon re-entry into Earth’s atmosphere. This summer, pieces of the wreckage as well as personal effects of the 14 astronauts killed aboard the two doomed shuttles are on display for the first time, as part of a new permanent memorial at NASA’s Kennedy Space Center.

When the space shuttle Challenger lifted off on its 10th mission on January 28, 1986, its crew of seven included New Hampshire schoolteacher Christa McAuliffe, winner of a national competition designed to highlight the importance of teachers and foster students’ interest in space and other high-tech careers. Countless schoolchildren were among the TV viewers watching in horror as the space shuttle exploded into pieces when a booster engine failed just 73 seconds after liftoff from Cape Canaveral. In the aftermath of this tragedy, the National Aeronautics and Space Administration (NASA) conducted an intensive investigation to determine what had gone wrong, and to make the shuttle program safer for its astronauts. The 118 tons of wreckage, salvaged from the Atlantic Ocean, was then buried in a pair of abandoned missile silos some 90 feet below ground, far from the public eye.

The tragedy that claimed the space shuttle Columbia on February 1, 2003, occurred just minutes before a planned landing at Cape Canaveral’s Kennedy Space Center after a 16-day mission. Columbia, which had made the shuttle program’s first flight in 1981, was reentering Earth’s atmosphere at the end of its 28th mission when it disintegrated into pieces, raining debris over eastern Texas. A subsequent investigation determined that a piece of insulating foam had broken loose and struck the shuttle’s left wing during launch. During reentry, hot gases penetrated the damaged section and melted parts of the wing, which eventually collapsed.

In contrast to the highly out-of-the-way storage of the Challenger debris, NASA kept the 42 tons of Columbia debris in its Vehicle Assembly Building at Kennedy, making it available for research purposes. On the fifth anniversary of the tragedy in 2008, the wreckage was included in a traveling in-house exhibit, aimed at providing safety reminders for its workforce.

After NASA ran its last space shuttle mission in 2011, it made the decision to keep Atlantis—which flew that final mission—at the launch site at Kennedy, making the retired spacecraft the centerpiece of a public display dedicated to the space shuttle program. This summer, as part of the larger exhibit, NASA unveiled a permanent memorial called “Forever Remembered,” dedicated to the Challenger, the Columbia and the 14 astronauts who lost their lives during the two shuttles’ final missions.

The new memorial marks the first time in history that artifacts from the Challenger and Columbia have been on public display. The 2,000-square-foot exhibit includes one piece of debris from each shuttle and a display case for each astronaut, housing items contributed by their families as well as some that were in NASA’s possession. In a dimly lit room, a 2-foot section of the left side body panel of Challenger is displayed vertically, with a battered U.S. flag still attached. Nearby are the scorched frames of the Columbia’s cockpit windows, placed at eye level so they appear to be floating in midair.

Among the personal effects featured in the memorial is a leather helmet that belonged to Challenger commander Francis “Dick” Scobee, who used it when he flew a Starduster biplane with his wife, June. Visitors will also find a pair of scuffed cowboy boots and a Bible belonging to Columbia commander Rick Husband, along with a vintage Star Trek lunch box owned by Michael Anderson, payload commander on the Columbia flight. Not all of the astronauts’ families chose to participate; Christa McAuliffe’s was among those who did not. The schoolteacher’s display case includes a NASA “Teacher in Space” patch and a quote from her: “I touch the future. I teach.”

The exhibit aims to show how the astronauts lived, and not how they died, and its organizers deliberately chose not to display any images of the shuttles breaking apart in the air. As Michael Ciannilli, the shuttle engineer and test director at NASA who took charge of the Challenger and Columbia debris on display, told the Associated Press of the decision not to focus on the space shuttles’ final moments: “There’s more to this story….Great pains were taken not to have anything sensationalized or exploited.”