Tuesday marks the 28th anniversary of the space shuttle Challenger tragedy, an event that resulted in the death of seven crew members and a 32-month hiatus in NASA's shuttle program.

On Jan. 28, 1986, the spacecraft broke apart 73 seconds after launch due to a booster engine failure, killing Michael J. Smith, Dick Scobee, Ronald McNair, Ellison Onizuka, Christa McAuliffe, Gregory Jarvis and Judith Resnik.

McAuliffe wasn't an astronaut by profession, but a school teacher who beat out more than 11,000 applicants to win a trip into space aboard the shuttle. Her involvement meant students throughout the country were among those to witness the event live.

"It was just a shock," Frances VanKulick, who watched the event from her front yard in Melbourne, Fla., told the Huffington Post. "I didn't know what to think, because we saw parts falling down from the shuttle and we had to wait until the TV gave us the report of what had happened."

That night, VanKulick attended a vigil on the beach for those who had died.

"It stays with you," she said. "It's something you never forget."

In his address to the nation, Ronald Reagan made a point to address the younger generation directly.

"And I want to say something to the schoolchildren of America who were watching the live coverage of the shuttle's take-off," he said. "I know it's hard to understand, but sometimes painful things like this happen. It's all part of the process of exploration and discovery. It's all part of taking a chance and expanding man's horizons. The future doesn't belong to the fainthearted; it belongs to the brave. The Challenger crew was pulling us into the future, and we'll continue to follow them."

Other US space crews who sacrificed their lives include Apollo I's Virgil Grissom, Edward White and Roger Chaffee, who died in 1967 during a pre-flight test, and the 2003 Columbia crew, who died when the spacecraft disintegrated upon reentry. Those who died in the Columbia disaster were Laurel Blair Salton Clark, Kalpana Chawla, David Brown, Rick Husband, William McCool, Michael Anderson and Ilan Ramon.