"The future doesn't belong to the fainthearted; it belongs to the brave," President Ronald Reagan told the nation 25 years ago following the explosion of the Challenger space shuttle, just 73 seconds into its launch. "The Challenger crew was pulling us into the future, and we'll continue to follow them."
Over two decades later, the memory of the mission's catastrophic end--and the jarring scene, witnessed by so many students and citizens, of the shuttle's explosion--remains present and painful.
NASA held a memorial at the launch site in Cape Canaveral, Florida to honor the Challenger's seven crew members, including schoolteacher and citien Christa McAuliffe, who perished in the space shuttle's explosion, as well as the "fallen explorers" on board the Apollo 1 and Columbia.
"This year marks the 25th anniversary of the loss of Challenger -- a tragedy that caused us to completely re-think our systems and processes as we worked to make the shuttle safer," NASA administrator Charles Bolden said in a statement. "The legacy of those who have perished is present every day in our work and inspires generations of new space explorers."
HuffPost readers shared their memories of the Challenger explosion on Twitter, recalling where they were, and how they felt, when they first learned of the shuttle's calamity. See their remembrances below, and add your own using the hashtag #ChallengerMemory. Read Reagan's speech and see images of the Challenger's launch.