Today is a somber day for NASA. The space agency marks the 50th anniversary of the Apollo 1 disaster, which claimed the lives of three astronauts who were slated to test out technologies needed to eventually land on the Moon. During a launch rehearsal on January 27th, 1967, Virgil "Gus" Grissom, Ed White, and Roger Chaffee were killed after a fire broke out in the cabin of the spacecraft they had been training in. It was a tragedy that forever changed how NASA handled safety protocols surrounding human spaceflight.

On this particularly weighted anniversary, the space agency is opening a new tribute exhibit at NASA’s Kennedy Space Center in Florida to commemorate the lives of the three astronauts lost in Apollo 1. Called "Ad Astra Per Aspera - A Rough Road Leads to the Stars,” the exhibit showcases items that tell the story of the astronauts’ lives, as well as the story of the fire and its effects on the space agency. The families of the fallen astronauts have also given their blessing to the exhibit, according to NASA.

"Ultimately, this is a story of hope, because these astronauts were dreaming of the future that is unfolding today," former astronaut Bob Cabana, center director at Kennedy Space Center, said in a statement. "Generations of people around the world will learn who these brave astronauts were and how their legacies live on through the Apollo successes and beyond."

Today’s anniversary also kicks off a hard week for NASA. Tomorrow marks the anniversary of the Space Shuttle Challenger disaster, in which the vehicle burst apart during launch. The lives of all seven crew members on board were lost in the accident. Then, the anniversary of the Space Shuttle Columbia accident is on February 1st. Columbia broke apart during reentry in Earth’s atmosphere, also leading to the deaths of its seven crew members. NASA commemorated all three tragedies yesterday during its annual Day of Remembrance.