** ADVANCE FOR USE FRIDAY, JAN. 28, 2011 AND THEREAFTER ** FILE - In this Jan. 28, 1986 file photo, the space shuttle Challenger explodes shortly after lifting off from the Kennedy Space Center in Cape Canaveral, Fla. (AP Photo/Bruce Weaver, File)
CNN  — 

Thirty-four years ago, NASA experienced an in-flight tragedy when the space shuttle Challenger broke apart shortly after launch, killing all seven crew members aboard.

Taking off from the Kennedy Space Center in Cape Canaveral, Florida, the cold weather conditions that morning combined with a design flaw led to a rocket booster failure and caused a structural collapse.

The Space Shuttle Challenger was the world's first partially reusable launch vehicle.

The external fuel tank collapsed due to a leak in the shuttle’s right solid rocket booster joint, which released liquid hydrogen and liquid oxygen propellants and ignited to create a giant fireball, which made it appear as if the Challenger had exploded.

Allan McDonald, director of the Space Shuttle Solid Rocket Motor Project for the engineering contractor Morton Thiokol, refused to sign a launch recommendation for the Challenger the night before over safety concerns.

The space shuttle Challenger appeared to have exploded after a fireball ignited.

The Challenger broke apart 73 seconds after launch at approximately 11:40 a.m. ET on January 28, 1986.

The launch and subsequent explosion was aired live on CNN and was watched in classrooms across the US that morning. NASA had a special satellite broadcast set up for schools across the nation to watch what was supposed to be a historic moment.

NASA set up a live satellite feed of the Space Shuttle Challenger launch.

Christa McAuliffe, a high school teacher from New Hampshire, was supposed to be the first civilian and American teacher in space. She was selected as part of the Teachers in Space program.

Space Shuttle Challenger crew members: Mission specialist Ellison S. Onizuka, Teacher-in-Space participant Sharon Christa McAuliffe, payload specialist Greg Jarvis and mission specialist Judy Resnick. Pilot Mike Smith, commander Dick Scobee and mission specialist Ron McNair.

She would join commander Francis R. Scobee; pilot Michael J. Smith; payload specialist Gregory Jarvis; and mission specialists Ronald McNair, Ellison Onizuka and Judith Resnik to make up the crew of Mission STS-51L.

The disaster grounded NASA’s space shuttle program for nearly three years.

Military guards transfer caskets bearing remains of Challenger's crew, which exploded after liftoff.

Every year, NASA holds a “Day of Remembrance” to honor fallen astronauts. It began after the space shuttle Columbia disaster, which claimed the lives of its seven-member crew during its return to Earth on February 1, 2003.

There is a Space Shuttle Challenger memorial at Arlington National Cemetary in Virginia.