Remembering Challenger: NASA Marks 25 Years Since Space Tragedy

An official portrait shows the STS-51L crewmembers. Back row (L to R): Mission Specialist, Ellison S. Onizuka, Teacher in Space Participant Sharon Christa McAuliffe, Payload Specialist, Greg Jarvis and Mission Specialist, Judy Resnik. Front row (L to R): Pilot Mike Smith, Commander, Dick Scobee and Mission Specialist, Ron McNair.

(By Clara Moskowitz, FoxNews.com) - NASA commemorated three space tragedies this week, which also marked the 25th anniversary of the shuttle Challenger accident that killed seven astronauts. The space agency also paused to remember the 2003 loss of the shuttle Columbia and its crew and the earlier Apollo 1 fire that killed three astronauts.

The explosion as seen live on CNN:



Rarely seen home video of the explosion from a different angle:



President Reagan addresses the nation: