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[[Image:Space Shuttle Challenger Crew.jpg|thumb|right|300px|The Space Shuttle Challenger crewmembers are: in the back row from left to right: Mission Specialist, Ellison S. Onizuka, Teacher in Space Participant Sharon Christa McAuliffe, Payload Specialist, Greg Jarvis and Mission Specialist, Judy Resnik. In the front row from left to right: Pilot Mike Smith, Commander, Dick Scobee and Mission Specialist, Ron McNair.]]

[[Image:Space Shuttle Challenger Crew.jpg|thumb|right|300px|The Space Shuttle Challenger crewmembers are: in the back row from left to right: Mission Specialist, Ellison S. Onizuka, Teacher in Space Participant Sharon Christa McAuliffe, Payload Specialist, Greg Jarvis and Mission Specialist, Judy Resnik. In the front row from left to right: Pilot Mike Smith, Commander, Dick Scobee and Mission Specialist, Ron McNair.]]

The '''Space Shuttle Challenger''' disintegrated due to O-ring failure 73 seconds after lift-off on January 28, 1986, killing all seven members on board.  Those killed included the first private citizen to fly on a [[space shuttle]], who was a high school teacher.<ref>http://www.fas.org/spp/51L.html</ref>

The '''Space Shuttle Challenger''' disintegrated due to O-ring failure 73 seconds after lift-off on January 28, 1986, killing all seven members on board.<ref>https://history.nasa.gov/Biographies/challenger.html</ref> Those killed included the first private citizen to fly on a [[space shuttle]], who was a high school teacher.<ref>http://www.fas.org/spp/51L.html</ref>

President [[Ronald Reagan]] mourned the tragedy in an address to the [[United States of America|nation]]:

President [[Ronald Reagan]] mourned the tragedy in an address to the [[United States of America|nation]]: