33rd year anniversary of Space Shuttle Challenger explosion

[gtxvideo vid=’IehFj4lw’ thumb=’http://player.gtxcel.com/thumbs/IehFj4lw.jpg’ vtitle=’space challenger’]

(ABC NEWS) – Today marks the 33-year anniversary of the space shuttle challenger that exploded.

The tragedy happened 73 seconds after lift-off.

Astronaut, Ron McNair was among those killed.