Looking back on the 30th anniversary of the space shuttle's explosion
                                
                                
                                    (Newser) -
                                    Thirty years ago, the  space shuttle Challenger exploded  after liftoff, killing all seven people onboard—including high-school teacher Christa McAuliffe. The 25th flight for NASA's space shuttle program was to have studied Halley's Comet and deployed two satellites,  Discovery News  reports; McAuliffe was to have taught science lessons...