Launching a space shuttle 150 miles in outer space is tricky business. The Challenger shuttle weighed in at near 270,000 pounds, requiring over two million pounds of solid fuel to launch. Needless to say, in an undertaking of such enormous complexity, even a single unaccounted factor can jeopardize the whole launch — a problem that actually happened with Challenger space shuttle just seconds after takeoff.On this day, January 28, 1986, after days of delay due to mechanical problems and inclement weather, the Challenger space shuttle exploded shortly after liftoff. Photographic evidence, which was studied at some length in the subsequent investigations, revealed a leak from the right solid rocket booster carrying the shuttle half a second after liftoff. The hot gases from the booster breached the shuttle’s main fuel tank, and 73 seconds after launch, the space shuttle exploded from the inside out.

As the investigation panel set up by President Regan revealed, NASA had been aware for some time of the possibility of fuel leaks in the rocket boosters. The O-ring joint problem was discovered by NASA and engineering contractor Morton Thiokol as far back as 1977, but both decided to do nothing, accepting the possibility of an explosion from the faulty part as just another flight risk. The weather, too, might have played a part in the accident: temperatures at the time of the launch were just below freezing, the coldest in the history of space shuttle launches. NASA admitted in the subsequent investigation they had no idea how that might have changed the launch dynamics.