When the Space Shuttle Challenger exploded on take-off on 28 January 1986, millions of Americans became bound together in a single, historic moment. Many still vividly remember exactly where they were and what they were doing when they heard about the tragedy.
The shuttle exploded seconds after lift-off, killing its crew of seven. Among them was Christa McAuliffe, a school teacher selected as the first to fly in the “citizen in space” programme.
Her husband and children, along with the families of other astronauts, witnessed the disaster.
Challenger was 72 seconds into its flight, travelling at nearly 2,000 mph at a height of ten miles, when it was suddenly enveloped in a red, orange and white fireball as thousands of tons of liquid hydrogen and oxygen fuel exploded.
Photographs taken by chase planes reveal that there was a prelude: a small tongue of flame appeared on one of the external booster rockets soon after lift-off and was quickly followed by another.
Then a halo of flame grew round the base of the booster just before the explosion. However the crew reported nothing abnormal.
The flight had been postponed five times, three of them because of bad weather, and the temperature the last night was below freezing.
The tragedy dealt a devastating blow to the shuttle programme, already in difficulties because of cost overruns.
These were the first American fatalities in space, though three astronauts died in a launch pad fire in 1967.
Journalists and investigators have historically cited production problems and managerial wrong-doing as the reasons behind the disaster.
The subsequent Presidential Commission uncovered a flawed decision-making process at the space agency as well, citing a well-documented history of problems with the O-ring and a dramatic last-minute protest by engineers over the Solid Rocket Boosters as evidence of managerial neglect.