Wednesday marks 40 years Space Shuttle Challenger disaster

(NBC, KYMA) - Wednesday marks a somber anniversary in American history.

On this date 40 years ago in 1986, seven NASA astronauts were killed when Space Shuttle Challenger exploded during liftoff from Cape Canaveral.

One of the seven on board was school teacher Christa McAuliffe, who won a national competition to become the first civilian to travel into space on board the Challenger.

73 seconds after lift-off, the spacecraft exploded and broke apart as the launch was being broadcast live. There were no survivors.

In the aftermath of the disaster, an investigation concluded that the disaster was caused by the failure of an O-ring seal in one of the two solid-fuel rockets leading to the explosion.

The haunting image of the disaster is one that those who witnessed it live will never forget.

Another sad anniversary will be marked by nasa this coming Sunday.

On February 1, 2003, a second space-shuttle disaster rocked the country when Columbia disintegrated upon reentry into Earth's atmosphere.

All aboard that ship also perished.