Seven astronauts died after NASA space shuttle crashed in 2003

Two decades ago the US space shuttle Columbia broke up as it returned to Earth, killing the seven astronauts on board. NASA suspended space shuttle flights for more than two years as it investigated the cause of the disaster. It was the second such tragedy following the explosion of the Challenger space shuttle in 1986, just one minute after takeoff. Yasmine El-Sabawi looks back at what happened to the Columbia, and the lessons that were learned.