Columbia tragedy anniversary marked
Nasa is set to honour the seven astronauts who perished when the space shuttle Columbia was destroyed 10 years ago.
The US space agency will mark the anniversary at a public memorial service at Kennedy Space Centre in Florida.
Speakers include Evelyn Husband Thompson, who was married to the shuttle's commander, Colonel Rick Husband.
The accident on February 1 2003 killed six Americans as well as Israel's first astronaut, Ilan Ramon. They were returning home from a 16-day science mission when the shuttle disintegrated over Texas, just minutes from landing in Florida.
An investigation board later attributed the cause to damage to the wing which was sustained during lift-off.
The shuttles were grounded for more than two years, and resumed flying with more safety features in place before they were retired in 2011.