Knowles explains use of shuttle tragedy audio in 'XO'

Singer Beyonce Knowles has been slammed by some NASA astronauts and their families for using audio from the space shuttle Challenger disaster for her love song "XO". She has defended her decision by saying that it was recorded with the "sincerest intention".

"My heart goes out to the families of those lost in the Challenger disaster. The song 'XO' was recorded with the sincerest intention to help heal those who have lost loved ones and to remind us that unexpected things happen, so love and appreciate every minute that you have with those who mean the most to you," Knowles said in a statement, reports abcnews.go.com.

"The songwriters of "XO" included the audio in tribute to the unselfish work of the Challenger crew with hope that they will never be forgotten," she added.

Challenger exploded 73 seconds after liftoff from the Kennedy Space Center Jan 28, 1986. All seven crew members aboard were killed.

"Flight controllers here looking very carefully at the situation. Obviously a major malfunction," now retired NASA public affairs officer Steve Nesbitt had said.

Nesbitt's voice is heard after 27 years at the beginning of the video for Knowles' "XO", which is based on a troubled relationship. The audio clip lasts for six seconds.

NASA astronauts, employees and Challenger family members argue that using it in a pop song mocks the crew's sacrifice and opens fresh wounds.

Keith Cowing, a former NASA employee wants Knowles to remove the clip and apologise to families of the Challenger crew.