Rocket "anomaly" at Cape Canaveral

The explosion of this Delta-2 rocket shortly after liftoff was spectacular, and no doubt created a serious challenge for the fire department. It is unclear when this happened, but the video was uploaded to YouTube on June 17, 2006.

The narrator describes the explosion as an "anomaly". How would you describe it?



The cause was a 17-foot long crack in one of the rocket boosters. An no one noticed a 17-foot long crack before launch?