In September 2006, it was announced that the final stage of testing on the Ariane 5's customised ATV stage was within its final phase. In December 2006, it was announced that the first ATV had completed its vacuum test, marking the successful completion of the key tests and enabling a final launch date to be set. In April 2007, the ATV was subject to four-month long qualification process in response to operational concerns, including safety queries originating from the U.S., and to examine the vehicle's potential commercialisation.