A pair of spy satellites launched on June 15 atop an Atlas V rocket were placed into the wrong orbit, according to Aviation Week & Space Technology.

The top secret satellites separated safely from the malfunctioning booster, however, and have enough rocket propellant to continue their mission, an official said on background.

The U.S. Air Force, which managed the Atlas V launch, and the NRO have begun an official investigation into the launch and malfunction. The $83 million Atlas V used in the launch is a model 401 with no solid rocket boosters.

"The Atlas V people have a lot of explaining to do," the official said on background. The flight was the first NRO secret mission for the new Atlas V Evolved Expendable Launch Vehicle.