[2][3] The fourth stage is an Orbital Adjustment Module, fueled by hydrazine and propelled by four MR-107 engines, which is used for final insertion.

Its maiden flight was conducted from LC-46 at Spaceport Florida, and lifted off at 02:28 GMT on 7 January 1997.

The next Athena II launch took place from SLC-6 at Vandenberg on 27 April 1999, with the Ikonos satellite for Space Imaging.

The launch ended in failure after the payload fairing failed to separate, and as a result the rocket had too much mass to achieve orbital velocity.

The payload, Ikonos 1, was also for Space Imaging, and successfully reached orbit.