The U.S. Air Force has announced that Lockheed Martin, Orbital Sciences and Space Exploration Technologies are all eligible to compete in the Orbital/Suborbital 3 (OSP-3) launch program.

The three were picked to bid for launches under the indefinite-delivery/indefinite-quantity OSP-3 contract, which has a ceiling of $900 million worth of work through 2017.

Through this contract, the companies are expected to win launches to showcase the capabilities of their new rocket designs, and potentially earn certification criteria toward eventually competing against United Launch Alliance’s Delta IV and Atlas V, which now enjoy a monopoly for large-payload-class government launches.

Lockheed is pushing its Athena rocket, Orbital is proposing its new Antares and existing Minotaur family, and SpaceX will offer its Falcon 9.