LOS ANGELES — Iridium Communications says its next two launches of new-generation satellites will use refurbished SpaceX Falcon 9 first-stage boosters that have flown previously.

The announcement Thursday is another step in SpaceX’s effort to reduce launch costs.

The company has launched a few used boosters and is trying to expand acceptance of reusability across the industry.

Hawthorne, California-based SpaceX has had successful landings of Falcon 9 first stages after launches from both coasts.

Iridium is in the midst of seven launches to replace its satellite fleet that provides global mobile voice and data communications.

The McLean, Virginia, company says insurers confirmed there is no increase in premiums for “flight-proven” rocket use.

Thirty new satellites are in orbit and the fourth launch is scheduled for Dec. 22 at Vandenberg Air Force Base, California.