SpaceX rocket launched from California has successfully deployed five communications satellites, reusing part of a previously flown rocket for its 10th mission of 2018.

The Falcon 9 rocket lifted off from Vandenberg Air Force Base on California’s central coast about 12:47 p.m. local time Tuesday.

The deployment of the commercial Iridium Communication’s satellites Tuesday followed the release of a pair of U.S.-German science satellites. Called GRACE-FO, for short, the mission will detect the movement of Earth’s water masses and changes in mass within the planet by measuring variations in gravity through tiny fluctuations in the distance between the two satellites as they orbit 137 miles (220 kilometers) apart—roughly the distance between Los Angeles and San Diego—at an altitude of about 304 miles (490 kilometers).

Reusable rocket components are crucial to SpaceX’s strategy to drastically reduce the cost of space travel. SpaceX is targeting roughly 30 missions this year, up from a record 18 in 2017.