Workers prepare one of three United Launch Alliance Delta II rocket motors at Vandenberg Air Force Base in California.

Workers prepare one of three United Launch Alliance Delta II solid rocket motors for its lift into the service tower at NASA's Space Launch Complex-2 (SLC-2) at Vandenberg Air Force Base in California.

Following final tests, the spacecraft will be integrated to the Delta II in preparation for the targeted June launch. Aquarius, the NASA-built instrument on the SAC-D spacecraft will provide new insights into how variations in ocean surface salinity relate to fundamental climate processes on its three-year mission. Photo credit: NASA/VAFB