Next week will use a previously-flown Falcon 9 booster, and the final two Iridium Next missions will fly on new Block 5 boosters.
This would be the tenth launch for SpaceX in 2018.
Iridium Next 51-55 & GRACE Follow-On
Launch time: 1947:58 GMT (3:47:58 p.m. EDT; 12:47:58 p.m. PDT)
Launch site: SLC-4E, Vandenberg Air Force Base, California