SpaceX is targeting launch of Iridium-6/GRACE-FO on Tuesday, May 22 from Space Launch Complex 4E (SLC-4E) at Vandenberg Air Force Base, California. The instantaneous launch opportunity is at 12:47 p.m. PDT, or 19:47 UTC. The GRACE-FO satellites will be deployed approximately eleven minutes and thirty seconds after launch, followed by the deployment of five Iridium® NEXT satellites beginning about an hour after launch. A backup instantaneous launch opportunity is available on Wednesday, May 23 at 12:42 p.m. PDT, or 19:42 UTC. Falcon 9’s first stage for the Iridium-6/GRACE-FO mission previously supported the Zuma mission from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station in January 2018. SpaceX will not attempt to recover Falcon 9’s first stage after launch.