After suffering a series of mainly weather related launch delays over previous days, an Atlas V 421 operated by the United Launch Alliance (ULA) successfully launched a military satellite at 0728 on 15 October 2017 from its launch pad at the the Cape Canaveral air station in Florida.
The circa five metric ton NRO-L52 spacecraft carried was officially for the National Reconnaissance Office. It is thought to be a QUASAR 4 data relay satellite as part of the SDS system (the spacecraft is informally known as SDS-4 2) used by the US military which will operate in the geosynchronous orbit some 36,000 km above the equator. In that role, the system relays images and other day mainly from imaging and radar spacecraft in other lower orbits (usually Sun-synchronous low Earth orbits).