Sources: 

SpaceX's NROL-172 mission, targeted for liftoff at
7:13 p.m. PDT on Monday, is a significant step in advancing the National Reconnaissance Office's intelligence-gathering capabilities. This launch from
Vandenberg Space Force Base marks the agency's 13th mission related to its
proliferated architecture of satellites.
The NROL-172 mission aims to establish a constellation of satellites that improves
revisit rates and coverage, effectively mitigating risks associated with single points of failure. The satellites will comprise electro-optical, radar, and relay capabilities, as outlined by the mission objectives.
The mission utilizes a
Falcon 9 rocket, marking its second flight under the
National Security Space Launch (NSSL) Phase 3 Lane 1 contract managed by the United States Space Force's Space Systems Command.
A live webcast will commence 10 minutes before the launch. If necessary, a backup launch opportunity is available the following day, starting at
3:15 p.m. Tuesday.
Ensuring safe observation, officials advise the public about viewing locations near
Harris Grade Road and Vandenberg Village, reinforcing safety protocols during the launch event.
The success of NROL-172 will pave the way for future missions that support the NRO’s expanded satellite constellation efforts.
Sources: 
SpaceX is preparing to launch the NROL-172 mission for the National Reconnaissance Office from Vandenberg Space Force Base, targeted for 7:13 p.m. PDT on Monday. This mission is part of a broader initiative to enhance intelligence-gathering capabilities through a constellation of satellites.