NEO Surveyor is the flight mission which originated from the NEOCam mission proposed by Dr. Amy Mainzer to the Discovery Program in 2014. NEOCam was approved for Extended Phase A study to further refine the technical design and perform risk reduction activities. The Extended Phase A completed System Readiness Review / Mission Design Review in February 2018, and a pre-KDP-B review for the instrument development effort in November 2018.
In November 2019, NEOCam was retired and the NEO Surveyor was directed to begin formulation efforts. It became a directed mission with planetary defense objectives only. The NEO Surveyor directly addresses the 2005 Congressionally mandated George E. Brown, Jr. Near-Earth Object Survey Act (PDF) and the 2010 National Research Council report "Defending Planet Earth: Near-Earth-Object Surveys and Hazard Mitigation Strategies."
The NEO Surveyor has a flight segment, the NEO Surveyor, and a ground segment, the NEO Surveyor Investigation System. The NEO Surveyor Project will design, build, test, and operate these two systems together optimized in sensitivity, observation cadence, and data analysis pipeline to find and characterize these potentially hazardous objects. NEO Surveyor is a Category 2 mission per NASA Procedural Requirements (NPR) 7120.5E and Risk Classification C per NASA Program Directive (NPD) 8705.4.
The biggest difference between NEOCam and NEO Surveyor, besides the new focus on planetary defense, is that NEO Surveyor added University of Arizona as a technical partner. Dr. Amy Mainzer is now at the University of Arizona and is the NEO Surveyor Survey Director. Dr. Mainzer leads the UA team, who is responsible for Focal Plane Mosaic work, the Investigation Team and the NEO Surveyor Investigation Software Suite, and overall NEO Surveyor project management.