The NEO Surveyor planetary defense mission is made up of 5 parts:

1. Launch – NEO Surveyor will launch around September 2027.
2. In-Orbit Checkout – In the first 30 days, NEO Surveyor will perform in-orbit checkouts while it travels to its destination, a region of space fairly close to the Earth (in astronomical terms) called the Earth-Sun L1 Lagrange point, similar to where the SOHO and Genesis missions operated.  Here it will take on a large-amplitude “halo” orbit.  This vantage point at L1, which is about four times further away than the Moon and interior to the Earth along the Earth-Sun line, allows NEO Surveyor to view a large fraction of the Earth’s orbit at any given time, and the sunshade (based on the 1983 IRAS mission) allows it to look close to the Sun.  This region of space is ideal for NEO Surveyor, allowing the observatory to maintain a nearly constant distance from Earth (about 1 million kilometers) – far enough away to provide a stable, cold environment, yet close enough to support the high-speed radio communications needed to send NEO Surveyor’s large-format images back to Earth.  NEO Surveyor’s orbit is carefully designed to maximize scientific discovery while minimizing cost, complexity, and risk. 
3. Survey Verification — The science phase starts 30 days after launch.  By this time, NEO Surveyor has traveled most of the distance to L1.  All observatory operations follow the science phase protocols.  A 6-month survey verification period allows exploratory data to be collected and calibrations to be performed by the mission’s ground segment in order to optimize object detection.  At the same time, NEO Surveyor is finding, tracking and characterizing near-Earth objects.
4. Nominal Survey – NEO Surveyor performs a continuous, repetitive survey for at least 56 more months (12 years total being the goal), with scheduled breaks for telecommunication and momentum management tasks.  In the first 5 years of survey operations, NEO Surveyor will find more than 2/3 of near-Earth objects >=140 m diameter in size.
5. Decommissioning – At mission end (62 months to 12 years after launch), NEO Surveyor will retire and transition to a heliocentric orbit.

NEO Surveyor’s Viewing Geometry – NEO Surveyor’s location inside the Earth’s orbit and unique ability to survey for asteroids as close as 45 degrees to the sun means that it can cover a much larger fraction of the region of space where hazardous asteroids are located. Over the course of 4 years, approximately two-thirds of all potentially hazardous asteroids will pass within this viewing window and be observed, detected, and reported by NEO Surveyor. (Image credit: NASA/JPL-Caltech)