The threats to the Earth’s population from objects that cross Earth orbit range from airbursts with localized damage to larger impacts with global consequences. The Origins Spectral Interpretation Resource Identification Security Regolith Explorer (OSIRIS-REx) spacecraft will arrive in 2018 at one of the most potentially Earthhazardous asteroids known—near-Earth carbonaceous asteroid 101955 (1999 RQ36,) and return to Earth with a sample in 2023. Planetary defense against these Near-Earth Objects (NEOs) involves both detection and mitigation, where mitigations fall into three categories: civil defense warning, low-energy deflection, and highenergy deflection. Based on OSIRIS-REx mission design analysis, low-energy deflection missions require the tools and time to identify spacecraft hazards, know the gravity field to design mission-compatible stable orbits, and perform proximity operations. High-energy deflection with a kinetic-energy impactor requires tools to acquire the object and maneuver updates with on-board guided navigation. In addition to the low-energy deflection needs, high-energy deflection with explosives requires on-board guided navigation and tools to place an object in proximity to the NEO (standoff explosion), on the surface or into a crater formed by a kineticenergy impactor mission. Each deflection mission also requires the means to verify the success of the deflection by measuring the change in the NEO’s orbit and tracking fragments > 30-m in diameter. The OSIRIS-REx mission provides valuable insights into Planetary Defense spacecraft engineering and mission design in addition to performing its primary objective of collecting scientific data about the Solar System’s most primitive objects.
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