Speaker
Description
Keywords: Planetary Defense, Flyby, Spacecraft Reconnaissance, Near-Earth Object
International and U.S. strategies have identified the need to develop spacecraft reconnaissance capabilities as a priority to advance planetary defense readiness. The UN-endorsed Space Mission Planning Advisory Group and the US Report on Near-Earth Object Impact Threat Emergency Protocols recommend planning a spacecraft reconnaissance mission in any scenario where 1) Earth impact is predicted to be within <50 years, 2) impact probability is assessed to be >1%, and 3) the object is characterized to be >50 m in size (or absolute magnitude (H) of <26). Given these thresholds, the 2023 U.S. Decadal Survey for Planetary Science and Astrobiology recommended that the highest priority for the next planetary defense demonstration mission is a rapid-response, flyby reconnaissance mission targeted to a small NEO as a challenging case for the capability. The 2023 U.S. National Preparedness Strategy and Action Plan for Near-Earth Object Hazards and Planetary Defense and the 2023 NASA Planetary Defense Strategy and Action Plan both identify the short-term action of planning for the development, testing, and implementation of NEO reconnaissance mission systems.
To develop a robust flyby reconnaissance capability for planetary defense, we have developed four major requirements to define a demonstration mission:
1) Enable a flyby of >90% of the potential asteroid threat population – our analysis shows that flyby speeds of up to 25 km/s and approach solar phase angles as high as 90° have to be accommodated within the mission’s capabilities to meet this requirement.
2) Demonstrate the flyby reconnaissance for a ~50 m NEO – 50-m objects are the smallest recommended for a space-based response, providing the stressing case for the capability.
3) Obtain the information needed to determine if and where it would impact the Earth – planning for a reconnaissance mission is recommended if Earth impact is >1%, and hence determining if the object will impact the Earth and if so, constraining the impact swath location on the planet, is a top priority.
4) Determine key properties of the asteroid to inform decision makers – While in any threat situation, as much information as possible is always desired, our analysis identifies four key properties that are the priorities: size, rocky vs. metallic composition, single vs. multiple objects, and surface characteristics.
Applying this capability to the 2025 PDC Hypothetical Asteroid Impact Scenario, which has crossed the recommended thresholds for mission planning, we show how the data obtained by the flyby reconnaissance we have defined would greatly increase the knowledge of the potential threat to inform the subsequent planetary defense response.