Space Mission Options for Reconnaissance and Mitigation of Asteroid 2024 YR4 Authors: Brent W. Barbee, Matthew A. Vavrina, Rylie Bull, Adrienne Rudolph, Davide Farnocchia, Russell TerBeek, Justin Atchison, Joshua Lyzhoft, Jessie Dotson, Patrick King, Paul W. Chodas, Dawn Graninger, Ronald G. Mink, Kathryn M. Kumamoto, Jason M. Pearl, Mary Burkey, Isaiah Santistevan, Catherine S. Plesko, Wendy K. Caldwell, Megan Harwell Submitted: 15 September 2025 Subject areas: Instrumentation and Methods for Astrophysics; Earth and Planetary Astrophysics; Space Physics Published: Submitted to the Journal of the Astronautical Sciences arXiv ID: 2509.12351 --- Abstract Summary Near-Earth asteroid 2024 YR4 was discovered on 27 December 2024. Its probability of impacting Earth peaked at about 3% on 18 February 2025, but additional observations ruled out Earth impact by 23 February 2025. After Earth impact was ruled out, the chance of a lunar impact rose, reaching about 4% by May 2025. Observations by the James Webb Space Telescope (JWST) on 26 March 2025 estimated the asteroid's diameter at approximately 60 ± 7 meters. Potential lunar impact effects could eject debris increasing the micrometeoroid flux in low Earth orbit by up to 1000 times for a few days, posing threats to astronauts and spacecraft. --- Mission Study and Options The paper explores space mission options for reconnaissance and mitigation if lunar impact is confirmed, covering: Mission Types Flyby and rendezvous reconnaissance missions to observe and characterize the asteroid. Deflection missions to alter the asteroid's trajectory. Robust disruption missions to break apart the asteroid. Launch and Propulsion Analysis Missions considered include rapid-response and delayed launches through the year 2032. Evaluation of chemical propulsion and solar electric propulsion. Assessment of various launch vehicles, deep space maneuvers, and gravity assists. Consideration of both re-tasking of existing spacecraft and deploying new spacecraft already built but not launched. Mission Feasibility Best reconnaissance missions would need to launch late 2028, leaving approx. 3 years for development as of August 2025. Deflection missions appear impractical given the timeline and conditions. Kinetic robust disruption missions are feasible with launches between April 2030 and April 2032. Nuclear robust disruption missions are feasible with launches between late 2029 and late 2031. Additional Utility Even if lunar impact is ruled out, deploying a reconnaissance mission has significant value for asteroid characterization and planetary defense preparedness. --- Implications The study highlights the challenges and complexities of responding to potential asteroid impacts within a short timeframe. The threat to both lunar environment and Earth's orbital assets due to possible ejecta from a lunar impact is significant. Investment in rapid mission development and robust disruption capabilities could be crucial for future planetary defense. --- Access to Paper View PDF HTML Version (Experimental) TeX Source --- Licensing The article is under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. --- Citation Barbee, B.W., Vavrina, M.A., Bull, R., Rudolph, A., Farnocchia, D., TerBeek, R., Atchison, J., Lyzhoft, J., Dotson, J., King, P., Chodas, P.W., Graninger, D., Mink, R.G., Kumamoto, K.M., Pearl, J.M., Burkey, M., Santistevan, I., Plesko, C.S., Caldwell, W.K., Harwell, M. (2025). Space Mission Options for Reconnaissance and