A Falcon 9 upper stage launched in January 2025 was left in a high‑energy Earth‑Moon orbit after delivering two lunar landers. Over the next 16 months it drifted in a wide, 26‑day elliptical path that repeatedly crossed the Moon’s trajectory, eventually being predicted by independent tracker Bill Gray to strike the Moon near Einstein crater on 5 August 2026 at ~8,700 km/h. The impact will act as a natural excavator, exposing subsurface material and providing valuable data for lunar science, habitat design, debris safety, and impact‑model validation—while also highlighting the growing risk of uncontrolled space‑hardware disposal in cislunar space and the need for deliberate, solar‑orbit disposal strategies to protect future lunar operations.
1. Falcon 9 upper stage launched on January 15, 2025 from Kennedy Space Center launchpad 39A.
2. The stage carried Firefly Aerospace's Blue Ghost and Espac's Resilience lunar landers.
3. Blue Ghost landed on the moon in March 2025.
4. Resilience lost contact during its landing attempt and crashed on the lunar surface.
5. After releasing the landers, the Falcon 9 upper stage (designated 2025‑010D) was abandoned in deep Earth orbit.
6. The abandoned stage entered an elliptical Earth orbit with a period of about 26 days, perigee ≈ 220,000 km and apogee ≈ 510,000 km.
7. Its orbit repeatedly crosses the moon's orbital path.
8. The stage has drifted in the Earth‑Moon system for nearly 16 months.
9. Scientists predict it will impact the lunar surface near Einstein crater on August 5, 2026.
10. Predicted impact speed is about 8,700 km/h (≈ 2.44 km/s).
11. The impact will eject subsurface material, acting as a natural excavator.
12. Einstein crater is approximately 198 km in diameter.
13. Inside Einstein crater lies a younger, sharper crater named Einstein A.
14. The Falcon 9 upper stage has a mass of about 4 metric tons.
15. Bill Gray, an independent orbital dynamics specialist, predicted the impact using Project Pluto software.
16. Gray's prediction relied on over 1,000 optical observations from amateur astronomers, automated sky surveys, and professional observatories.
17. Radar tracking is ineffective at lunar distances; optical methods were used.
18. NASA plans to use the Lunar Reconnaissance Orbiter to image the impact site before and after the collision.
19. Data from the impact will help assess lunar surface response for future habitat and landing‑pad design.
20. Understanding debris spread from the impact can inform safe distances between lunar bases and operational zones.
21. The moon's weaker gravity and lack of atmosphere alter impact behavior compared to Earth.
22. The event provides a test case for high‑speed impact models used for meteorites and space‑debris hazard predictions.
23. Uncontrolled collisions of abandoned objects in cislunar space could contribute to a lunar Kessler syndrome scenario.
24. To mitigate long‑term hazard, experts recommend reserving extra fuel to send upper stages into heliocentric or solar orbits after mission completion.
25. The European Space Agency has implemented responsible disposal strategies and demonstrated a solar‑orbit disposal maneuver during the Marsbound Escapade mission in late 2025.
26. During the Apollo era and NASA's LCROSS mission in 2009, spacecraft were intentionally crashed into the moon for controlled scientific experiments.
27. The key distinction between those events and the Falcon 9 stage is that the earlier impacts were deliberately controlled.