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NASA’s DART Test Measurably Shifted an Asteroid System’s Solar Orbit, Studies Find

Peer‑reviewed analyses detail an ejecta‑boosted, precisely measured deflection with direct relevance for planetary defense.

Overview

  • A Science Advances study reports the DidymosDimorphos system’s roughly 770‑day solar orbit shortened by 0.15 seconds, a change equivalent to about 11.7 micrometers per second in velocity (approximately 4.3 cm per hour).
  • Researchers calculate an impulse‑amplification factor of about two, concluding that momentum carried away by impact ejecta doubled the effective push from the DART collision.
  • The heliocentric shift was constrained using 22 stellar occultations observed worldwide between October 2022 and March 2025, relying on precise timing contributed by volunteer astronomers.
  • Independent work reprocessing DART images, supported by laboratory experiments and numerical simulations, identifies fanned surface deposits on Dimorphos consistent with slow material transfer from Didymos driven by YORP‑induced shedding.
  • ESA’s Hera mission is scheduled to arrive in late 2026 to conduct in‑situ investigations that will refine measurements of the impact’s effects and the system’s surface evolution.