NASA’s asteroid defence mission slowed targets by 1.7 inches per hour
Summary
NASA's recent analysis of its 2022 planetary defense test reveals that the mission successfully slowed down target asteroids, albeit by a minuscule amount. This groundbreaking work highlights the crucial role of volunteers in advancing planetary defense efforts.
Key Insights
Why was the slowdown of only 1.7 inches per hour considered successful despite being so small?
The tiny change in orbital speed—equivalent to 1.7 inches per hour—demonstrated that kinetic impact can alter an asteroid's trajectory, and over time, even small deflections can grow significantly enough to deflect a threatening asteroid away from Earth.
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How did scientists measure such a precise slowdown in the asteroids' orbit?
Researchers used observations from volunteer astronomers who recorded 22 stellar occultations—events where the asteroids passed in front of stars—between October 2022 and March 2025, allowing precise timing comparisons to reveal the orbital change.
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[1]