Meeting Information

The First Planetary Defense Test Mission

January 18, 2023
Virtual

Date: January 18, 2023
Title: The First Planetary Defense Test Mission
Speaker: Andrew Cheng, Johns Hopkins Applied Physics Lab and Lead Investigator for the DART mission
Time: 1:00 p.m. Eastern Time (US and Canada); Zoom session starts at 12:00 p.m.

Abstract: On September 26, 2022 the Double Asteroid Redirection Test (DART) mission impacted the asteroid Dimorphos, the moon of the binary asteroid system Didymos, to demonstrate changing the orbit of an asteroid by a kinetic impact. If one day an asteroid is discovered heading toward the Earth, a kinetic impact may be used to prevent the asteroid from colliding with Earth. The DART impact on Dimorphos changed its orbit period around Didymos by 33+/-1 minutes. This was the first time the orbit of a planetary body has been measurably altered by mankind. The DART impact produced massive streams of ejecta that extended tens of thousands of km from the asteroid, producing a comet-like dust tail. The momentum transfer to Dimorphos from the DART impact was 3.61+/-0.2 times greater than the momentum carried by the DART spacecraft, assuming equal densities of Dimorphos and Didymos. These results validated the high effectiveness of kinetic impact for asteroid deflection.

Biography: Andrew Cheng is a planetary scientist at the Johns Hopkins Applied Physics Lab and Lead Investigator for the DART mission. He received his AB in physics from Princeton University in 1971, and his PhD in physics from Columbia University in 1977. He was previously Deputy Chief Scientist at NASA HQ. He was Project Scientist for the Near Earth Asteroid Rendezvous mission, the first to orbit and land on an asteroid. He was Principal Investigator of the LORRI camera on the New Horizons mission to Pluto.

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