NASA’s DART Spacecraft Launches to Try to Redirect Asteroid

Category: Cover Story

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Several PSI scientists are working on the world’s first full-scale mission to test technology for defending Earth against potential asteroid or comet hazards. NASA’s Double Asteroid Redirection Test (DART) mission will impact a known asteroid that is not a threat to Earth. Jian-Yang Li, Eric Palmer, Stephen Schwartz, Amanda Sickafoose and Jordan Steckloff will be working on DART, which will attempt to slightly change an asteroid’s motion in a way that can be accurately measured using ground-based telescopes.

DART last week began its one-way trip to the Didymos asteroid system, which comprises a pair of asteroids. DART’s target is the moonlet, Dimorphos, which is approximately 530 feet (160 meters) in diameter. The moonlet orbits Didymos, which is approximately 2,560 feet (780 meters) in diameter. Since Dimorphos orbits Didymos at much a slower relative speed than the pair orbits the Sun, the result of DART’s kinetic impact within the binary system can be measured much more easily than a change in the orbit of a single asteroid around the Sun.

The spacecraft, about the size of a golf cart and weighing 1,210 pounds, or 550 kilograms, at impact, will intercept the Didymos system between Sept. 26 and Oct. 1, 2022, intentionally slamming into Dimorphos at roughly 4 miles per second (6 kilometers per second). Scientists estimate the kinetic impact will shorten Dimorphos’ orbit around Didymos by several minutes. Researchers will precisely measure that change using telescopes on Earth. Their results will validate and improve scientific computer models critical to predicting the effectiveness of the kinetic impact as a reliable method for asteroid deflection.