An on-orbit demonstration of asteroid deflection is a key test that NASA and other agencies wish to perform before the actual need is present. The Double Asteroid Redirection Test (DART) mission is NASA's demonstration of kinetic impactor technology, impacting the asteroid to adjust its speed and path. DART will be the first ever space mission to demonstrate asteroid deflection by kinetic impactor.
Launch Window: opens July 22, 2021
DART Impact: September 27– October 2, 2022
DART's target is the binary asteroid system Didymos, which means "twin" in Greek (and explains the word "double" in the mission's name). Didymos is not on a path to collide with the Earth but rather represents an optimum candidate for humankind's first planetary defense experiment. The Didymos system is composed of two asteroids: the larger, 780-m-diameter asteroid Didymos A, and the smaller moonlet asteroid, 160-m-diameter Didymos B, which orbits the larger asteroid. The DART spacecraft will impact into Didymos B nearly head-on, shortening the time it takes the small asteroid moonlet to orbit Didymos A on the order of minutes.
Because Didymos is an eclipsing binary asteroid as viewed from the Earth, Earth-based telescopes will be able to measure the change in the orbit of Didymos B. The timing of the DART impact, in the Fall of 2022, is chosen to minimize the distance between Earth and Didymos to enable the highest quality telescopic observations. Didymos will still be roughly 11 million kilometers from Earth at the time of the DART impact, but telescopes across the world will be able to contribute to the global international observing campaign to determine the effect of DART's impact.
The DART demonstration has been carefully designed. The impulse DART delivers to the Didymos binary asteroid system is low and cannot disrupt the asteroid, and Didymos's orbit does not intersect Earth's at any point in current predictions. The DART test is a demonstration of capability to respond to a potential asteroid impact threat, should one ever be discovered.
The DART mission is being developed and led for NASA by the Johns Hopkins University Applied Physics Laboratory. NASA's Planetary Defense Coordination Office is the lead for planetary defense activities and is sponsoring the DART mission. Partner institutions on DART include: NASA Goddard Space Flight Center, NASA Johns Space Center, NASA Langley Research Center, NASA Glann Research Center, NASA Marshall Space Flight Center, Jet Propulsion Laboratory, Aerojet Rocketdyne, Lawrence Livermore National Laboratory, Auburn University, University of Colorado, University of Maryland, Northern Arizona University, Planetary Science Institute, and Agenzia Spaziale Italiana.
DART is related to a larger effort known as AIDA, Asteroid Impact and Deflection Assessment. AIDA represents the acknowledgement that planetary defense is an international effort, and that scientists and engineers around the world seek to solve problems related to planetary defense through international collaborations.
The Hera mission is currently a candidate ESA mission as part of the Agency's new Space Safety and Security program. Hera would launch in 2023 and arrive at the Didymos system in 2027, to conduct a six-month survey of both asteroids, with a particular focus on the crater left by DART's collision. The two missions, DART and Hera, are being designed and operated independently, but their combination will boost the overall return to a significant degree. NASA's DART mission is fully committed to international cooperation, and Hera team members are full members of the DART team, to contribute to DART's planetary defense investigations and to fully inform Hera's mission.