Achievement of the Planetary Defense Investigations of the Double Asteroid Redirection Test (DART) Mission
Authors: Chabot Nancy L. , Rivkin Andrew S. , Cheng Andrew F. , Barnouin Olivier S. , Fahnestock Eugene G. , Richardson Derek C. , Stickle Angela M. , Thomas Cristina A. , Ernst Carolyn M. , Terik Daly R. , Dotto Elisabetta , Zinzi Angelo , Chesley Steven R. , Moskovitz Nicholas A. , Barbee Brent W. , Abell Paul , Agrusa Harrison F. , Bannister Michele T. , Beccarelli Joel , Bekker Dmitriy L. , Bruck Syal Megan , Buratti Bonnie J. , Busch Michael W. , Campo Bagatin Adriano , Chatelain Joseph P. , Chocron Sidney , Collins Gareth S. , Conversi Luca , Davison Thomas M. , DeCoster Mallory E. , Prasanna Deshapriya J. D. , Eggl Siegfried , Espiritu Raymond C. , Farnham Tony L. , Ferrais Marin , Ferrari Fabio , Föhring Dora , Fuentes-Muñoz Oscar , Gai Igor , Giordano Carmine , Glenar David A. , Gomez Edward , Graninger Dawn M. , Green Simon F. , Greenstreet Sarah , Hasselmann Pedro H. , Herreros Isabel , Hirabayashi Masatoshi , Husárik Marek , Ieva Simone , Ivanovski Stavro L. , Jackson Samuel L. , Jehin Emmanuel , Jutzi Martin , Karatekin Ozgur , Knight Matthew M. , Kolokolova Ludmilla , Kumamoto Kathryn M. , Küppers Michael , La Forgia Fiorangela , Lazzarin Monica , Li Jian-Yang , Lister Tim A. , Lolachi Ramin , Lucas Michael P. , Lucchetti Alice , Luther Robert , Makadia Rahil , Mazzotta Epifani Elena , McMahon Jay , Merisio Gianmario , Merrill Colby C. , Meyer Alex J. , Michel Patrick , Micheli Marco , Migliorini Alessandra , Minker Kate , Modenini Dario , Moreno Fernando , Murdoch Naomi , Murphy Brian , Naidu Shantanu P. , Nair Hari , Nakano Ryota , Opitom Cyrielle , Ormö Jens , Michael Owen J. , Pajola Maurizio , Palmer Eric E. , Palumbo Pasquale , Panicucci Paolo , Parro Laura M. , Pearl Jason M. , Penttilä Antti , Perna Davide , Petrescu Elisabeta , Pravec Petr , Raducan Sabina D. , Ramesh K. T. , Ridden-Harper Ryan , Rizos Juan L. , Rossi Alessandro , Roth Nathan X. , Rożek Agata , Rozitis Benjamin , Ryan Eileen V. , Ryan William H. , Sánchez Paul , Santana-Ros Toni , Scheeres Daniel J. , Scheirich Peter , Berk Senel Cem , Snodgrass Colin , Soldini Stefania , Souami Damya , Statler Thomas S. , Street Rachel , Stubbs Timothy J. , Sunshine Jessica M. , Tan Nicole J. , Tancredi Gonzalo , Tinsman Calley L. , Tortora Paolo , Tusberti Filippo , Walker James D. , Waller C. Dany , Wünnemann Kai , Zannoni Marco , Zhang Yun 
Published: February 2024

NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos near-Earth asteroid binary system, demonstrating an autonomously navigated kinetic impact into an asteroid with limited prior knowledge for planetary defense. Months of subsequent Earth-based observations showed that the binary orbital period was changed by –33.24 minutes, with two independent analysis methods each reporting a 1σ uncertainty of 1.4 s. Dynamical models determined that the momentum enhancement factor, β, resulting from DART's kinetic impact test is between 2.4 and 4.9, depending on the mass of Dimorphos, which remains the largest source of uncertainty. Over five dozen telescopes across the globe and in space, along with the Light Italian CubeSat for Imaging of Asteroids, have contributed to DART's investigations. These combined investigations have addressed topics related to the ejecta, dynamics, impact event, and properties of both asteroids in the binary system. A year following DART's successful impact into Dimorphos, the mission has achieved its planetary defense requirements, although work to further understand DART's kinetic impact test and the Didymos system will continue. In particular, ESA's Hera mission is planned to perform extensive measurements in 2027 during its rendezvous with the Didymos–Dimorphos system, building on DART to advance our knowledge and continue the ongoing international collaboration for planetary defense.