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.

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双小行星重定向测试（DART）任务的行星防御调查的成果

NASA 的双小行星重定向测试 (DART) 任务是第一个演示小行星偏转的任务，该任务的 1 级要求指导了其行星防御调查。在此，我们总结了 DART 对这些要求的实现。 2022 年 9 月 26 日，DART 航天器撞击了 Dimorphos，Didymos 近地小行星双星系统的次要成员，展示了对行星防御先验知识有限的小行星的自主导航动力撞击。随后几个月的地球观测表明，双星轨道周期改变了 –33.24 分钟，两种独立的分析方法各自报告了 1σ不确定度为 1.4 秒。动力学模型确定了动量增强因子，β，DART 动力学冲击测试得出的结果介于 2.4 和 4.9 之间，具体取决于 Dimorphos 的质量，这仍然是最大的不确定性来源。全球和太空中的五打望远镜以及用于小行星成像的意大利轻型立方体卫星为 DART 的调查做出了贡献。这些综合研究解决了与双星系统中两颗小行星的喷射物、动力学、撞击事件和特性相关的主题。 DART 成功撞击 Dimorphos 一年后，该任务已达到其行星防御要求，不过进一步了解 DART 的动能撞击测试和 Didymos 系统的工作仍将继续。特别是，欧空局的赫拉任务计划在 2027 年与 Didymos-Dimorphos 系统会合期间进行广泛的测量，以 DART 为基础，以增进我们的知识并继续正在进行的行星防御国际合作。