The asteroid (152830) Dinkinesh, a small S-type asteroid in the main asteroid belt, was studied by the Lucy spacecraft during a close fly-by. The spacecraft passed within 431 km of Dinkinesh, revealing its complex structure, including a longitudinal trough and an equatorial ridge. The discovery of a contact binary satellite, named (152830) Dinkinesh I. Selam, was a key finding. Selam consists of two nearly equal-sized lobes and orbits Dinkinesh at a distance of 3.1 km with a period of about 52.7 hours. The system is tidally locked, with Selam in synchronous rotation. The ridge and trough on Dinkinesh are likely the result of mass failure due to spin-up by the YORP effect, followed by reaccretion of shed material. The Lucy mission's encounter with Dinkinesh provided high-resolution images and photometric data, allowing the reconstruction of the shapes of Dinkinesh and Selam. Dinkinesh has an effective diameter of 719 m, while Selam's lobes have diameters of 210 m and 230 m. The system's shape model suggests that Dinkinesh has a volume-equivalent diameter of 719 ± 24 m. The system's angular momentum is dominated by Dinkinesh's spin and Selam's orbital motion, with a total angular momentum of 19.3 ± 4.4 × 10¹² kg m²/s. The system's bulk density is 2,400 ± 350 kg/m³, consistent with S-type asteroids. The study highlights the complexity of small asteroids in the main belt, suggesting that they may be more complex than previously thought. The Dinkinesh-Selam system provides insights into the formation of contact binary satellites and the role of the YORP effect in asteroid evolution. The findings contribute to our understanding of asteroid dynamics, including the formation of binary systems and the effects of tidal forces on asteroid rotation and structure.The asteroid (152830) Dinkinesh, a small S-type asteroid in the main asteroid belt, was studied by the Lucy spacecraft during a close fly-by. The spacecraft passed within 431 km of Dinkinesh, revealing its complex structure, including a longitudinal trough and an equatorial ridge. The discovery of a contact binary satellite, named (152830) Dinkinesh I. Selam, was a key finding. Selam consists of two nearly equal-sized lobes and orbits Dinkinesh at a distance of 3.1 km with a period of about 52.7 hours. The system is tidally locked, with Selam in synchronous rotation. The ridge and trough on Dinkinesh are likely the result of mass failure due to spin-up by the YORP effect, followed by reaccretion of shed material. The Lucy mission's encounter with Dinkinesh provided high-resolution images and photometric data, allowing the reconstruction of the shapes of Dinkinesh and Selam. Dinkinesh has an effective diameter of 719 m, while Selam's lobes have diameters of 210 m and 230 m. The system's shape model suggests that Dinkinesh has a volume-equivalent diameter of 719 ± 24 m. The system's angular momentum is dominated by Dinkinesh's spin and Selam's orbital motion, with a total angular momentum of 19.3 ± 4.4 × 10¹² kg m²/s. The system's bulk density is 2,400 ± 350 kg/m³, consistent with S-type asteroids. The study highlights the complexity of small asteroids in the main belt, suggesting that they may be more complex than previously thought. The Dinkinesh-Selam system provides insights into the formation of contact binary satellites and the role of the YORP effect in asteroid evolution. The findings contribute to our understanding of asteroid dynamics, including the formation of binary systems and the effects of tidal forces on asteroid rotation and structure.