天问二号踏上十年“追星之旅”，我国首次小行星探测与采样返回任务正式开启

Core Points - The successful launch of the Tianwen-2 probe marks China's first asteroid exploration and sample return mission, aiming to study asteroid 2016HO3 and comet 311P over a mission period of approximately 10 years [1][4] - The mission is expected to provide valuable data on the early state of the solar system and the evolution of both the solar system and Earth [1][4] Mission Objectives - The primary engineering goal is to gather data and samples from asteroid 2016HO3, focusing on its origin and evolution [4][5] - Scientific objectives include measuring various physical parameters of both asteroid 2016HO3 and comet 311P, such as orbital parameters, rotation, shape, size, and thermal radiation characteristics [4][5] Significance of Target - Asteroid 2016HO3 is considered a "time capsule" or "living fossil" of the solar system, having remained unchanged since its formation around 4.5 billion years ago, making it scientifically valuable [4][5] - The study of small asteroids like 2016HO3 is crucial for understanding Earth's evolution, particularly regarding the origins of water on Earth, which is believed to have been delivered by such celestial bodies [4][5] Mission Phases - The Tianwen-2 mission consists of 13 flight phases, including launch, asteroid transfer, close approach, sampling, and return to Earth, with the asteroid exploration phase expected to take about 2.5 years [7][9] - The mission will utilize a "fly while explore and decide" strategy, allowing the probe to autonomously make decisions as it approaches the target [10] Challenges - The mission faces significant challenges due to the unknown characteristics of asteroid 2016HO3, including its surface composition and structure, which complicates the sampling process [9][10] - The small size of the asteroid (40-100 meters in diameter) presents difficulties in sampling, requiring precise control of the probe in a microgravity environment [10]