今年5月29日，行星探测工程天问二号探测器成功发射，开启小行星探测与采样返回之旅。天问二号主 要任务目标是对小行星2016HO3进行探测、取样并返回地球，此后再对主带彗星311P开展科学探测，其 间共包含13个飞行阶段，计划最远到达距离地球约1.5亿至5亿公里处。 《 人民日报 》（ 2025年09月22日 13 版） (责编：杨光宇、胡永秋) 关注公众号：人民网财经 311P主带彗星是运行于火星与木星轨道之间小行星带中的小天体，同时具有传统彗星的物质构成特征 和小行星的轨道特征。对该主带彗星进行探测，能够大幅促进对小天体的物质组成、结构以及演化机制 等探索。 天问二号任务采用"边飞边探边决策"的实施策略。为有效应对小行星2016HO3特性的不确定性，同时尽 最大可能获取小行星样品，天问二号共设计了触碰、悬停、附着3种采样模式。天问二号探测器共搭载 了11台科学载荷，对目标天体的地形地貌、内部结构、物质组成，以及可能存在的喷发物等方面开展相 关的探测以及科学研究，为拓展人类对宇宙的认知提供科学支撑。 在完成小行星采样任务后，天问二号返回舱预计于2027年底着陆地球并完成回收；此后，主探测器将按 计划继续飞行， ...

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]

Core Viewpoint - The successful launch of the Tianwen-2 probe marks China's first mission to explore and sample an asteroid, advancing deep space exploration efforts [1][3]. Group 1: Mission Overview - The Tianwen-2 probe was launched on May 29, 2023, at 1:31 AM using the Long March 3B rocket, entering a transfer orbit to the asteroid 2016 HO3 after approximately 18 minutes of flight [3]. - The primary objectives of the Tianwen-2 mission include exploring the asteroid 2016 HO3, collecting samples, and returning them to Earth, with an expected landing date by the end of 2027 [3]. - Following the asteroid mission, the probe will conduct scientific exploration of the main belt comet 311P, which is located between the orbits of Mars and Jupiter [3]. Group 2: Technical Aspects of the Launch - The Long March 3B rocket, known as China's "gold medal rocket," has a high reliability rate and is primarily used for launching high-orbit spacecraft [4]. - This launch marks the 109th mission for the Long March 3B rocket, which has previously successfully launched various satellites, including the Chang'e lunar probes [6]. - The rocket's trajectory design and system optimizations were crucial for ensuring the success of the Tianwen-2 mission, with the launch team overcoming numerous challenges to achieve this high-density launch schedule [6][9]. Group 3: Precision and Challenges - The mission to the asteroid requires extremely high precision in orbital insertion, with a deviation limit of no more than 1 meter per second [7]. - The rocket's insertion speed needed to reach 11.2 kilometers per second, comparable to making a basketball shot from Shanghai to a hoop in Beijing, while ensuring the correct angle and speed upon entry [9]. - The design workload for this mission was three times greater than that of conventional launches, necessitating two years of iterative optimization by the rocket development team [9].

Core Points - China's Tianwen-2 probe successfully launched on May 29, marking the country's first asteroid exploration and sample return mission [1][2] - The mission aims to explore and collect samples from asteroid 2016 HO3, with a planned return to Earth by the end of 2027 [7][8] Group 1: Mission Overview - The Tianwen-2 mission is a significant engineering project, described as a relay race, with the successful launch being the first leg [4] - The probe is equipped with 11 scientific payloads to enhance understanding of small celestial bodies [8] - The mission has a total duration of approximately 10 years, including subsequent exploration of main belt comet 311P [7] Group 2: Technical Details - The Long March 3B rocket, known for its reliability, executed its 109th mission and was specifically designed for this escape trajectory [14][16] - The launch required high precision, with the entry trajectory needing to be accurate to within 1 meter per second [21] - The design and preparation for the mission involved three times the usual workload due to the complexities of deep space exploration [23] Group 3: Challenges and Innovations - The Tianwen-2 mission is characterized by its high difficulty, long duration, and significant risks [8] - The rocket team faced challenges in optimizing the launch process and ensuring timely execution of the mission [20][18] - Innovations in guidance methods were implemented to meet the demands of deep space trajectory requirements [21]

Group 1 - The core viewpoint of the article highlights China's successful launch of the Tianwen-2 probe, marking the country's first asteroid sampling and return mission, following the Tianwen-1 Mars exploration mission [1][3] - The Tianwen-2 mission aims to achieve multiple objectives, including the exploration and sampling of asteroid 2016HO3 and subsequent scientific investigation of main-belt comet 311P, with a focus on key technological breakthroughs and providing valuable data for research on asteroid origins and evolution [4][6] - The mission involves a complex flight process with 13 stages over approximately 10 years, including phases for approaching, detecting, and sampling the asteroid, followed by a return phase expected to conclude with landing on Earth by the end of 2027 [5][6] Group 2 - The Tianwen-2 mission presents new technical challenges compared to previous missions, as scientists face uncertainties regarding the rotation speed and surface conditions of asteroid 2016HO3, necessitating a "fly, explore, and decide" strategy [6][7] - The mission's complexity is further compounded by the weak gravitational conditions of the asteroid, which has an average diameter of about 41 meters, requiring the probe to achieve stable attachment and sampling under high-speed rotation and low gravity [6][7] - The long-distance nature of the mission, with asteroid 2016HO3 located between 18 million to 46 million kilometers from Earth and main-belt comet 311P between 150 million to 500 million kilometers away, imposes high demands on orbital design, energy management, and the probe's longevity and reliability [7]