开启十年“追星”路 天问二号先“取星尘” 再探彗星

Core Viewpoint - The successful launch of the Tianwen-2 probe marks a significant advancement in China's deep space exploration, initiating the country's first dual-target exploration of extraterrestrial small bodies [1][4]. Group 1: Mission Objectives - The Tianwen-2 mission has two primary objectives: to conduct a flyby, sample collection, and return from the asteroid 2016 HO3, and to perform scientific exploration of the main belt comet 311P [4]. - The mission is designed to complete multiple tasks in a single launch, with a total mission duration of approximately 10 years, encompassing 13 flight phases [7]. Group 2: Mission Phases - The asteroid sampling and return process consists of nine stages, starting with the launch phase, followed by the asteroid transfer phase lasting about one year, which includes deep space maneuvers and mid-course corrections [9]. - After reaching the asteroid, the probe will enter various phases including approach, rendezvous, and close-range exploration, ultimately determining the sampling area before executing the sample collection [10]. Group 3: Scientific Significance - The asteroid 2016 HO3 is considered a "quasi-satellite" of Earth, providing valuable insights into the early solar system's material composition and evolutionary history [11]. - The main belt comet 311P, located between Mars and Jupiter, possesses characteristics of both comets and asteroids, making it crucial for understanding the composition and evolution of small celestial bodies [13]. Group 4: Challenges and Difficulties - The Tianwen-2 mission faces significant challenges, including the precise design of the trajectory to the asteroid, which requires high accuracy due to the differing orbital periods of the Earth and the asteroid [16]. - Sampling methods must be adaptable to varying surface conditions of the asteroid, necessitating careful planning post-close-range exploration [17]. - The return phase involves overcoming extreme conditions during re-entry, with speeds approaching 12 kilometers per second, requiring meticulous engineering of thermal protection and aerodynamic design [18].