“天问一号”探测器完成第二次轨道中途修正
2020年9月20日23时，在我国首次火星探测任务飞行控制团队控制下，“天问一号”探测器4台120N发动机同时点火工作20秒，顺利完成第二次轨道中途修正，并在轨验证了120N发动机的实际性能。
截至目前，“天问一号”已在轨飞行60天，距离地球约1900万千米，飞行路程约1.6亿公里，探测器各系统状态良好，地面测控通信各中心和台站跟踪正常。
中途修正一般是指在探测器飞行过程中，对各种原因导致的轨道偏离进行修正，使探测器更贴近理论轨道飞行。“天问一号”发射入轨和第一次中途修正的精度很高，本次修正量很小。
后续，探测器还将飞行5个月左右抵达火星附近，被火星引力捕获后进入环火轨道，开展着陆火星的准备和科学探测等工作。
China's Tianwen-1 probe, carrying out the country's first mission to Mars, smoothly conducted its second mid-course orbital correction on Sunday, according to the China National Space Administration (CNSA). The probe completed the orbital correction at 11 p.m. Beijing time, after four of its 120N engines worked for 20 seconds. The performance of the 120N engines was also tested during that time.
So far, the probe has been in orbit for 60 days and has traveled about 160 million kilometers, with all its systems in sound condition. It is currently about 19 million kilometers away from the Earth. Mid-course correction can be caused by various factors during the flight and is carried out to ensure the probe comes closer to the theoretical orbit.
Since Tianwen-1 made a highly accurate launch and first mid-course correction, the second correction was minor, according to the CNSA. Next, the probe is expected to perform a deep space maneuver in October. Compared with the orbit correction, the deep space maneuver is a larger orbital control action, which will adjust the inclination and size of the orbit.
Given the probe's current distance from Earth, one-way communication is delayed by about a minute. The probe will continue traveling away from Earth at a speed of about 300,000 kilometers per day, posing more challenges in communication. But the development team is prepared. The execution of the deep space maneuver has been planned in detail, including the content and sending time of each instruction. Contingency plans have also been made in case of possible abnormal situations.
China launched its first Mars mission Tianwen-1, which means "Questions to Heaven," on July 23, marking the country's first step in planetary exploration of the solar system. The probe carried out the first orbital correction on August 2.