又有好消息了！ 据国家航天局介绍截至1月3日6时天问一号探测器已经在轨飞行163天飞行里程突破4亿公里距离地球约1.3亿公里距离火星830万公里。 探测器姿态稳定，按计划将在一个多月后实施近火制动，进入环火轨道，准备着陆火星。 地球距离火星近点约为5500万公里，最远点则超过4亿公里。 据航天科技集团五院、天问一号探测器副总指挥李振才介绍，天问一号探测器目前每秒钟飞23千米，一天算下来基本上就是200万公里。 相对地球现在是21千米（每秒）左右，每天算下来应该是180万公里。相对于火星现在每天是以20万公里的里程奔向火星。 当天问一号探测器抵达火星附近时，将距离地球约1.9亿公里，总飞行里程将达到4.7亿公里。 The probe of China's first Mars mission Tianwen-1 had traveled more than 400 million kilometers by Sunday morning and is expected to enter Mars orbit next month, according to the China National Space Administration (CNSA). The probe is in stable condition at a distance of around 130 million kilometers from Earth and 8.3 million kilometers from the red planet after 163 days of flight, said CNSA. The distance between Mars and Earth varies periodically, from about 50 million kilometers to over 400 million kilometers. The latter is almost 10,000 times the length of Earth's equator. The probe is traveling at a speed of 23 kilometers per second, covering about 2 million kilometers a day. It flies at a speed of 21 kilometers per second relative to Earth's velocity, which means it is moving roughly 1.8 million kilometers away from Earth while 200,000 kilometers towards Mars every day, according to Li Zhencai with China Academy of Space Technology, deputy commander of the Mars probe. When the probe approaches Mars, it would have flown 470 million kilometers and be 190 million kilometers away from Earth. 关键“刹车”有序准备中 在今年2月10日左右，天问一号将进行关键的“刹车”，也就是临近火星后减速，被火星捕获，成为一颗火星卫星。 不久前，嫦娥五号探测器在抵达月球后进行了一次“刹车”，完成了近月制动；而相对于探月任务，天问一号探测器的近火制动则要困难得多。机会仍旧只有一次，但是由于距离太远，通信时延超过了十分钟，因此地面不能做任何实时控制和干预。 李振才介绍，这一次，探测器将自己判断并自动执行开机，地面团队只能在近一个小时后根据遥测数据得知最终的“刹车”完成情况。 李振才还说，他们可能会实施第四次奔火过程的中途修正，目标是为了获得捕获点的相关轨道参数，为精准捕获做准备。 The Mars probe will perform a critical "braking" maneuver to slow down before being captured into orbit around Mars. The long distance makes it a highly challenging task, as the communication will delay for over 10 minutes, leading to no real-time control or intervention from the ground crew. Usually, the ground team gives instruction to start up the engine, said Li, while "this time, the probe will do that automatically, and the ground team will only know about the status from telemetry data nearly an hour later." A fourth orbital correction may be implemented in order to obtain relevant orbital parameters of the point where the probe will be captured, Li added. Tianwen-1 is China’s first independent interplanetary mission. 推荐阅读：九天云外揽月归！今天，为“嫦娥”转发 “天问”，问天！