Core Points - The Shenzhou 20 astronaut crew is expected to return to the Dongfeng landing site this afternoon, with an animated demonstration provided to illustrate their journey home [1] Group 1: Key Actions During Return - The Shenzhou 21 spacecraft performed docking maneuvers at 19 meters and 200 meters, completing a 180-degree turn before entering the final phase of its return [3] - The first critical action involved a 90-degree rotation of the spacecraft, followed by the separation of the orbital module and the return module, completed within approximately two minutes [3] - The "blackout zone" occurs when the return module separates from the propulsion module at about 145 kilometers altitude, leading to a loss of radio communication due to atmospheric re-entry [4] Group 2: Descent and Landing Procedures - The third critical action involves deploying parachutes at an altitude of 10 kilometers, utilizing a three-stage parachute system to reduce descent speed to 7-8 meters per second [5] - The final landing action includes firing four retro-thrust engines when the return module is about 1 meter above the ground, allowing for a landing speed of approximately 2 meters per second [7]

央视网消息：神舟十九号三名航天员4月30日就将返回地球。回家的这一路是如何经历重重难关的？通过增强现实技术一起了解神舟 十九号返回的全过程。 首先，神舟十九号撤离空间站节点舱前向端口，先后在19米、200米停泊点停泊。此后，神舟十九号飞船逐渐远离空间站，并完成 180度的掉头，变成正飞的姿态，也就是从推进舱在前变成轨道舱在前。 这次神舟十九号返回依然采取"快速返回方案"，绕飞地球的圈数从早先的11圈缩短到了5圈，用时7个半小时。大幅缩短了航天员返 程的时间，也减轻了航天员在狭小的返回舱内长时间停留的不适感。 经过5圈的准备和等待后，最后的冲刺阶段就开始了。在大约50分钟时间里，返回舱将从大约390公里的高度回到地面。这一路，返 回舱要穿越重重难关，这期间有四组关键动作。 第一组，两次调姿、轨返分离。这组动作在大约390公里的高度完成。先是一次调姿，飞船水平方向旋转90度。 轨返分离之后，紧接着就是飞船二次调姿，继续在水平方向旋转90度，变成推进舱在前，返回舱在后，也就是倒着飞，而且推进舱 还会翘起来，有一个俯仰角，为制动减速，进入返回轨道做准备。 一次调姿到位，马上就是轨返分离，也就是轨道舱和返回舱之间分离。 ...