"Hard and Soft" to Protect Shenzhou - A Review of the Technological "Hard Support" of the Shenzhou 13 Manned Spacecraft on its Way Back

Recently, the return capsule of the Shenzhou 13 manned spacecraft landed safely in the designated area of ​​the Dongfeng landing site, and the Shenzhou 13 manned flight mission was a complete success. During this mission, a number of technical products independently developed and produced by my country provided full-process guarantee services for the smooth return of the Shenzhou 13 manned spacecraft.

On April 16, 2022, the return capsule of the Shenzhou XIII manned spacecraft successfully landed at the Dongfeng landing site. Photo by Xinhua News Agency reporter Lian Zhen

Radar "ruler" to protect flight

During the Shenzhou XIII manned flight mission, two measurement radars from the 23rd Institute of the China Aerospace Science and Industry Corporation II provided support throughout the entire process, starting tracking and measuring from the moment the return capsule of the Shenzhou XIII manned spacecraft entered the atmosphere. They acted like a "ruler" to measure real-time and accurate data and provide it to the control center, as well as provide effective target landing point data for the search and rescue operations ahead, escorting the return capsule to land safely.

It is reported that these two radars are mainly used to complete the tracking and measurement tasks of the return capsule. The core task of one measurement radar is to undertake the tracking and measurement of the return capsule inside and outside the black barrier area, and the core task of the other measurement radar is to track and measure the return capsule from parachute opening to landing.

When the return capsule enters the atmosphere, it rubs violently with the air around it, forming a high-temperature and high-pressure ionized gas layer. This gas layer wraps around the surface of the returner like a scabbard, isolating the communication between the return capsule and the ground measurement and control station, forming a black barrier area.

In order to solve the tracking and measurement problem in the black barrier area, the 23rd Institute independently developed a phased array measurement radar. Before the recovery mission, the support team carefully analyzed the guidance data to escort the return capsule on its way home.

The other radar is the tracking and measuring radar at the end of the recovery mission. It starts measuring the target after the return capsule opens its parachute. The radar uses a passive positioning system to achieve high-precision positioning of the return capsule from the time the parachute opens to the landing stage, providing timely and accurate data information for landing point prediction and return capsule search and rescue, and standing guard at the end of the recovery mission.

During this flight mission, a series of high-quality crystal components developed by the 203 Institute of the China Aerospace Science and Industry Corporation of China utilized the piezoelectric effect and frequency characteristics of stable quartz crystals to maintain stable beating in the harsh environment of space and generate accurate and stable frequency signals. They became an important reference indicator for ground commanders to monitor and measure flight status, and played an important role in ensuring the safe return of astronauts to Earth.

In addition, the rendezvous and docking microwave radar developed by the 25th Institute of the Second Academy of China Aerospace Science and Industry Corporation was also turned on again in this mission, accurately outputting the position information such as the relative distance, speed and angle between the Shenzhou 13 manned spacecraft and the core module of the space station, ensuring the smooth return of the Shenzhou 13 manned spacecraft; the environmental control and life-saving urine treatment subsystem developed by the 206th Institute of the Second Academy of China Aerospace Science and Industry Corporation, as an important link in the recycling of water resources in the space station, is one of the landmark key products for the space station mission to realize the long-term in-orbit residence of astronauts. Since it was launched into orbit on April 19, 2021, it has been operating stably in orbit, and all indicators of the distilled water produced meet the use requirements.

The Shenzhou 13 astronaut crew conducted a manual remote-controlled rendezvous and docking test of the Tianzhou 2 cargo spacecraft and the space station complex on January 8, 2022 at the Beijing Aerospace Flight Control Center. The Tianzhou 2 cargo spacecraft and the space station complex completed the forward rendezvous and docking accurately. Xinhua News Agency reporter Guo Zhongzheng

Smart "brake" to ensure accuracy

In the last few meters of the landing of the return capsule of the Shenzhou 13 manned spacecraft, the "Gamma Brake Commander" at the bottom of the return capsule was calmly measuring the speed and height of the return capsule from the ground. When the return capsule landed to the predetermined height, the reverse thrust engine ignition command was accurately issued, so that the return capsule landed smoothly under the action of reverse thrust, ensuring the astronauts' safe and comfortable return home.

The "Gamma Brake Commander" developed by the 35th Institute of the Third Academy of China Aerospace Science and Industry Corporation is a key device for the return capsule. The gamma ray detection system gives it the ability to penetrate surface vegetation and accurately measure the height of the bottom of the return capsule from the surface with an accuracy of centimeters. By emitting gamma rays to the surface and quickly capturing the reflected rays, precise calculations are performed in the "brain" of the "Gamma Brake Commander", and the height and speed information are extracted in real time. The reverse thrust ignition command is issued at the best time, realizing the optimal ignition plan of "high ignition height at high speed and low ignition height at low speed", maximizing the buffering performance of the reverse thrust engine.

On April 16, 2022, the return capsule of the Shenzhou XIII manned spacecraft successfully landed in the designated area of ​​the Dongfeng landing site. Photo by Xinhua News Agency reporter Lian Zhen

Sewing every stitch carefully

The main parachute that escorts the return capsule of the Shenzhou 13 manned spacecraft has an area of ​​1,200 square meters and is made up of more than 1,900 pieces of canopy. When fully unfolded, it can cover the size of three basketball courts. When straightened, it is nearly 70 meters long and can span a football field. It was developed by the 508th Institute of the China Academy of Space Technology.

The processing of such a parachute is a key step in the development of manned spacecraft, and is completed by a group of young and wise "female craftsmen". Fu Chunhui, a parachute product processor for the Shenzhou 13 manned spacecraft at the 508th Institute of the Fifth Academy of Aerospace Science and Technology, is one of them. She has undertaken many technical jobs with difficult sewing techniques and has become a technical backbone of parachute processing. "Sewing every stitch carefully" is her requirement for herself.

The processing requirements for the return capsule parachute of the Shenzhou XIII manned spacecraft are extremely high, and how to ensure that all dimensions of the 1,200 square meters of the main parachute are consistent in a limited space is the key. To this end, the research and development team repeatedly studied, found problems, and summarized experience... In the end, the tightness of the stitches of the 96 radial belts after processing was guaranteed to be consistent, ensuring that each one was of the same length.

Reporter: Hu Zhe, Song Chen

Source: Xinhua News Agency