Red Star News:

China's space station has a designed lifespan of 10 years. Ensuring the long lifespan of spaceflight products and their high reliability is a rigorous test for every system and even every component. The core module assembly of the space station has been in orbit for nearly a year. What is its current status? Has it reached its goal as expected? Among multiple eye-catching parts in the phase of verifying key technologies of the space station, the robot arm is the focus and the highlight. How do you evaluate its performance? Thank you.

Hao Chun:

The questions are of much concern to all of us. We'd like Mr. Yang Hong, the chief designer of the space station, to answer them. 

Yang Hong:

Thank you for your questions. After the successful return of the Shenzhou-13 manned spacecraft, the assembly of the Tianhe core module and Tianzhou-3 cargo spacecraft are currently in orbit and in normal operation, with stable in-orbit operation parameters.

The core module has been in orbit for nearly a year, and all missions have been carried out smoothly as planned. We completed the rendezvous and docking with two manned spacecraft and two cargo spacecraft, as well as the three-month in-orbit stay of the Shenzhou-12 crew and the six-month stay of the Shenzhou-13 crew. We also carried out a number of special missions, including extravehicular activities, the test using the robotic arm to reposition cargo spacecraft, and manual remote operations.

During this period, we carried out a number of key technology verifications, mainly including physical and chemical regenerative life support, control of large complex, and large flexible solar panel wings and driving technologies. The evaluation results are in line with expectations, and the current functional performance is better than in the designs. Here are some examples: during the in-orbit stay of the Shenzhou-12 and Shenzhou-13 crews, the regenerative life support system of the Tianhe core module provided a good environment for astronauts to meet their material metabolism needs in orbit. The system collects the moisture discharged by the astronauts into condensed water and recycles and reprocesses urine into drinking water and electrolytic oxygen, making the water recycling efficiency higher than 95%, and the water utilization efficiency more than 83%, both meeting the requirements of the index. This technology greatly reduces astronauts' need for drinking water and oxygen to be carried by cargo spacecraft. As for the large flexible solar panel wings and their power supply technology, since the launch of the core module last year, they have been supplying power for the core module and its complex. The evaluation shows that their power generation capacity has reached around 10 kilowatts – far beyond the expected design. They have provided adequate power supply for power-consuming missions, including extravehicular activities, rendezvous and docking, and the test using the robotic arm to reposition cargo spacecraft. 

Currently, we have successfully completed four extravehicular activities, covering the operations, installation, and maintenance of extravehicular electronics, machines, pipelines and other typical equipment. This proves that the whole spacewalk procedures and support systems, as well as space-ground collaboration meet the requirements, laying a solid foundation for astronauts to take care of, install and maintain the extravehicular facilities during the follow-up long-term operation period after the completion of the space station. At present, we are carrying out a capacity assessment to further tap the potential of the core module and make full and best use of it.

The robot arm played an important role during the whole key technology verification phase. It completed a number of key tasks, such as astronauts' extravehicular activities, transfer of cargo spacecraft, and extravehicular status inspection, with perfect performance throughout the whole process. Extravehicular operations by the robot arm prove its joint motion ability, terminal positioning accuracy and other functions meet design expectations. Its stiffness in operating loads indicates it is able to transfer large loads. We also obtained the kinematic model parameters of the robot arm while weightless in orbit. All of these have laid a solid foundation for future missions, such as using the robot arm to grab and transfer the lab modules and taking care of large extravehicular loads. In a word, we have completed the mission of the key technology verification phase for the core module of the space station and achieved expected goals. Thank you.