This "plug-in" is not simple, the "housekeeper" of the extravehicular power distribution is very capable

On September 30, the Wentian Experimental Module was successfully transferred to the side berthing port of the Tianhe core module, and the main structure of the Chinese space station was transformed from a "I" shape to an "L" shape. During this mission, the Wentian Experimental Module, which was developed by the Fifth Academy of China Aerospace Science and Technology Corporation, was in good condition and its power supply and distribution were stable, which effectively ensured the successful completion of the transfer mission.

The Wentian Experimental Module is an all-rounder that combines platform functions with test payload functions. Its extravehicular exposure experimental platform is equipped with multiple standard payload interfaces for conducting extravehicular scientific experiments. Since there are many payload devices and they are arranged outside the cabin, if the power distribution unit is placed inside the cabin, it will bring a series of problems such as difficulty in laying high-voltage cables through the cabin and large transmission losses over long distances. This requires an extravehicular power distribution "steward" to "carefully" manage the power supply of these payload devices.

The "housekeeper" of the extravehicular power distribution of the Wentian Experimental Module

When the Wentian Experimental Module was successfully launched into orbit on July 24, 2022, a white square box on the module appeared in the image outside the module, which was particularly eye-catching against the blue background of the earth. This white box is the first stand-alone product of extravehicular power distribution in my country developed by the 529 Factory of the Fifth Academy, and it is also the "housekeeper" of the extravehicular power distribution of the Wentian Experimental Module.

This "housekeeper" is a cube of about 40 cm square, like a square suitcase with a handle. Although it is small in size, it is very capable. It provides dozens of power distribution channels of different power levels and is the single-machine product with the largest number of power distribution channels in the entire space station system. At the same time, it uses the solid-state power distribution switch technology independently developed by the 529th Factory of the Fifth Academy, which can not only supply power to the experimental payload equipment, but also automatically cut off the power supply in case of a fault, and restore the power supply after the fault is eliminated, realizing "intelligent power distribution" and providing stable and reliable power supply for the extravehicular experimental payload equipment.

Tolerant to space environment, convenient for astronauts to operate

Compared with in-cabin products, extravehicular electronic stand-alone products have more stringent requirements in terms of space environment design and ergonomic design, which brings new challenges to the research and development team in new environments, new conditions, new processes, etc.

Since the space station will frequently experience the sunlit and shadowed areas, the extravehicular products have to withstand the impact of temperature changes exceeding 200°C, space charged particle radiation, and the erosion of the atomic oxygen environment. These harsh environmental conditions have a significant impact on extravehicular power distribution products. To this end, the designers designed a set of heating devices inside the product to effectively prevent the electronic products from "losing temperature" due to the extremely low ambient temperature outside the cabin in the shadowed area; at the same time, active and passive thermal control measures are used to strengthen heat dissipation to ensure that the internal components will not malfunction due to excessive temperature in the sunlit area; protective measures are also taken to withstand space radiation and atomic oxygen environments.

Due to the complex layout of the space station's extravehicular equipment, it is much more difficult for astronauts to carry out extravehicular product maintenance in their space suits than to carry out maintenance inside the cabin. In order to facilitate the astronauts' operation, the designers cleverly designed a special anti-drift locking device to ensure that the extravehicular power distribution stand-alone products can be fixed to the cabin board without screws, preventing the stand-alone products from floating out of control during the disassembly and assembly process.

At present, the research and development of all power distribution and grid-connected control products (more than 100 sets) of large modules such as the Tianhe core module and the Wentian laboratory module of the space station are completed by the 529 Factory of the Fifth Academy. It plays a key role in ensuring the stable operation of the space station in orbit and is the veritable "steward" of the space station's energy system.

This year, China's space station will complete its in-orbit construction. The research and development team of the Fifth Academy will, as always, overcome difficulties and provide escort for the in-orbit operation of China's space station!