China’s space station’s electric propulsion engine achieves first in-orbit gas exchange


China’s manned spaceflight Tiangong Space Station recently achieved a new first by successfully installing an electric propulsion system gas cylinder in-orbit through a robotic arm. It is believed to be beneficial to maintain the long-term orbit safe and stable flight of the space station, reported Chinese newspaper Global Times.

For the first time, the 801 research institute of China Aerospace Science and Technology Corporation (CASC) 6th Academy has adopted a “gas exchange” method instead of “gas replenishment” to supplement the electric propulsion propellant xenon gas, according to a statement the Global Times received from the institute on Tuesday.

The use of the electric propulsion system on the Tiangong Space Station marks its debut in manned spaceflight. With the addition of the gas bottle as an “external attachment,” the service life of the space station’s electric propulsion system will be significantly extended, playing a crucial role in the long-term safe and stable operation of the station.

The electric propulsion system, also known as the electric propulsion engine, firstly converts inert gases such as xenon into charged ions, then accelerates and ejects these ions to generate thrust, which will power tasks such as spacecraft attitude control, orbit correction, and maintenance.

The in-orbit instalment was completed through a simplified floating docking method: achieving the initial positioning of the robotic arm through a coarse positioning guiding device, followed by further correction through autonomous fine positioning. This approach can achieve the reliability of docking even after multiple in-orbit disassembly and reassembly operations.

Considering uncontrollable factors in the space environment, astronauts are also able to manually replace the gas bottle in addition to the robotic arm’s automatic in-orbit replacement.

In May, China launched the Shenzhou-16 manned spaceship, sending three taikonauts to its space station combination for a five-month mission.