CAS Space, a leading Chinese commercial space company, has completed a series of propulsion system tests for its Kinastra 1 upper stage, clearing the way for the vehicle's maiden flight in the first quarter of 2027.

The Guangzhou-headquartered company, established by the Chinese Academy of Sciences, said the upper stage's full propulsion system completed the PV-001 integrated compatibility hot-fire test in August, marking a major system-level milestone that verified coordination and operational reliability across all subsystems. The test lasted 566 seconds, with all units performing stably.

The Kinastra 1's 20-kilonewton engine passed a series of boundary condition tests in March, covering variable operating modes, mixture ratios and cooling percentages. The tests involved 18 ignitions and a total burn time of 481 seconds.

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A reliability test followed in July, during which the engine ran for a combined 2,906 seconds under multiple operating scenarios. According to CAS Space, the engine has now accumulated a total ignition time of 5,211 seconds.

The latest test comprehensively validated the engine's pressurization, propellant feed, propellant management and servo control systems, the company said. Engineers also verified three crucial capabilities: the 20-kN engine's high-thrust, high-performance multiple-restart capability; balanced propellant delivery from parallel tanks; and a highly reliable integrated electrical design.

The Kinastra 1 is equipped with a 20-kN-thrust engine capable of more than 20 ignitions. According to engineers, the upper stage can autonomously plan orbital transfer paths, withstand the vacuum and extreme temperature fluctuations of spaceflight, and adapt to various launch vehicles, making it a key component of CAS Space's medium-and high-orbit and deep-space launch capabilities.

The upper stage works like a "space shuttle bus". It does not launch from the ground but performs transfer operations in space. After a rocket delivers the upper stage and satellite payloads into space, the upper stage takes over the mission, transferring satellites between orbits. This approach saves satellites' fuel and allows multiple satellites to be deployed into different orbits during a single launch mission.

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Yang Haoliang, chief designer of the Kinastra 1, said the upper stage is an optional module for rockets. It operates after a rocket's core stage and strap-on boosters have exhausted their fuel and separated, propelling spacecraft onto interplanetary trajectories or into orbits higher than those that could otherwise be reached using conventional boosters.

An upper stage can extend a rocket's reach beyond the parking orbit where its core stages run out of fuel, delivering payloads to higher and more distant orbits through multiple in-space ignitions, Yang said. This helps conserve satellite propellant that would otherwise be used for orbit-raising, thereby extending satellites' operational lifespans.

"It also enables multi-satellite deployment across different altitudes and inclinations for rapid constellation buildup, shortens the time needed to adjust satellites' orbital positions, and can perform controlled de-orbiting at mission end to reduce space debris," Yang said.

Contact the writers at zhaolei@chinadaily.com.cn