Ultra-large space facilities such as space solar power stations, ultra-large-aperture antennas, and on-orbit servicing platforms have become priorities in aerospace development, Constrained by rocket fairing dimensions and stringent launch overload conditions, the traditional mode of"ground fabrication + rocket launch" cannot support the construction of structures ranging from hundreds of meters to kilometers in scale.

On-orbit construction, which eliminates the need for folded launches and circumvents payload size restrictions, enables direct in-space fabrication, joining, and integration of components. It has emerged as a core technology for next-generation aerospace systems.

Schematic Diagram of On-Orbit Construction of Large-Scale Space Antennas (Image by SIA)

Recently, a research team from Shenyang Institute of Automation (SIA) of the Chinese Academy of Sciences, together with collaborators, have developed an integrated technique that combines pultrusion of carbon fiber/polyetheretherketone (CF/PEEK) composite tubular units with laser transmission welding, offering a lightweight, high-strength, and high-reliability solution for the automated on-orbit assembly of large space truss structures.

The results were recently published in the prestigious international journal Space: Science & Technology, titled Manufacturing and Joining of Composite Units for On-Orbit Construction of Large Structures in Space, LI Yuxin, a postdoctoral researcher at SIA, as the first author, with Professor LUO Haitao serving as the corresponding author.

Prototype for Continuous Pultrusion Forming of Carbon Fiber Polyether Ether Ketone (CF/PEEK) Unit Pipe Fittings (Image by SIA)

Targeting two fundamental bottlenecks in on-orbit construction—efficient fabrication of high-performance structural units and reliable joining of components—the SIA CAS team proposed an innovative technical route.

Using CF/PEEK thermoplastic prepreg tape, they produced hollow tubular components through a continuous pultrusion process. The researchers systematically investigated the effects of temperature and pultrusion speed on mechanical properties and determined the optimal process parameters. The resulting composite tubes combine high specific strength, high stiffness, and excellent environmental adaptability, making them highly suitable for long-term service in space.

Ground demonstration and verification of on-orbit manufacturing for space structures

(truss products on the left, mirror frame products on the right)

(Image by SIA)

For the joining technology, the team innovatively adopted 3D-printed highly transparent PEEK connectors combined with laser transmission welding to achieve high-precision, high-strength integrated joining between tubes and connectors. This non-contact method features uniform stress distribution and high efficiency, effectively overcoming the drawbacks of traditional adhesive bonding, which is prone to aging, and mechanical fastening, which adds weight and offers insufficient reliability. The weld seams stably meet the load-bearing requirements of space structures.

To validate the engineering practicability of this approach, the team carried out the integrated manufacturing of a scaled-down prototype of a parabolic antenna truss based on theproposed method. They successfully demonstrated the entire process flow, from material forming and joining to structural assembly, proving that the proposed solution is well suited for automated on-orbit construction in space.

The Space Structure Dynamics and Optimization Design Team at SIA’s Center for Space Automation Technologies & Systems has long been dedicated to research on on-orbit construction of large space structures and composite material applications, continuously advancing the cross-integration of advanced manufacturing technologies and aerospace engineering.