Carbon fiber composites are best known for their aerospace applications, appearing in aircraft, spacecraft, and satellites. China's satellite industry has navigated a challenging path to its current achievements. Here are some lesser-known historical milestones of carbon fiber in China's satellite programs.
Dongfanghong Satellites: A Nostalgic Legacy
The Dongfanghong satellites hold a special place in the memories of many, particularly those born in the 1970s and 1980s. Launched on April 24, 1970, the Dongfanghong-1 satellite remains operational today. However, it did not incorporate carbon fiber composites, as China's carbon fiber industry only began developing after 1965.
By the time Dongfanghong-2 launched in 1984, carbon fiber composites were used in its horn antenna support cylinder and despin mechanism. Subsequent Dongfanghong satellites increasingly adopted the material, leveraging its lightweight and high-strength properties to reduce satellite mass, lower launch costs, and ease technical challenges.
Four Key Applications of Carbon Fiber in China's Satellites
1. Carbon Fiber Corrugated Shells
- Dimensions: 920mm diameter, 235mm height.
- Structure: Composed of four trapezoidal corrugated panels bonded to upper/lower frames. Each panel features 33 corrugations made from high-modulus carbon fiber epoxy prepreg with ±45°, 0°, and ±45° layups.
- Performance: Compared to foreign counterparts (e.g., Company E's designs), axial compressive critical stress increased by 19% and elastic modulus by 26%. Outperformed domestic TA3 titanium alloy shells by 90% in load-bearing capacity at equal mass.
2. Dual-Peak Corrugated Load-Bearing Cylinders
- Weight: 25kg (largest carbon fiber primary load-bearing structure in early Chinese satellites).
- Design: 1983mm height, combining 48 dual-curve corrugations into a closed cylindrical structure. Upper section: 1088mm inner diameter; lower section: tapered with 1166mm inner diameter. External reinforcements include frames, ribs, and supports.
- Innovation: Variable-thickness thin-walled structure (0.32mm to 5.5mm) using high-modulus carbon fiber. Achieved single-cure, three-dimensional integrated molding of over 400 components.
- Outcome: Successfully launched in 1994 and 1997, proving 65% lighter than aluminum counterparts with superior structural efficiency.
3. Carbon Fiber-Aluminum Hybrid Skins
- Design: High-modulus carbon fiber skins, longitudinal hat-shaped stringers, and specialty frames paired with aluminum alloy end frames and joints.
- Applications: Developed 1300mm and 1620mm height stiffened shells (1187.6mm inner diameter), validated through rigorous testing and deployed on satellites.
4. Carbon Fiber-Honeycomb Sandwich Panels
- Advantages: Lightweight, high bending stiffness, airtightness, thermal insulation, and reduced assembly complexity.
- Usage:
- Dongfanghong-2: Solar array cylindrical shells and parabolic reflectors.
- Dongfanghong-3: Six 1720mm×2220mm carbon fiber grid-honeycomb solar array panels, dual-grid parabolic antenna reflectors, and 20+ honeycomb panels for structural systems.
- Resource Satellites: Expanded adoption, significantly reducing structural mass and freeing payload capacity.
From Aspiration to Reality
The Dongfanghong series embodies China's quest to explore space and secure communication sovereignty-a testament to generations of researchers' dedication. Today, with the BeiDou satellite network safeguarding national connectivity, carbon fiber composites have expanded beyond satellites to broader aerospace applications. As China sets its sights on the cosmos, carbon fiber remains an indispensable ally in reaching the stars.
