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Advanced composite materials and advances in high-rate production of composite structures are reshaping the landscape of satellite design and manufacturing. Traditional satellite development has long relied on expensive materials and labor-intensive manufacturing processes like as hand layup, justifiable only for billion-dollar spacecraft. But the rapid expansion of the commercial satellite market — particularly in large constellations of small satellites — demands a paradigm shift: faster production, lower costs and high-performance materials suited for high-volume manufacturing.

To that end, three veteran composite suppliers have partnered to develop a lower-cost, reduced-labor approach for lightweight high modulus (HM) carbon fiber-reinforced polymer (CFRP) cored panels used in applications including satellite optical benches, solar array substrates, reflectors and modular building blocks for main structures. Using A&P Technology’s (Cincinnati, Ohio, U.S.) QISO braided material,  (PMT, Benicia, Calif., U.S.) produces Apex CFRP cellular core that is one-tenth the cost of HM honeycomb core while maintaining the lightweight and ultra-low coefficient of thermal expansion (CTE) necessary for high-precision optics and high-performance structures.

PMT is also using QISO to produce robust single-ply facesheets. These components are being combined by Rock West Composites (RWC, San Diego, Calif., U.S.) for its Strato line of sandwich panels, plates and tubes, and solar array substrates for space. The latter, as well as radio frequency (RF) communication reflectors, have been tested by RWC, demonstrating manufacturability and performance advantages key for the next generation of satellites, including the ability to significantly reduce design-to-production cycles and materials/structures qualification.

Space legacy suppliers partner for new approach

PMT has a long history of pioneering high-performance composites for aerospace, defense, industrial and space markets. The company is known for its deep expertise in resin systems, prepregs and core materials that meet demanding thermal and mechanical requirements. PMT president Nick Patz says the company recognized the need for a new approach — one that delivers high-performance materials at a fraction of the previous cost.

“Over the last 10 years, we’ve noticed a shift in the marketplace where large satellites are being replaced with constellations,” he says, “A lot of the materials we’ve developed are to replace those traditionally used in large satellites.”

Despite the need for high-rate production and lower costs, performance remains a key driver. Space applications require lightweight, HM materials with low CTE. Searching for solutions to meet the necessary performance criteria and also achieve manufacturability that supports the booming demand for small- and medium-sized satellites, PMT began collaborating with RWC and A&P Technology.

Known for its agility and engineering depth, RWC bridges the gap between R&D and scalable production. The company specializes in the design and manufacturing of composite structures for space, defense and commercial applications. RWC offers a line of space-grade products designed to provide access to high-quality components with shorter lead times. Its Strato line of products meet key requirements for space, including low outgassing, low-to-zero CTE, HM materials and a wide operational temperature range.

Meanwhile, A&P Technology, a long-time partner to the aerospace sector, is supplying advanced braided fabrics to the collaboration, including its 0°, +/-60° QISO material. QISO contributes multidirectional strength, drapability and improved manufacturing efficiency.

By leveraging spread tow technologies and advanced manufacturing techniques, the partners are creating lightweight, high-performance carbon fiber cores and prepreg systems specifically designed for small- and medium-sized satellites. “When you’re making hundreds or thousands of satellites, you want the same zero CTE, low outgassing, high stiffness and low density achieved with traditional large satellite constructions, but you need it at a lower price point,” Patz explains. “By combining our core technology with some tow spreading and A&P’s braiding technology, we’re bringing those same properties down into an economical realm, both in terms of materials costs as well total manufacturing cost.”

Single-ply skins, CFRP core

PMT has been working with A&P Technology over the last few years to develop HM prepregs for skin and core materials specifically designed for space applications. The in-plane isotropy of A&P’s +/- 0°, 60° QISO fabric enables single-ply layups that meet performance requirements while reducing ply count and fabrication complexity.

Skin materials for cored sandwich panels in most traditional space applications use HM carbon fiber-reinforced cyanate ester prepregs. Typically, large satellite customers combine eight-ply quasi-isotropic skins with a cellular core to make structural sandwich panels. PMT’s approach uses only one ply of Hexcel’s (Stamford, Conn., U.S.) HexTow HM63-based QISO for these skins in place of eight plies of HM unidirectional (UD) tape. The spread tow QISO thus decreases the fiber mass for each of the skins down from eight plies of 100 grams/square meter (gsm), or 800 gsm, to 310 gsm.

PMT uses this same approach to create its Apex vented CFRP core material. Satellite structures have traditionally used vented honeycomb cores to prevent damage to the structure from rapid pressurization during launch. For Apex cellular core, PMT controls the spread tow material to provide an open structure that enables venting through the cell walls without having to manually perforate them, as is required with aluminum or Nomex honeycomb cores. The spread tow QISO also cuts the amount of material needed by half yet still meets PMT’s strength and stiffness targets. With reduced material use and simpler layup, Apex core is one-tenth the cost of traditional HM core, notes Patz, and offers a structure with low moisture uptake and a boost in shear performance.

The amount of material saved translates into cost savings and decreased density. “It’s actually a pretty expensive material, which would keep it out of the realm of applicability to these commercial markets,” Patz explains, “but we’re using a lot less material, which reduces the cost per square foot of reinforcement, enabling us to create an inexpensive, lightweight cellular CFRP core, which wouldn’t be possible without the spread tow technologies.” The resulting core material also provides zero CTE, essential for optical precision in high-resolution imaging systems.

Manufacturable, modular structures, lower cost

This approach results in accessible and modular space structures, with potential applications including optical benches, solar array substrates, reflectors, deployable booms and spacecraft building blocks. Partners agree that the materials offer unprecedented thermal stability for their form factor, also critical for high-resolution imaging systems.

“Optics and imaging are getting to the point where angstrom levels of displacement of the lenses affect the overall resolution,” explains Patz. “Thermal expansion ends up driving a lot of the design. That’s why a lot of the large satellites use extremely expensive materials to get the CTE dialed in. This is a solution to accomplish similar attributes, but at a much more cost-effective price point.”

With performance goals met, the other hurdle this material approach helps to conquer is cost. Fewer layers mean fewer materials needed, fewer labor hours and a more streamlined manufacturing process, all contributing to lower costs. In addition, HM63 is a domestic fiber, which can also help avoid incurring additional costs due to tariffs, avoid export control and end user approval delays and ensure supply availability.

“The manufacturability ends up being a very big cost driver, because you rapidly manufacture these using standard press curing,” says Patz. “Just roll it out, put it in a press, keep pressure applied and you’ve got zero CTE facesheets that are HM.”

This improved manufacturability offers a significant advantage for the companies producing hundreds of satellites annually. “One of the interesting areas that we’re working with our customers on is inventory management,” says Patz. “They can now make a bunch of these panels even before they have a design, and then just take the panels out of inventory, trim, machine and assemble. Now your turn and burn time from design to manufacturing is weeks instead of years.”

Off the shelf and into space

RWC is looking to leverage this material in two main product lines: solar array substrates and high-volume reflectors. Jeremy Senne, director of the space structures segment at RWC, notes that the company aims to produce more than 100 reflectors annually using composites — a major leap over current industry benchmarks.

Solar array panels are typically constructed of ultra-thin HM three- to six-ply skins (~0.010-0.020 inch) with low-density core to minimize weight and maximize the power generation surface area for the spacecraft. For some designs, these skins are unbalanced layups that are pre-cured before panel consolidation, meaning that in a free state they take on a significant curvature until they are balanced by symmetry about the core. The HM63 QISO fabric enables these skins to be a single ply that is HM and quasi-isotropic, which reduces total manufacturing touch labor by 10-20%, cuts lead time and eliminates the challenges associated with thin, unbalanced pre-cured skins.

Reflectors are typically also constructed of thin, HM fabric skins with low-density core to minimize weight and maximize RF communication-related surface area. Skins are typically a minimum of two plies of fabric to maintain quasi-isotropic structural properties and avoid polarization associated with UD materials. Similar to the solar array panels, HM63 QISO fabric enables reflector skins to maintain equivalent weight and skin thickness of heritage designs, but in a single ply that is HM and quasi-isotropic, reducing manufacturing touch labor and lead time.

Testing and trials

Through testing (Fig 1, Table 1), RWC has demonstrated that panels built from HM63 QISO fabric have near-equivalent performance in strength, stiffness, CTE and RF reflectivity as those made using heritage materials.  This can be seen in panel structural test and RF reflectivity test results as shown in Table 2.

Tension and compression modulus and compression strength for the HM63 QISO fabric were similar to the conventional quasi-isotropic HM63 skins despite the fabric architecture. Flatwise strength was also similar, though the pre-cured skins exhibited a slightly lower value. In general, RWC concluded that, while more testing may be necessary for full qualification, the HM63 QISO fabric can be substituted for traditional uni-tape skins for this type of panel and match typical design driving properties.

RWC has also performed RF reflectance testing on a bare, uncoated HM63 QISO fabric sandwich panel to ensure that similar performance can be achieved with other reflector materials, and that the tri-directional weave does not result in any polarization challenges. Initial testing and compared to a baseline of polished copper from 2-16 gigahertz for both transverse electric (TE) and transverse magnetic (TM) poles (Figs 2-3, p. 35) covering S-band, C-band, X-band and Ku-band frequencies. Analyzing both TE and TM results enables characterization of the material’s optical properties and its potential for various applications.

Test data showed that, relative to copper, the HM63 QISO reflector exhibits between -0.2 and -0.6 decibel loss in this frequency range regardless of angle of incidence between 10° and 60°, and an axial ratio close to 1. According to RWC, this data gives a strong indication that the material will perform well for reflectors in an uncoated state for this frequency range. RWC will next perform testing at 16-40 gigahertz to characterize performance in other critical RF frequency bands.

RWC also performed a manufacturing trial to demonstrate a single-cure process for a reflector using the HM63 QISO fabric material. The fabric demonstrated it had enough drapeability to be a single un-spliced ply for both skins. The material was co-cured with PMT’s 1.6 pound per cubic foot Apex HM carbon core and then machined using conventional processes used on heritage reflector designs. No manufacturability concerns were identified, and the material was demonstrated to be a good candidate for these types of structures. In addition, reflector ply cutting and layup time was reduced from 2-3 days down to a single day for multi-ply skin designs.

Streamlined qualification and high-volume readiness

The use of composites for space is nothing new. However, recent breakthroughs in composite technology are rewriting the rules and companies like PMT, RWC and A&P are helping to usher in a new standard for satellite materials — one that aligns with the speed, cost and performance demands of today’s commercial space race. From enabling deployable structures to advancing thermal stability for optical systems, their innovations are laying the foundation for the next generation of spacecraft — and with standardization and inventory-ready panels, design-to-production cycles can be slashed from months to mere weeks.

Lowering material and manufacturing costs also means less risk involved for small satellite programs, which helps streamline the path to qualification of materials. What once took 8-10 years to qualify for legacy satellite platforms can now be achieved in as little as 1 year. This streamlined qualification process is vital for commercial satellite companies, which must bring hundreds of satellites online each year. As the commercial space industry continues to evolve, these innovative composite materials represent a significant leap forward, promising more accessible, efficient and sophisticated satellite technologies, making the final frontier more accessible than ever before.