Rock West solar panelThis panel is a stiff, light base for solar cells in geostationary orbit, built from carbon fibre and aluminium.
rockwest-geo-solar-array-panel Rockwest Composites sells this flat panel as a base for solar cells. It is made for arrays in geostationary orbit, medium Earth orbit and deep space. It measures 48 by 96 inches (1219.2 by 2438.4 millimetres) but is only 0.272 inches thick. Each order comes with a certificate package.
Two thin skins of carbon fibre sandwich an aluminium honeycomb core. Each skin is 0.008 inches thick. The fibre is Toray M55J, a stiff, high-modulus type, and the resin is a toughened cyanate ester. The layers are laid in a quasi-isotropic pattern, with the fibre direction turned from layer to layer.
A lightweight, stiff backing panel for geostationary-orbit solar arrays. An aluminium honeycomb core between carbon-fibre skins carries the solar cells, with a Kapton surface to bond them to. It helps array designers who need high stiffness at very low mass.
The two skins carry the bending load. Each one is cured on its own in an autoclave, a heated pressure vessel. The finished panel is then consolidated under a vacuum bag in an oven.
The core is perforated aluminium honeycomb, 0.25 inches thick. Cytec FM300-2 film adhesive bonds it to the skins. Rockwest says the perforated core and the film adhesive are combined to tune the panel's bending stiffness.
A Kapton film 0.002 inches thick is cured together with the skin on one face. It is the surface the solar cells are bonded to, and the cells themselves are not part of the product. Both faces of the panel are finished matte black.
Every order includes a certificate package with dimensional inspection, material certificates, traceability and a statement of verification. Extra tests can be ordered, among them short-beam shear, flatwise tension and long-beam flexure on the sandwich, and resin-content tests on the skins.
The fibre in both face skins.
The resin that holds the fibres together in the skins.
A 0.002 inch layer on one face, where the solar cells are bonded.
The perforated core, 0.25 inches thick.
Bonds the core to the skins.
Both faces of the panel.
This panel is a sibling of Rockwest's low-Earth-orbit substrate, which has the same size and core but a different resin. Toray supplies the carbon fibre, Patz the resin and Cytec the adhesive. Rockwest says every material in its STRATO range meets NASA and ESA outgassing requirements, the limits on gas released in a vacuum. It names no mission that has used this panel.
The Kapton layer is the solar-cell bonding substrate; cells are not part of the product
Rockwest Composites
Sibling in the STRATOSubstrate line: same size and core, LEO resin system instead of the GEO cyanate ester
Rockwest Composites
Sibling in the STRATOSubstrate line: same size and core, GEO cyanate ester system
PMT-F33 resin outgassing data on the supplier datasheet
Maker's claim for all STRATO materials
Fibre of the skins; datasheet CFA-017
Resin of the skins
Core-to-skin film adhesive
Rockwest Composites
Carbon fibre. Here: Face skin carbon fibre; Face skin laminate pair (2 x 0.008 in), STRATOplateGEO and more. There: Face skin carbon fibre; HR40 / NB321 unidirectional prepreg and more.
Kapton film. Here: Kapton edging on STRATOSubstrate panels. There: Kapton edging on STRATOSubstrate panels.
Kapton HN polyimide film. Here: Kapton film, co-cured to one skin face. There: Kapton film, co-cured to one skin face.
Matte black finish. Here: Panel surfaces (both faces). There: Panel surfaces (both faces).
Aluminium honeycomb core. Here: Core. There: Core.
ESA
Carbon fibre. Here: Face skin carbon fibre; Face skin laminate pair (2 x 0.008 in), STRATOplateGEO and more. There: Platform structure supplier (eoPortal).
Aluminium honeycomb core. Here: Core. There: H-configuration inner panels (3); Outer panels without cells and more.
ESA
Carbon fibre. Here: Face skin carbon fibre; Face skin laminate pair (2 x 0.008 in), STRATOplateGEO and more. There: Outer panels (3).
Aluminium honeycomb core. Here: Core. There: Structure (summary).
NASA / JPL
Carbon fibre. Here: Face skin carbon fibre; Face skin laminate pair (2 x 0.008 in), STRATOplateGEO and more. There: Rotor blades (upper and lower); Rotor primary structure and more.
Kapton film. Here: Kapton edging on STRATOSubstrate panels. There: Battery heaters.
SpaceX
Carbon fibre. Here: Face skin carbon fibre; Face skin laminate pair (2 x 0.008 in), STRATOplateGEO and more. There: Interstage face sheets; Landing legs.
Aluminium honeycomb core. Here: Core. There: Interstage; Fairing shell (aluminium honeycomb with carbon fibre face sheets).
SpaceX
Carbon fibre. Here: Face skin carbon fibre; Face skin laminate pair (2 x 0.008 in), STRATOplateGEO and more. There: Landing legs (Falcon 9 booster).
Aluminium honeycomb core. Here: Core. There: Interstage (Falcon 9); Centre-core interstage (4.5 m).
The page shows a weight with no unit, so the panel's mass isn't clear. Rockwest publishes no thermal, expansion, stiffness or strength figures for the finished panel. The Kapton grade and supplier are not named, and the exact order and angles of the layers are shared only under a non-disclosure agreement. Nor does Rockwest say whether this panel has flown.
What is written above is built from these numbers and quotes. Each row links to the page it was taken from. Get all of it as JSON, or ask our MCP server.
| What | Value |
|---|---|
| Size | 48 in x 96 in (1219.2 mm x 2438.4 mm) |
| Core material | Aluminium honeycomb (perforated) |
| Core thickness | 0.25 in |
| Core density | 2.3 pcf |
| Colour / finish | Black, matte on both sides |
| Length tolerance | +/- 0.125 in |
| Width tolerance | +/- 0.125 in |
| Skin thickness tolerance (each) | +/- 10% |
| Core thickness tolerance | +/- 0.010 in |
| Flatness | 0.040 in (0.010 per 12 x 12 in) |
| Application | Space and stable structures |
| Panel thickness | 0.272 in |
| Skin thickness (each) | 0.008 in |
| Max suggested use temperature | 300 F (150 C) |
| Target orbits | Medium Earth Orbit, Geostationary Orbit, deep space |
| Skin fibre modulus | 78 Msi (M55J) |
| Skin layup | Quasi-isotropic |
| Cure process | Skins autoclave cured individually; panels vacuum bag/oven consolidated |
| M55J fibre tensile modulus | 78.2 Msi (540 GPa) |
| M55J fibre density | 1.91 g/cm3 |
| PMT-F33 / M55J laminate, 0-degree tensile strength (60 % fibre volume) | 310 ksi |
| PMT-F33 / M55J laminate, 0-degree tensile modulus | 48.5 Msi |
| PMT-F33 recommended cure | 350 F for 4 hours (autoclave, 80 psi) |
| PMT-F33 storage life | 1 year below 10 F; handling life 30 days at 75 F |
| PMT-F33 dielectric properties | Dk/Df 2.75/0.003 at 3 GHz |
| Resin system use limit (STRATOplateGEO) | 450 F (230 C) for the plate |
| Constellation experience (maker claim) | 38 plus satellites |
Each material named in the sources: where it is used here, which other products use it, and its key numbers when its material page exists.
Used in 5 partsFace skin carbon fibre · Face skin laminate pair (2 x 0.008 in), STRATOplateGEO · Toray M55J fibre, 6K untwisted tow, sizing 50B · +2 more
Used in 2 partsFace skin matrix resin · Patz PMT-F33 toughened cyanate ester resin system
Used in 1 partCore-to-skin film adhesive
Used in 1 partKapton edging on STRATOSubstrate panels
Used in 1 partKapton film, co-cured to one skin face
Used in 1 partPanel surfaces (both faces)
Used in 1 partCore
The page names the fibre, resin, adhesive, Kapton film and core of the sandwich panel, but gives no drawing, ply table or numbered parts list (technical drawing is NDA-only). Components, suppliers and links were added from public sources. A material is left blank where no source states it.
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Face skin carbon fibre“use M55J carbon fiber (78 Msi) with PMT-F33 cyanate ester resin in a quasi-isotropic layup” | Toray M55J high modulus fiber (78 Msi)carbon-fibre | — | Toray M55J datasheet No. CFA-017 |
| Face skin matrix resin“use M55J carbon fiber (78 Msi) with PMT-F33 cyanate ester resin in a quasi-isotropic layup” | Patz PMT-F33 cyanate ester resincyanate-ester-pmt-f33 | — | Patz PMT-F33 datasheet |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Kapton film, co-cured to one skin face“0.002” Kapton film co-cured to one face” | Kapton film, 0.002 inpi-kapton-hn | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Core“2.3 Pcf AL Core - 0.25 Inch Thick” | Perforated aluminum honeycombaluminium-honeycomb-hexweb | — | Panel P/N 22Z002103-K1-4-R-2.3-0.250-P-0.250-A |
| Core-to-skin film adhesive“Cytec FM300-2 film adhesive.” | Cytec FM300-2 film adhesivefm300-2-film-adhesive | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Panel surfaces (both faces)“Color Black Finish Matte / Matte” | Matte black finish (colour Black, finish Matte / Matte)matte-black-finish | Matte / Matte | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Face skin laminate pair (2 x 0.008 in), STRATOplateGEOTwo co-cured-Kapton skins that carry the bending load; autoclave cured individually“Skins are autoclave cured individually and sandwich panels are then vacuum bag/oven consolidated.” | M55J carbon fibre / PMT-F33 cyanate ester, quasi-isotropiccarbon-fibre | — | Supplier: Rock West Composites |
| Toray M55J fibre, 6K untwisted tow, sizing 50BHigh-modulus fibre of the skins as described on the maker's datasheet CFA-017“MJ type high modulus fiber with enhanced tensile and compressive strength over M series fibers” | Carbon fibre (M55J)carbon-fibre | — | Supplier: Toray Carbon Fibers America |
| Patz PMT-F33 toughened cyanate ester resin systemSkin matrix; medium/dry tack; vacuum bag, press or autoclave cure“PMT-F33 is a toughened cyanate ester resin system” | Cyanate ester (PMT-F33)cyanate-ester-pmt-f33 | — | Supplier: Patz Materials and Technology |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| STRATOplateGEO laminate 0.044 in (P/N 22Z002102-3-0.044-96-48)Stock plate of the same M55J / PMT-F33 quasi-isotropic system, 96 x 48 in; autoclave cured, use limit 450 F (230 C)“STRATOplateGEO laminates are autoclave cured.” | M55J carbon fibre / PMT-F33 cyanate estercarbon-fibre | — | Supplier: Rock West Composites |
| STRATOplateGEO laminate 0.089 in (P/N 22Z002102-5-0.089-96-48)Thicker stock plate of the same system“Laminate - Space Grade - M55J - Cyanate Ester - Quasi-iso Unidirectional - 96.0 x 48.0 x 0.089 inch” | M55J carbon fibre / PMT-F33 cyanate estercarbon-fibre | — | Supplier: Rock West Composites |
| STRATOsubstrate GEO variant with 0.017 in skins (P/N 22Z002103-K5-4-R)Sibling GEO substrate: M55J skins 0.017 in, FM300-2, 0.289 in thick“Substrate - Space Grade - Kapton Surface - M55J - Cyanate Ester - 0.017" Thick Skins - FM300-2 Film Adhesive” | Not said | — | Supplier: Rock West Composites |
| STRATOPanel GEO sandwich panels, 1.0 in thick, 3.1 pcf core (0.022 in and 0.045 in skins)Thicker M55J / cyanate ester sandwich panels with FM300-2 film adhesive“Panel - Space Grade - M55J - Cyanate Ester - 0.022" Thick Quasi-Iso Skins - FM300-2 Film Adhesive” | Not said | — | Supplier: Rock West Composites |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Certificate packageDimensional inspection, material certificates, traceability and statement of verification, per order“Each space grade order includes a certificate package with dimensional inspection, material certificates, traceability, and a statement of verification.” | Not said | — | Supplier: Rock West Composites |
| Full traveler verification (option)Copies of out-time tracking, ply angle and cure verifications, per panel“Include Full Traveler Verification (Per panel. Includes out time tracking, ply angle, and cure verifications)” | Not said | — | Supplier: Rock West Composites |
| Short beam shear test coupons (option)Three tests per batch, ordered with the first order“Short beam shear testing (3 tests per batch. Must be ordered at time of initial order.)” | Not said | — | Supplier: Rock West Composites |
| Flatwise tension and long beam flexure tests on the sandwich (option)Panel-level mechanical tests offered with the order“flatwise tension testing and long beam flexure testing on the sandwich panel” | Not said | — | Supplier: Rock West Composites |
| Resin content tests on the face skins (option)Up to three tests per face skin“resin content testing (up to three tests per face skin available)” | Not said | — | Supplier: Rock West Composites |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Kapton edging on STRATOSubstrate panelsKapton along the panel edge, seen on DiskSat panel images“Shows Kapton edging and metallic inserts” | Kapton film (grade not stated for the edging)kapton-film-grade-unstated | — | Supplier: Rock West Composites |
| Precision metallic insertsInserts bonded into the sandwich panel for mounting; shown on the DiskSat panel images“Image shows exposed aluminum core, precision inserts and Kapton edging” | Not said | — | Supplier: Rock West Composites |
| Cup/cone fittings (match-bonded in solar wings)Fittings that stack panels into deployable solar array wings“Our team excels at precision assembly and match bonding of cup/cone fittings.” | Not said | — | Supplier: Rock West Composites |
The page cites no material or process specification (no AMS/ASTM/ECSS callout) for the fibre, resin, adhesive, Kapton or core. The aluminium honeycomb alloy and cell size, the Kapton grade and the 'reticulated' adhesive form are not specified beyond the title. Technical drawing, layup and cure details are only available under NDA. Ply count and orientation table is not shown. Solar cell, adhesive for cells and mounting inserts are not part of this product. More detail: Not published: panel mass with a unit (the page shows Weight 8.67 with none), insert specification, whether this GEO part has flown, adhesive thickness, honeycomb alloy and cell size, Kapton grade (the LEO release says HN for that product), ply-by-ply layup (drawing under NDA). The edging, insert and cup/cone items come from Rock West solar-array pages and DiskSat images (a LEO product), not from this GEO product page. No GEO mission is named for this substrate. More detail: Not published: panel mass with a unit (the page shows Weight 8.67 with none), insert specification, whether this GEO part has flown, adhesive thickness, honeycomb alloy and cell size, Kapton grade (the LEO release says HN for that product), ply-by-ply layup (drawing under NDA). The edging, insert and cup/cone items come from Rock West solar-array pages and DiskSat images (a LEO product), not from this GEO product page. No GEO mission is named for this substrate.
Collected from public pages and documents, checked 4 Nov 2026.
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