This panel is a stiff, light base for solar cells in low Earth orbit, built from carbon fibre and aluminium.
rockwest-solar-array-substrate Rockwest Composites makes this panel to order as a base for solar arrays in low Earth orbit. It is 48 by 96 inches (1219.2 by 2438.4 millimetres) and 0.295 inches thick. A Kapton film on one face is the surface the solar cells are bonded to. Rockwest says it can supply the panel on a short lead time.
The skins are Mitsubishi HR40 carbon fibre in NB321 epoxy, 0.020 inches thick each, around a perforated aluminium honeycomb core. Rockwest suggests a top use temperature of 225 °F (107 °C). Its sibling for higher orbits, built on a cyanate ester resin, goes up to 300 °F (150 °C).
A Kapton-surfaced aluminium honeycomb substrate with carbon-fibre epoxy skins, made to order for solar arrays. It gives array builders a stiff, light base with full material-lot traceability.
Each skin is 0.020 inches thick. The layers are laid up in a quasi-isotropic pattern and oven cured one skin at a time. Rockwest calls the NB321 resin a high-temperature epoxy.
Between the skins sits a perforated aluminium honeycomb core, 0.25 inches thick. Newport NB301 film adhesive bonds core and skins. Rockwest says the perforated core and the film adhesive together tune the bending stiffness.
One face carries a 0.002 inch Kapton film, cured together with the skin, for bonding solar cells. The cells are not included. Both faces are finished matte black.
DiskSat is a one-metre-wide spacecraft from The Aerospace Corporation. For it, Rockwest built four assemblies from blanks of this substrate, with aluminium inserts primed with BR-127 and bonded in with EA9394 adhesive. The insert design locates itself, so no costly assembly fixture is needed, and positional tolerances run from 0.010 to 0.020 inches.
The fibre in both face skins.
The resin in the skins, which Rockwest calls a high-temperature epoxy.
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.
The primed inserts bonded into the DiskSat assemblies. The alloy is not given.
Four DiskSat spacecraft flew on a Rocket Lab Electron in December 2025. Rockwest's release and image captions tie its assemblies to the programme, but Aerospace's own fact sheet names no panel supplier. Rockwest also built custom panels, with skins supplied by the customer, for the 500-watt arrays on Astro Digital's Corvus satellite buses.
Rock West shipped four STRATOSubstrate LEO based solar array substrate / back-up structure assemblies to The Aerospace Corporation for the DiskSat program
Custom SAS panels delivered June 2024 for higher-power Corvus buses; the release says the first would launch in October (year not stated)
The Kapton layer is the solar-cell bonding substrate; cells are not part of the product
Rocket Lab
Four DiskSat spacecraft flew on Electron; Aerospace does not name the substrate supplier, the Rock West link is the release and image captions
Rockwest Composites
Sibling in the STRATOSubstrate line: same size and core, GEO cyanate ester system
Rockwest Composites
Sibling in the STRATOSubstrate line: same size and core, LEO resin system instead of the GEO cyanate ester
Maker's claim for all STRATO materials
Rockwest Composites
Carbon fibre. Here: Face skin carbon fibre; HR40 / NB321 unidirectional prepreg and more. There: Face skin carbon fibre; Face skin laminate pair (2 x 0.008 in), STRATOplateGEO 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; HR40 / NB321 unidirectional prepreg and more. There: Platform structure supplier (eoPortal).
Aluminium. Here: Aluminium inserts, in-plane and out-of-plane (DiskSat build). There: TPMU/DSLP housing.
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; HR40 / NB321 unidirectional prepreg and more. There: Outer panels (3).
Aluminium. Here: Aluminium inserts, in-plane and out-of-plane (DiskSat build). There: Telescope (structure and mirrors, 3 telescopes).
Aluminium honeycomb core. Here: Core. There: Structure (summary).
PSAS / Oregon State
Aluminium. Here: Aluminium inserts, in-plane and out-of-plane (DiskSat build). There: Backplane grounding to frame.
Copper. Here: Copper traces in the skins. There: Helical antenna (+Z end card); Outer copper foil and more.
Kapton HN polyimide film. Here: Kapton film, co-cured to one skin face. There: Polyimide thermofoil heater (Minco, 2 per card); Heater tape.
North American Aviation
Aluminium. Here: Aluminium inserts, in-plane and out-of-plane (DiskSat build). There: Radial beams; Crushable ribs (x4) and more.
Aluminium honeycomb. Here: Aluminium honeycomb core and metallic inserts (Astro Digital panels). There: Inner pressure shell (crew compartment); Sector and RCS exterior panels (1 in thick).
G10 fiberglass laminate. Here: G10 fiberglass skins with integrated copper traces. There: Thruster outer wrap.
NASA / JPL
Carbon fibre. Here: Face skin carbon fibre; HR40 / NB321 unidirectional prepreg and more. There: Rotor blades (upper and lower); Rotor primary structure and more.
Copper. Here: Copper traces in the skins. There: Rotor motor windings; Wiring through mast to ECM.
Kapton film. Here: Kapton edging on STRATOSubstrate panels. There: Battery heaters.
The page shows a weight with no unit, so the panel's mass isn't clear. Rockwest publishes no thermal or mechanical figures for it, and the exact layer-by-layer layup is shared only under a non-disclosure agreement. The Kapton grade is not named. Rockwest's DiskSat release and Aerospace's fact sheet give very different thicknesses for the finished assembly.
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 | 0.295 in |
| Skin thickness (each) | 0.020 in |
| Max suggested use temperature | 225 F (107 C) |
| Target orbit | Low Earth Orbit |
| Skin fibre modulus | 57 Msi (HR40) |
| Skin layup | Quasi-isotropic |
| Cure process | Skins oven cured individually; panels vacuum bag/oven consolidated |
| DiskSat assembly size (release) | about 1 m diameter; release says 25 cm thick, Aerospace fact sheet says 2.5 cm |
| DiskSat insert positional tolerance | 0.010 to 0.020 in on in-plane and out-of-plane inserts, global datum scheme |
| DiskSat demonstration mission launch | December 2025 on Rocket Lab Electron, four spacecraft |
| DiskSat structure (Aerospace fact sheet) | carbon-fibre composite sandwich, about 13.5 kg, 1 m diameter by 2.5 cm |
| DiskSat power (Aerospace fact sheet) | more than 100 W |
| Astro Digital panels size | about 2 ft x 2 ft |
| 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 · HR40 / NB321 unidirectional prepreg · Face skin laminate pair (2 x 0.020 in), STRATOplateLEO · +2 more
Used in 1 partAluminium inserts, in-plane and out-of-plane (DiskSat build)
Used in 1 partAluminium honeycomb core and metallic inserts (Astro Digital panels)
Used in 1 partBR-127 primer on the inserts
Used in 1 partCopper traces in the skins
Used in 1 partEA9394 insert bonding adhesive
Used in 1 partG10 fiberglass skins with integrated copper traces
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-to-skin film adhesive
Used in 1 partFace skin matrix resin
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 HR40 carbon fiber (57 Msi) with NB321 high temperature epoxy resin in a quasi-isotropic layup” | Mitsubishi HR40 high modulus fiber (57 Msi)carbon-fibre | — | Mitsubishi HR40 |
| Face skin matrix resin“use HR40 carbon fiber (57 Msi) with NB321 high temperature epoxy resin in a quasi-isotropic layup” | Newport 321 epoxy resin (NB321 high temperature epoxy)newport-nb321-epoxy-resin | — | Newport NB321 |
| 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-K25-1-UR-2.3-0.250-P-0.250-V |
| Core-to-skin film adhesive“Newport 301 film adhesive.” | Newport 301 film adhesive (NB301)newport-nb301-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 |
|---|---|---|---|
| HR40 / NB321 unidirectional prepregPrepreg form of the skin material, laid up quasi-isotropic and oven cured individually“STRATOSubstrate LEO class panels use HR40/NB321 unidirectional prepreg, NB301 film adhesive, perforated aluminum honeycomb core, and 0.002” HN Kapton.” | Carbon fibre / epoxy prepreg (HR40 fibre, NB321 resin)carbon-fibre | — | Supplier: Rock West Composites |
| Face skin laminate pair (2 x 0.020 in), STRATOplateLEOTwo skins with a 0.002 in Kapton film co-cured to one face“The face skins are STRATOplateLEO plate with a 0.002” Kapton film co-cured to one face” | HR40 carbon fibre / NB321 epoxy, quasi-isotropiccarbon-fibre | — | Supplier: Rock West Composites |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Aluminium inserts, in-plane and out-of-plane (DiskSat build)Self-fixturing inserts that match a global datum scheme; positional tolerance 0.010 to 0.020 in“The inserts for the deliverable were BR-127 primed aluminum bonded with EA9394.” | Aluminium (alloy not stated), BR-127 primedaluminium | — | Supplier: Rock West Composites |
| BR-127 primer on the insertsPrimer applied to the aluminium inserts before bonding“The inserts for the deliverable were BR-127 primed aluminum bonded with EA9394.” | BR-127 primer (chemistry not stated)br-127-primer | — | Supplier: Rock West Composites |
| EA9394 insert bonding adhesiveAdhesive that bonds the primed inserts into the sandwich“The inserts for the deliverable were BR-127 primed aluminum bonded with EA9394.” | EA9394 adhesive (maker and chemistry not stated)ea9394-adhesive | — | Supplier: Rock West Composites |
| Back-up structure assemblies for DiskSat (4 delivered)Combination solar array substrate / back-up structure assemblies built to print from STRATOSubstrate LEO blanks, about 1 m in diameter“shipped the first four solar array substrate/back-up structure assemblies to The Aerospace Corporation in support of the DiskSat Program” | Not said | — | Supplier: Rock West Composites |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| STRATOplateLEO laminate 0.054 in (P/N 22Z002102-9-0.054-96-48)Stock plate of the HR40 / NB321 quasi-isotropic system, 96 x 48 in; vacuum bag / oven cured“STRATOplateLEO laminates are vacuum bag/oven cured, but autoclave cure may be available upon request.” | HR40 carbon fibre / NB321 epoxycarbon-fibre | — | Supplier: Rock West Composites |
| STRATOplateLEO laminate 0.108 in (P/N 22Z002102-11-0.108-96-48)Thicker stock plate of the same system“Laminate - Space Grade - HR40 - Epoxy - Quasi-iso Unidirectional - 96.0 x 48.0 x 0.108 inch” | HR40 carbon fibre / NB321 epoxycarbon-fibre | — | Supplier: Rock West Composites |
| STRATOsubstrate LEO variant with 0.010 in skins (P/N 22Z002103-K21-1-UR)Sibling LEO substrate: HR40 skins 0.010 in, NB301, 0.275 in thick“Substrate - Space Grade - Kapton Surface - HR40 - Epoxy - 0.010" Thick Skins - NB301 Film Adhesive” | Not said | — | Supplier: Rock West Composites |
| STRATOPanel LEO sandwich panels, 1.0 in thick, 3.1 pcf core (0.027 in and 0.054 in skins)Thicker HR40 / epoxy sandwich panels with NB301 film adhesive“Panel - Space Grade - HR40 - Epoxy - 0.027" Thick Quasi-Iso Skins - NB301 Film Adhesive” | Not said | — | Supplier: Rock West Composites |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Sandwich panels with customer-furnished trace/lead integrated skins (about 2 ft x 2 ft)Custom SAS panels, not the stock STRATOsubstrate: face skins carry copper traces for direct solar cell integration“RWC built the sandwich panels from trace/lead integrated skins that allowed for direct integration with solar cells.” | Not said | — | Supplier: Rock West Composites |
| G10 fiberglass skins with integrated copper tracesSkins supplied by the customer“The customer furnished the G10 (fiberglass) skins that already had the integrated copper traces.” | G10 fiberglass laminate (resin not stated)fiberglass | — | — |
| Copper traces in the skinsElectrical traces for the solar cell strings“The customer furnished the G10 (fiberglass) skins that already had the integrated copper traces.” | Coppercopper | — | — |
| Aluminium honeycomb core and metallic inserts (Astro Digital panels)RWC used specialized tooling to align the skins on the core so the traces stay in place“RWC used specialized tooling to align the face skins on the aluminum honeycomb core” | Aluminium honeycomb (alloy not stated)aluminium-honeycomb | — | 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 for the fibre, resin, adhesive, Kapton or core. No datasheet PDFs are linked on this page (unlike the GEO panel). The aluminium honeycomb alloy and cell size and the Kapton grade are not stated. 'Unreticulated' adhesive appears only in the title. Technical drawing, layup and cure details are only available under NDA. More detail: The stock part page gives no mass with a unit (Weight 14.01 only), no HR40 or NB321 datasheet, no honeycomb alloy or cell size, no insert specification (the DiskSat release names BR-127 primer and EA9394 for that custom build only) and no layup (drawing under NDA). The DiskSat release is headed January 31, 2023 in the dateline but dated 2024 in the page header, and gives the assembly thickness as 25 cm while Aerospace gives the DiskSat as 2.5 cm thick, so that number is probably a typo and is reported as printed. The Aerospace fact sheet does not name Rock West or any solar-panel supplier, and the Astro Digital panels are custom parts with customer-furnished G10 skins, not the stock STRATOsubstrate. Kapton edging and cup/cone fittings come from Rock West solar-array pages, not the product page. More detail: The stock part page gives no mass with a unit (Weight 14.01 only), no HR40 or NB321 datasheet, no honeycomb alloy or cell size, no insert specification (the DiskSat release names BR-127 primer and EA9394 for that custom build only) and no layup (drawing under NDA). The DiskSat release is headed January 31, 2023 in the dateline but dated 2024 in the page header, and gives the assembly thickness as 25 cm while Aerospace gives the DiskSat as 2.5 cm thick, so that number is probably a typo and is reported as printed. The Aerospace fact sheet does not name Rock West or any solar-panel supplier, and the Astro Digital panels are custom parts with customer-furnished G10 skins, not the stock STRATOsubstrate. Kapton edging and cup/cone fittings come from Rock West solar-array pages, not the product page.
Rock West solar panel 
Official render 
Official render Collected from public pages and documents, checked 4 Nov 2026.
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