Heliofold | SCPI Film for LEO Solar Cell Protection

Product Overview

A transparent SCPI film for space solar cell protection.

Heliofold™ SCPI Film is supplied as the material for spacecraft solar cell protection stacks. It is intended for customers evaluating lightweight optical shielding, environmental protection, and flexible encapsulation routes in Low Earth orbit.

SCPI is a transparent polyimide protection layer that can be integrated by cell manufacturers, solar array integrators, and satellite developers.

Optical windowHigh visible transmittance and low haze support light access to the cell in selected photovoltaic stack designs.
Environmental shieldThe material is developed around LEO stressors including atomic oxygen, ultraviolet exposure, proton irradiation, thermal shock, and thermal cycling.
Encapsulation layerIn front/back protection concepts, SCPI can serve as part of a flexible encapsulation route for cells, interconnects, and adjacent components.

SCPI should be evaluated at stack level. Cell type, adhesive route, coating configuration, bend radius, electrical stringing, and mission qualification remain customer or integrator defined.

Transparent SCPI film sample under controlled handling — **SCPI film sample**

Application Note

SCPI enables lightweight integrated encapsulation for LEO solar arrays.

Heliofold™ SCPI Film is positioned as a transparent, space-grade polyimide layer for front/back solar-cell protection. It combines optical access, environmental shielding, and mechanical compliance in a film-led architecture for lightweight, flexible, and highly integrated space-PV stacks.

SCPI architecture premise

The SCPI application case centers on dual sided film encapsulation for LEO solar-cell stacks. In this concept, front SCPI can act as an optical window and environmental shield, while back SCPI can serve as a substrate or rear-side protective layer.

This integrated film route helps enclose cells, solder joints, interconnects, cables, diodes, and adjacent components. It reduces directly exposed interfaces and supporting long-term durability under atomic oxygen, ultraviolet exposure, particle radiation, thermal shock, and thermal cycling.

For compatible cell platforms, the transparent front/back concept can also support bifacial or albedo-aware designs, allowing both direct solar illumination and Earth reflected light to be considered during stack-level power and layout optimization.

Heliofold™ SCPI film provides a lightweight, highly flexible encapsulation solution for advanced space PV architectures. By solving key mass and deployment bottlenecks, it directly enables the scalable manufacturing required for modern commercial LEO constellations.

Technical Data

Heliofold™ SCPI Technical Specifications

Optical screening

89.5 ± 0.5% transmittance at 550 nm, 0.1% haze, and 0.08 yellowness index support early optical-window evaluation.

Mechanical / thermal

25 μm-class thickness, 210 MPa tensile strength, 9.7 GPa modulus, 315°C Tg, and 22 ppm/°C CTE frame the mechanical design window.

LEO exposure

AO erosion yield, UV cutoff wavelength, and IR emissivity provide starting points for space-environment evaluation.

Property	Unit	SCPI value	Test method
Geometry and optical properties
Thickness	μm	25 ± 1.0	GB/T 6672
Density	g/cm³	1.4	ASTM D792-08
Refractive index	—	1.575	ASTM D542-00
Transmittance at 550 nm	%	89.5 ± 0.5	GB/T 2410
Yellowness index	—	0.08	ASTM E313-10
Haze	%	0.1	GB/T 2410
Surface roughness	nm	< 1	ISO 25178
Mechanical and thermal properties
Tensile strength	MPa	210	ISO 527-1 / GB/T 1040.1
Elongation at break	%	20	ISO 527-1 / GB/T 1040.1
Elastic modulus	GPa	9.7	ISO 527-1 / GB/T 1040.1
Thermal shrinkage	%	±0.3	ASTM D2305
Glass transition temperature	°C	315	GB/T 40396
Coefficient of linear thermal expansion	ppm/°C	22	ASTM E831-06
Electrical and environmental properties
Surface resistivity	Ω/sq	>10¹³	ASTM D257-91
Volume resistivity	Ω·cm	>10¹⁴	ASTM D257-91
Atomic oxygen erosion yield	cm³/atom	6.41 × 10⁻²⁶	—
UV cutoff wavelength at 50% transmittance	nm	388	—
Infrared emissivity	—	0.85	ASTM E408-13

Evaluation Scope

Use SCPI in a stack-level qualification plan.

A credible SCPI discussion should start from the customer’s orbit, cell platform, integration route, adhesive system, bend mechanics, and qualification timeline.

Orbit / Exposure

Define AO fluence, UV dose, proton or particle exposure, eclipse profile, and thermal-cycle range before selecting a stack route.

Cell Platform

Screen compatibility with silicon, III–V multi-junction, CIGS, perovskite, or customer-specific cell systems.

Interface Route

Specify adhesive, surface preparation, coating stack, curing process, and cleanliness requirements before adhesion testing.

Mechanical Design

Define bend radius, stowed volume, folding or roll-out assumptions, handling process, and mechanical strain limits.

Optical Retention

Track transmittance, haze, yellowing, reflectance, and spectral changes after environmental exposure and thermal cycling.

System Boundary

Deployment hardware, electrical architecture, stringing, array-level power output, and mission qualification are not claimed by the film page.

SCPI Samples

Sample photographs.

These photographs are used to show SCPI film form factor and visual identity.

Free-standing SCPI film sample on a dark surface — Free-standing SCPI film coupon

SCPI flexible film sample held by a gloved hand — Flexible SCPI sample under bending

Discuss Your Solar Cell Protection Stack

Tell us your orbit, cell type, required thickness, optical target, thermal range, and integration route. Heliofold can provide SCPI film, compatible silicone adhesives, and selected cover glass materials for evaluation.

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