How to Choose Satellite Solar Cells: GaAs vs HJT vs Perovskite

Space photovoltaic (PV) power generation centers on the solar array — the "power heart" of a satellite that converts sunlight into electricity. But space is an unforgiving environment: vacuum, intense radiation, extreme temperature swings, and zero possibility of on-orbit repair. Solar cells destined for orbit must satisfy demands on conversion efficiency, radiation resistance, and lightweight design that ground-based applications could never imagine. Today, a handful of solar cell technologies have earned their place in space. Here is how to choose among them.

1. The Veteran: Silicon-Based Solar Cells

Early satellites relied mainly on monocrystalline and polycrystalline silicon cells — the solar wings of China’s Shenzhou-1 spacecraft, for example, used polycrystalline silicon. Silicon cells benefit from mature manufacturing processes and low cost, but their conversion efficiency reaches only about 18%, with low specific power and only moderate radiation tolerance. They have therefore largely withdrawn from high-power space missions and now survive mainly in low-cost small satellites.

2. The Workhorse: Gallium Arsenide (GaAs) Multi-Junction Cells

GaAs multi-junction cells are the undisputed mainstream of space photovoltaics today. Led by triple-junction structures such as GaInP/GaAs/Ge, they consistently deliver measured efficiencies above 30% under the AM0 (Air Mass Zero) standard solar spectrum, with production models reaching 34.5% and laboratory four-junction cells breaking through 47.6%. Combining high efficiency, long service life, and outstanding radiation resistance, they are the first-choice power source for geostationary (GEO) communication satellites, deep-space probes, and space stations. Their main drawbacks are complex manufacturing and high cost, with a per-cell price far higher than ground-based solar cells.

3. The Cost-Effective Contender: HJT Silicon Cells

Crystalline silicon heterojunction (HJT) cells follow the philosophy of "silicon-level cost, space-grade performance." Their large-area efficiency has already reached about 27%, setting a new world record, and the technology is ready for scaled-up mass production. Although slightly less efficient than GaAs, HJT offers dramatically lower costs, making it an important candidate for "affordable space photovoltaics" in the commercial space industry.

4. The Rising Star: Perovskite and Tandem Solar Cells

Perovskite is the biggest technological variable of recent years. Single-junction perovskite cells achieve roughly 18%–20% efficiency in space, while tandem architectures push the theoretical limit beyond 45%. Perovskites are thin, flexible, and lightweight, with high specific power and outstanding radiation tolerance, and they can be combined in tandem with silicon and GaAs. NASA has already launched long-term in-orbit validation of perovskite cells aboard the International Space Station, and perovskite modules developed in China have also flown in space, operating stably with an efficiency retention rate above 90%. Low cost plus light weight make perovskite the leading candidate to power next-generation low-Earth-orbit (LEO) constellations.

In Short

Gallium arsenide supports today’s missions, HJT brings the promise of affordability, and perovskite points to the future — three solar cell routes are reshaping the landscape of space photovoltaics.

Great Cells Demand Great Testing

Once a solar cell reaches orbit, it can never be repaired. Any efficiency degradation, micro-cracks, or radiation damage must be accurately identified before launch — and this is precisely where Aijiang Technology excels. Leveraging its AM0 solar simulator and the Xinghan AI 2.0 multimodal inspection system, Aijiang delivers end-to-end testing solutions for space power systems, covering everything from GaAs and perovskite solar cells to energy storage and power systems. Under the AM0 standard spectrum, it conducts rigorous inspection of efficiency, defects, and reliability, supporting the high-quality development of the commercial space industry.