Can LED Light Sources Serve as the "Sun" for Commercial Aerospace?

Commercial aerospace has witnessed explosive growth in recent years. Satellites, spacecraft and space stations, regardless of their orbital altitude, are all equipped with an on-board "power bank" — the space power supply. Most spacecraft run on solar energy, and solar arrays act as their vital power-generating core.

Here comes a critical question: how do engineers guarantee the reliability of solar cells intended for space operation? The answer lies in rigorous ground testing, for which solar simulators are the primary test hardware. These devices recreate the illumination conditions of space sunlight using artificial ground-based lighting.

This raises a new technical question: can LED light sources function as such artificial "simulated sun"?

Conclusion up front: Yes, and LED solutions are gaining rapid traction within the industry. However, several technical hurdles must be overcome for qualified performance.

LEDs deliver tangible advantages. First is long operational lifetime. Conventional xenon lamps typically offer only around 1 000 operating hours. Long-term operation causes electrode darkening and performance degradation, while lamp replacement incurs high costs and lengthy downtime. In contrast, LEDs generally achieve service lifetimes of tens of thousands of hours, barely affected by on-off cycling, substantially cutting maintenance expenditure.

Second, LEDs support instant readiness. Xenon lamps require lengthy warm-up periods before output stabilizes. By comparison, LEDs reach target spectrum and irradiance immediately upon power-on, enabling immediate testing and significantly boosting production-line efficiency.

Third, LEDs provide exceptional controllability. Individual wavelength bands can be adjusted independently. Target spectral regions and irradiance levels can be precisely configured — a level of flexibility that xenon-lamp systems cannot match.

Fourth, LEDs produce less heat, consume lower power and operate without high-voltage circuits, enhancing safety for both test facilities and operating personnel.

That said, formidable technical challenges persist. The primary bottleneck is spectral matching. Space-grade solar cells are designed for the AM0 extraterrestrial solar spectrum, which differs notably from the terrestrial AM1.5 spectrum, especially in the infrared region. Many high-efficiency space solar cells adopt germanium or indium gallium arsenide substrates with spectral response extending beyond 1 500 nm. Yet numerous LED solar simulators suffer degraded output near 1 100 nm. Insufficient infrared energy starves the bottom sub-cells, leading to severely distorted test measurement results.

A second limitation originates from device manufacturing constraints. LED peak wavelengths are selected from commercially available off-the-chip components and may not perfectly hit target spectral points. Moreover, LED spectra drift with driving power and operating temperature, with control tolerance at several nanometers.

Third concern concerns irradiance uniformity. LEDs feature wide emission angles. When numerous LED units are assembled into an array, irradiance uniformity degrades between the center and edges of the illuminated spot, posing major difficulties for testing large-area solar panels.

(Case reference: Aijiang Technology LED Solar Simulator)

Therefore: can LED solar simulators be deployed for space power-supply testing within commercial aerospace? The answer is yes — under proper conditions. Driven by long service life, flexible spectral tuning and instant-on operation, LED technology represents a major industry trend. Further technical competition centers on extending infrared spectral coverage and achieving accurate, stable AM0 spectral matching. This has become a key competitive frontier among domestic solar-simulator manufacturers: only systems faithfully reproducing the full AM0 solar spectrum are qualified to validate the performance of commercial aerospace’s vital power-generation core.

To be continued in our next article!