Rocket Lab Releases Germanium-Free Solar Cell With 31.5% Efficiency

Rocket Lab Corporation has announced the production release of IMM Apex, the newest version of its Inverted Metamorphic solar cell for space applications. The cell delivers a Beginning of Life conversion efficiency of 31.5% and eliminates the germanium substrate used in conventional multi-junction cells, a shift the company says addresses rising costs and supply chain constraints in the space power industry.

IMM Apex builds on Rocket Lab's existing IMM cell technology, which powered NASA's Ingenuity Mars Helicopter and has operated on satellites in orbit for more than a decade. By removing the germanium substrate that has been standard in multi-junction cells for the past three decades, the company positions the product to mitigate constraints tied to that critical mineral.

The cell offers 40% lower mass than comparable products, giving it what Rocket Lab describes as best-in-class specific power measured in watts per kilogram, while maintaining radiation hardness and performance across temperature ranges. IMM Apex is a mechanical and electrical drop-in replacement for heritage solar cell products built on germanium, allowing customers to integrate it into existing systems without re-tooling for new cell technology. Optimized manufacturing processes and targeted capital investments have enabled production in multi-100-kilowatt volumes to meet growing demand.

"Rocket Lab is excited to bring this cutting-edge solar solution to market. IMM Apex delivers exceptional performance while addressing real-world challenges like rising material costs and supply chain constraints," said Brad Clevenger, President of Rocket Lab USA. "With IMM Apex, customers gain access to a high-efficiency, lightweight, germanium-free product that combines proven reliability with faster production times. IMM Apex is designed to more cost-effectively power the most ambitious missions without compromising performance."

The company states that IMM technology has undergone more than a decade of testing and qualification. Rocket Lab has provided space-grade solar technology to civil, national security and commercial programs including the James Webb Space Telescope and NASA's Artemis lunar explorations, along with interplanetary science missions. More than 1,100 satellites on orbit are powered by Rocket Lab solar products.

According to the company, IMM Apex provides customers a high-efficiency, lightweight and germanium-free option that pairs proven reliability with faster production times, more cost-effectively powering ambitious missions without compromising performance.

IMM Apex is available now, with the company noting ongoing advancements to support future applications.