Rocket Lab releases germanium-free 31.5%-efficient space solar cell

(SpaceEnergy) US launch and space-systems company Rocket Lab has released a germanium-free space solar cell with 31.5% beginning-of-life conversion efficiency and 40% lower cell mass.

The company said its Inverted Metamorphic (IMM) Apex cell removes the germanium substrate used in conventional multi-junction space solar cells, reducing exposure to rising costs and supply constraints for the critical mineral.

IMM Apex is designed as a mechanical and electrical drop-in replacement for heritage germanium-based cells, allowing spacecraft manufacturers to adopt it without major system retooling. Rocket Lab said the cell retains radiation hardness and performance across temperature ranges while providing higher specific power.

The company said manufacturing improvements and capital investment have enabled production at multi-100 kW volumes. IMM Apex is available to customers now.

Rocket Lab’s earlier IMM technology has powered satellites for more than a decade and was used on the National Aeronautics and Space Administration’s Ingenuity Mars helicopter. More than 1,100 satellites in orbit use Rocket Lab solar products, according to the company.