The Z4J from Rocket Lab is a 4-Junction Satellite Solar Cell on a germanium substrate specifically that is designed for GEO orbits. It is fabricated using a germanium substrate and has 30 % efficiency at maximum power point. This space-qualified solar cell requires a DC supply of 3.54 V and has a power consumption of 4 MW. It is compatible with corner-mounted silicon bypass diode for individual cell reverse bias protection, weldable or solderable contacts, and mechanical strength for reduced attrition during assembly and lay down. This solar cell is fully tested to the AIAA-S111-2014 space qualification and characterization standards.
