This proposal will significantly advance Power Added Efficiency (PAE) beyond present-day state-of-the-art SSPAs operating at S-Band in the over 1kW peak output power regime, achieving a TRL 3-4 S-band/ 3.2 GHz solid-state power amplifier (SSPA) module. The greatly enhanced PAE will result in an SSPA with a compact form factor suitable for CubeSat/SmallSat or other NASA remote sensing platforms. The project aims to achieve over 1kW of output power, 50dB of Gain, PAE of no less than 60% and possibly greater than 75% through Recon-RFs advanced power amplifier design techniques based on next-generation waveform design capabilities and practices. Potential NASA Applications (Limit 1500 characters, approximately 150 words): The proposed S-Band SSPA module capable of PAE >60% will enhance NASAs remote sensing for SWaP-C conscious applications such as: SAR/InSAR Payloads for studying surface topology on Earth and on other planets Follow-on Missions to NISARs InSAR S-Band Geo-Physical Remote Sensing Payload VenSAR S-Band SAR payload for Geo-Physical Remote Sensing of Venus Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): Non-NASA commercial and DOD applications stand to benefit from Recon-RFs advancements in S-Band SSPA technology, such as: Airport Surveillance Radar Surface Ship Radar S-Band Satellite Communications S-Band Weather Radar Rural Broadband Back-Hauls Commercial InSAR/SAR for remote sensing of vegetation and geo-physical phenomena Duration: 6