Stratospheric Aerosol and Gas Experiment (SAGE) from SAGE III on the ISS to a Free Flying SAGE IV Cubesat

The Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International SpaceStation (ISS) is widely accepted as a stable source for high-quality stratospheric ozone, aerosol, andwater vapor measurements since it was installed on the ISS in 2017. The ISS is a unique platform thatprovides access for hosted payloads while furnishing infrastructure for power, uplink, downlink, etc.for instrument operations. The opportunities, risks, and challenges from operating on the ISS aredescribed in addition to comprehensive lessons learned. In addition, SAGE IV is presented as anoption for the future of the SAGE lineage where the lessons learned from SAGE III and technologicaladvances have enabled the instrument to fit into a 6U CubeSat yielding a significantly smaller andcheaper form-factor to preserve the continuity of critical atmospheric measurements.