MACE: Development of an Autonomous Solar Assisted Aircraft for Monitoring Volcanoes up to 30,000ft AMSL

Monitoring Aerosol Climate Engineering (MACE) is a UK project developing an autonomous uncrewed aerial system (UAS) for measuring aerosol and cloud microphysics in hazardous, highaltitude volcanic environments as natural analogues for Solar Radiation Management (SRM). Volcanic degassing and eruptive plumes provide real-world testbeds for injection, dispersion, chemical evolution, and radiative effects relevant to Stratospheric Aerosol Injection (SAI) and Marine Cloud Brightening (MCB). The project integrates a new high-altitude fixed-wing airframe with lightweight gas and particle instrumentation, and AI-enabled real-time plume interception and resampling to achieve 4D tracking up to 10 km AMSL. Field campaigns planned at Fuego (Guatemala), Soufrière Hills (Montserrat), and Lascar (Chile) will characterise aerosol formation, cloud responses, and radiative forcing across a range of altitudes, whilst establishing rapid-deployment readiness for future major eruptions. The MACE aircraft will be a modular, zero-emission monitoring platform for quantifying processes critical to SRM risk assessment, together with providing a rapid world-wide transportable volcanic response capability.