Otto Hasekamp (PhD 2002) is senior scientist in the Earth Science Group of Space Research Organization Netherlands (SRON). He is specialized in remote sensing of aerosols, clouds, and atmospheric trace gases. He has led / is leading the development of retrieval algorithms for retrieval of aerosol properties from polarimetric measurements (PARASOL, SPEXone/PACE), retrieval algorithms of Greenhouse Gas concentrations (GOSAT, OCO-2, TROPOMI, CO2M), and several projects on the use of aerosol and cloud data to quantify the effects of aerosol on climate and on data assimilation of aerosols. He is Principal Investigator (PI) for the SPEXone instrument on the NASA PACE mission, launched February 2024. In this role, he is leading the development of the full data processing and is responsible for overall instrument performance, in-flight calibration and scientific output.