This paper gives details of the development and verification of an engineering model of an external secondary payload unit for multi-point time resolved measurement of atomic and/or molecular oxygen as a key parameter of the lower thermosphere. The atomic and/or molecular oxygen measurement is based on solid oxide electrolyte micro-sensors which operate at an elevated temperature of 600-700C, heated by an electrical resistance. The science unit named APOLLON (Atmospheric Portray of Oxygen Level with Low Orbit Network) consisting of the micro-sensor itself, the necessary electronic I/F circuitry, harness and the mechanical platform/housing and can be placed on a satellite platform in free flow. The actual flux required for an accurate measurement will be obtained from the attitude of the satellite with respect to its direction of motion. Details of the technology, the design and the verification tests of the science unit APOLLON will be presented as well as potential applications and an outlook of future work.