Abstract Microprobes can be used as research tools allowing dedicated measurements in regions near planets or moons usually not accessible for orbiting spacecraft. Here, we mainly discuss the investigation of the near environment of Jupiter's Galilean moon Io. Of special interest are the composition and density distribution of Io's atmosphere, also Io's mass properties and the configuration of the current system in the Jupiter-Io magnetospheric environment. It is proposed to release the microprobe ca. one month before its arrival at Io from an interplanetary spacecraft (for example Pluto-Kuiper Express) near the begin of the gravitational swing-by manoeuver. The microprobe will be fully active and will transmit telemetry data to Pluto-Kuiper Express during the last twenty minutes before it performs a hard landing on Io's surface or a grazing fly-by. The proposed scientific model payload consists of a neutral gas spectrometer a 3 axis magnetometer sensor and a radio science instrument, the mass allocated to the Io probe will be kept extremely low, not exceeding 17 kg. The probe will be powered by both primary batteries and solar cells, it will be spin stabilized and actively controlled by a cold gas system, its thermal control will be accomplished by passive means and radioactive heater units (RHU's). We discuss in this paper the separation strategy from the main spacecraft, the design of an ultralight structure, the thermal control concept, the attitude control concept and the onboard electronics which has to operate in the extreme harsh radiation environment of Jupiter magnetosphere. The proposed microprobe concept offers enough flexibility to equip the probe also with different payloads. We discuss the possibility to perform measurements made by mass spectrometer and surface penetration radar instruments in the near environment of Jupiter's moon Europa.