The ESA Scout NanoMagSat Mission, a Nanosatellite Constellation to Further Improve Geomagnetic Field and Ionospheric Environment Monitoring and Modeling, on Course for First Launch in 2027

Geomagnetic field and ionospheric environment LEO monitoring is presently achieved by the three polar orbiting, two side-by-side and one with relative local time (LT) drift, satellites of the Swarm Earth Explorer ESA constellation launched in November 2013, forming the backbone of a broader constellation now also including the Chinese CSES-1 and CSES-2 missions launched in February 2018 and June 2025, maintained 180° apart on the same Sun-Synchronous orbit, as well as the Chinese MSS-1 41° inclination mission, launched in May 2023. These are currently the only missions carrying an absolute magnetometry payload critical for global field monitoring.

Here, we will present the latest status of the NanoMagSat constellation mission, third small science mission selected for ESA’s new Earth Observation fast track Scout program that taps into New Space. Scout is a new framework (3 years for implementation, cost ≤ 35 M€) by which ESA aims to demonstrate disruptive sensing techniques or incremental science, while retaining the potential to be subsequently scaled up in larger missions or implemented in future ESA Earth Observation programs.

NanoMagSat will cover all LT at all latitudes, with special emphasis on latitudes between 60°N and 60°S, where all LT will be visited within about a month, much faster than is currently achieved. Each 16 U satellite will carry an advanced miniaturized absolute scalar and self-calibrated vector magnetometer with star trackers collocated on an ultra-stable optical bench at the tip of a 3m deployable boom, a compact High Frequency Magnetometer at mid-boom, a multi-Needle Langmuir Probe and dual frequency GNSS receivers on the satellite body. This payload suite will acquire high-precision/resolution oriented absolute vector magnetic data at 1 Hz, very low noise scalar and vector magnetic field data at 2 kHz, electron density data at 2 kHz, and electron temperature data at 1 Hz. GNSS receivers will also allow recovery of top-side TEC and ionospheric radio-occultation profiles. NanoMagSat will start deploying in 2027, with full constellation to be operated for a minimum of three years between 2028 and 2031.

Science objectives will be introduced and the rationale for the choice of the payload and constellation design explained. The planned data products, with their expected performance, will also be described. Special emphasis will be put on the innovative aspects of the mission with respect to previous missions. Finally, possibilities of further expanding the constellation though international collaboration as encouraged by IAGA resolution 2025 n°1 will be discussed.