To observe the global ionosphere-thermosphere, CERMIT will use a constellation of nanosats. This requires innovative solutions for the satellite platform and for payload miniaturisation. CERMIT will use the Spire 6U platform which includes a star tracker to provide attitude information for thermospheric wind and magnetic field measurements and an inter-satellite communications link to meet the data latency requirements. The payload mix may comprise: - Spire’s STRATOS GNSS receiver (TRL9). Provides radio occultation (RO) data to determine the ionospheric electron density. Further, STRATOS precise orbits contribute to estimates of the thermospheric neutral density. - In-situ electron density sensor (TRL9). Langmuir probe or RF impedance sensor to measure the electron density. - MEMS accelerometers (TRL3). 3 axis accelerometer for thermospheric density and wind estimates. - Atomic oxygen sensor (TRL7-9). Either a dedicated instrument, possibly based on the FIPEX/APOLLON system or a mass spectrometer. - Magnetometers (TRL9). Magnetic field measurements, and detection of Auroral currents. The use of a large constellation of nanosats in CERMIT means that redundancy in the system is provided at the constellation level rather than at the satellite level. The risk to individual satellites can be further reduced by using Spire’s platform with a high level of flight heritage. Nanosats also provide a route to refreshing the constellation and payloads so that continuity of measurements can be maintained whilst taking advantage of technology enhancements. The use of 6U satellites means the system overall can be deployed rapidly and cost effectively. CERMIT will be a commercial Space Weather Service (SpWxaaS), building on Spire’s proven model for operational RO data as a service that is currently provided to meteorological customers (EUMETSAT, NOAA). ESA would act as the anchor customer, realising major efficiency savings over a traditional approach.
