High resolution (metric) SAR microsatellite, based on the CNES MYRIADE bus

A significant reduction of observation satellite size (and cost) has been achieved over the years. Have we reached the limit? How can we go further? Those questions are all the more relevant as one of the future challenges in spaceborne SAR is likely to be the near real time imaging (less than 30 or 60 minutes delay). not only in military but also in civilian studies, which automatically requires a large number of satellites in orbit. In SAR, unlike in the optical, the barriers cannot be only technological, there is a matter of the physics and of the wavelength which makes the SAR antenna area a tight constraint. Increasing the frequency beyond the X band is of poor benefit since it jeopardises the all weather capability of radar. CNES is exploring the capability of an SAR microsat based on the CNES bus product line currently in development and called MYRIADE (<120 kg satellite mass). The core mission objective is high resolution (1 or 2 meters) in the X band. Such resolution achievement under the limited mass and power budget requires significant trade-offs against other performance areas (swath, incidence domain. working duty cycle), however these operational limitations of each satellite can be circumvented by the high cost saving and the resulting affordability of a large constellation format. The current studies are aimed at identifying new SAR mission rationales that the micro-satellite concept may open. up and at identifying the technological constraints and development needs. The relevant technological areas are antennas (parabolic reflector or electronic reflect array, fixed or deployable), small TWTA, ultra-capacitor (to concentrate energy from battery into high power bursts for payload), low mass data handling and telemetry. This paper presents the status of the analyses and tradeoffs at the early phase of the study.