Imaging devices are essential components for a range of increasingly more complex and specific space missions. To serve these missions, CMOS image sensors (CIS) or detectors are now widely used due to their benefits, e.g. ease of manufacturing on industrial processes, performances, and high integration, and being real “Systems-on- Chips”. Detectors are listed as a priority by the European Commission for supporting the needs arising from EU space missions. Detectors are qualified as critical space technologies in the Technical Guidance Document for Horizon European Space Work Programme 2024. The specifications of detectors include many parameters, such as the resolution (number of pixels), format, sensitivity, and read-out speed.

On top of that, a major system factor of merit is the Signal Noise Ratio (SNR). The SNR is a direct function of the Full Well Capacity (FWC) and the noise readout level of the pixel. For most Earth observation and Space Situational Awareness (SSA) missions, the FWC should be at least of 40ke- to reach a SNR of about 100 for typical luminance (about 3 to 4 times less than the maximum luminance). To satisfy this requirement, large pixel (>5 μm for 2D arrays and >8 μm for linear/Time Delay Integration (TDI) arrays) pitch has been adopted, as it enables higher FWC.

Provided it does not degrade the optical instrument spatial resolution capability (i.e. keeping the pixel MTF high), reducing the pixel pitch is however desirable. It will enable an increase to the density of pixels within the focal plane, whilst minimizing the detectors’ production costs as well as some of its “non-ideality”, such as dark current and particularly post proton. Hence, to maintain affordable satellite costs while improving their observation efficiency (e.g. by increasing the number of pixels paving the focal plane), the space market’s demand for smaller pixel pitch with high FWC has emerged.

Abstract: The renewed interest in space exploration, surveillance, and security of space objects has created competitive conditions requiring support for start-ups and established companies via funding programs. However, if the space sector in EU countries doesn’t receive the necessary support in time, it will struggle to maintain competitiveness. The EU-funded TENSIS project will strengthen the know-how of space-based CIS and guarantee independence across the entire industrial chain. Consequently, strengthening the production chain through development, validation and manufacturing becomes vital. The chosen CMOS-180nm technology must be scalable to high image resolution, tolerant to cosmic radiation, cost-effective, customizable, and suited to space applications. The TENSIS project will boost European competitiveness, benefit prime contractors and equipment manufacturers, and strengthen EU's independence from foreign suppliers. ​