The deployable ‘Wrapped Rib’ Cassegrain antenna is originally designed for Synthetic Aperture Radar (SAR) at X-band. It provides a way of bringing large aperture antenna (>3m) for SAR to a 100~kg small satellite, enabling persistent imaging in spotlight mode to deliver unparalleled resolutions through cloud and at night. 

The metal mesh, supported by composite ‘ribs’, forms a required parabolic reflector surface in the deployed configuration.

Deployability in both the primary reflector and secondary reflector enables an excellent stowage ratio, 6:1 radially and 3:1 axially. The antenna is easily accommodated to ESPA ring platforms. 

The antenna employs a simple deployment system using its own strain energy from the stowed configuration and is RF passive once deployed in orbit, simplifying the SAR radar electronics. 

TT&C and PDT (Payload Data Transmission) antennas can be accommodated on the back of the deployable mast, enabling consistant communications with ground stations without blockage by the reflector.

OSS has been significantly investing in the development of technologies and verification through extensive analysis and ground based test programmes, including a RF test campaign over 8 years.

The antenna successfully launched and deployed in orbit in January 2026 and is now TRL 9.