The Optical Design of the Sardinia Deep Space Antenna for Telemetry, Tracking, and Command

Commissioned in 2017 by the Italian Space Agency (ASI), the Sardinia Deep Space Antenna (SDSA) is currently able to operate in the X-band, supporting deep space and near Earth telemetry missions and scientific experiments. While sharing its infrastructure with the Sardinia Radio Telescope (SRT), the SDSA boasts its own dedicated control center and specific equipment. This paper outlines a new optical design and the radio frequency upgrades to enhance the SDSA’s capabilities for current and future tracking of deep space and near Earth missions. The proposed design aims to establish the SDSA as a state-of-the-art antenna in the field of space activities by capitalizing on its exceptional versatility. This includes its ability to accommodate new equipment and leverage the inherent characteristics of the SRT antenna, such as its active surface and frequency agility. A collaborative effort with ESA has resulted in a newly designed optical configuration enabling reception and transmission in the X, K, and Ka frequency bands. Specifically, the X and K frequency bands are allocated to near Earth radio communication (within a 2 million kilometer range). Additionally, the X- and Ka- bands configurations are designed for deep space operations, including the well-known triple-link technique for radio science missions beyond 2 million kilometers. To characterize the performance of the upgraded antenna, we present the electromagnetic simulations of the new optical design. We analyze the antenna radiation pattern across various downlink and uplink frequency bands and evaluate key parameters like gain-to-noise system temperature ( $G/T_{sys}$ ) and effective isotropic radiated power (EIRP). The simulations were conducted using the dedicated commercial software GRASP and CHAMP 3D by TICRA. The results of this study provide valuable information on the capability of the upgraded SDSA to enable a wide range of space communication and space science applications, making the SRT in its SDSA configuration one of the most equipped and technologically advanced ground segment facility.