Rydberg Receivers for Space Applications
Rydberg-atom sensors convert radiofrequency, microwave and terahertz fields into optical signals with SI-traceable calibration, high sensitivity, and broad tunability. This review assesses their potential for space applications by comparing five general architectures (Autler-Townes, AC-Stark, superheterodyne, radiofrequency-to-optical conversion, and fluorescence) against space application needs. We identify promising roles in radiometry, radar, terahertz sensing, and in-orbit calibration, and outline key limitations, including shot noise, sparse terahertz transitions, and currently large Size, Weight, Power and Cost. A staged roadmap highlights which uncertainties should be resolved first and how research organisations, industry and space agencies could take the lead for the different aspects.