Abstract: Thorough, population-level understanding of habitable and inhabited planets requires systematic studies of large samples of planets. However, the very slow growth of the light-collecting area of space telescopes and their very high costs remain severely limiting factors for exoplanet and biosignature studies. I will introduce the Nautilus Space Observatory concept that is designed to spectroscopically characterize the atmospheres of 1,000 exo-earth candidates. Nautilus is enabled by a revolution in the space launch industry and by a novel optical technology: Multi-order diffractive engineered material (MODE) lenses. MODE lenses provide ultralight and easier-to-fabricate alternatives to primary mirrors and, thus, enable a new paradigm for very large space telescopes. I will show our active UArizona-led technology development program, our latest MODE lens prototypes, supporting facilities, and progress on design, fabrication, alignment, and testing methods. I will describe the Nautilus Space Observatory and its science scope, and the exciting scientific opportunities such a mission will enable – far beyond exoplanet characterization.