High Resolution, Wide Swath SAR Observation From DiskSat at VLEO

This paper proposes a novel concept of quasi-two-dimensional SAR (synthetic aperture radar) satellites, SAR DiskSats, featuring a deployable passive slot array antenna (De-PSAA) that can be compactly folded within the quasi-two-dimensional (Q-2D) satellite body. This Q-2D configuration allows for potential flexible solar cell sheets to be installed on the backside of the antenna, as the antennas do not dissipate heat. This satellite configuration is also suitable for stacking within a rocket fairing for the mega-constellation launch of SAR DiskSats into VLEO (very low Earth orbit). The proposed DiskSat's thin edge cross-section reduces aerodynamic drag, enabling the satellite to operate at VLEO, thereby taking advantage of improved short-range SNR. This advantage in RF power enhances ground resolution, wide swath with elevation frequency scan technique. It also makes it possible to have a small SAR DiskSat at VLEO. The paper describes a newly proposed corporate feed X-band Q-2D slot array antenna with a 1.2-GHz bandwidth for 0.25-m ground resolution. Additionally, the paper describes the joint US-Japan collaboration on a technology development and implementation roadmap for transitioning the proposed De-PSAA and conventional SAR payloads to pVLEO mega-constellations of HRWS-SAR DiskSats for commercial and civilian applications. The long-term goal is to achieve 0.25-m ground resolution (spotlight) and 1,000km swath width (stripmap).