Design and Development of an All-Sky Electrostatic Analyzer

The All-Sky Electrostatic Analyzer (A-ESA) is a scientific payload designed for installation on a lunar rover, which will observe variations of the plasma environment on the Moon. Since the launch of the science payload project, the team from National Cheng Kung University (NCKU) have successfully completed the PDR, CDR, TRR, and PAR reviews. By the end of 2024, the team from NCKU delivered the A-ESA to the Taiwan Space Agency (TASA). In early 2025, the A-ESA was sent to the Lunar Outpost for integration testing. A-ESA consists of an electrostatic analyzer on top, while an MCP assembly, power supply units, and electronics are located underneath. A-ESA features entrance scanning deflectors and inner scanning deflectors. The entrance of A-ESA is electrically scanned within approximately 90° in the vertical direction, resulting in a hemispherical field of view (FOV). When A-ESA operates in observation mode, it divides the collection of scientific data into 8 sections horizontally and 6 sections vertically. By sweeping high voltage, it generates 16 different energy levels. As a result, A-ESA can measure the plasma distribution function and the energy of charged particles in a hemispherical space on the lunar surface.