Development of Solar-C_EUVST structural design

The Solar-C_EUVST is a mission designed to provide high-quality solar spectroscopic data covering a wide temperature range of the chromosphere to flaring corona. To fulfill a high throughput requirement, the instrument consists of only two optical components; a 28-cm primary mirror and a segmented toroidal grating which have high reflective coatings in EUV-UV range. We present a mission payload structural design which accommodates long focal length optical components and a launcher condition/launch environment (JAXA Epsilon). We also present a mechanical design of primary mirror assembly which enables slit-scan observations, an image stabilizing tip-tilt control, and a focus adjustment on orbit, together with an optomechanical design of the primary mirror and its supporting system which gives optically tolerant wavefront error against a large temperature increase due to an absorption of visible and IR lights.