A conceptual design of a wide-field near UV transient survey in a 6U CubeSat is presented. Ultraviolet is one of the frontier in the transient astronomy. To open up the discovery space, we are developing a 6U CubeSat for transient exploration. The possible targets will be supernova shock-breakouts, tidal disruption events, and the blue emission from NS-NS mergers in very early phase. If we only focused on nearby/bright sources, the required detection limit is around 20 mag (AB). To avoid the background and optical light, we chose a waveband of 230−280 nm. As an imaging detector, we employ a delta-doped back-illuminated CMOS. In addition to delta doping, the multi-layer coating directly deposited on the detector enables both a high in-band UV QE and the ultra-low optical rejection ratio. Taking into account these specifications, even an 8 cm telescope can achieve the detection limit of 20 mag AB for a FoV larger than 60 deg 2. We also designed the satellite bus system for this mission by utilizing commercially available cubesat components satisfying the mission requirements.

This study presents in-orbit demonstrations of a deep learning attitude sensor (DLAS) aboard the Japan Aerospace Exploration Agency (JAXA) small-satellite, Rapid Innovative Payload Demonstration Satellite 1. The DLAS is a spaceborne component that consists of star trackers, Earth cameras, and onboard computers. We propose a novel attitude determination method that uses a small camera and image recognition algorithm on board the DLAS to achieve three-axis attitude determination with minimal weight and volume. The DLAS mission further includes a demonstration of a low-cost high-performance star tracker that integrates consumer products. The development of the DLAS began in 2016 when it was adopted as the theme of the JAXA Innovative Satellite Technology Demonstration program. It was launched into a sun-synchronous orbit at an altitude of 500 km in January 2019 for approximately one year. This paper describes the results obtained from the DLAS operation and its future applications. The DLAS demonstrated an Earth camera image identification accuracy of more than 70%. Moreover, the obtained attitude determination accuracy was approximately 2.8 deg for the Earth camera and approximately 14 arcs for the star trackers. The technologies developed in the DLAS have been implemented in a subsequent microsatellite (HIBARI) of the Tokyo Institute of Technology.