Development of a very small high-performance image acquisition system for asteroid exploration rover MINERVA-I12

Hayabusa-2 is a new C-type asteroid exploration mission scheduled for launch with the aim of arriving at Asteroid 1999-JU3. The asteroid could provide valuable information regarding the origin and evolution of the solar system as well as the development of life on Earth and elsewhere. In addition to the mission to sample and bring back asteroid surface materials, Hayabusa-2 will deploy MINERVA-II2, a tiny hopping rover. MINERVA- 112 can potentially perform wide-range exploration to acquire various data on the asteroid surface. In particular, for detailed asteroid surface exploration, in-situ image acquisition is essential to survey the surface conditions because the shape, size, and components of the surface materials are not clear. However, the touchdown positions of Hayabusa-2 are limited. We are therefore planning an image acquisition mission to visually survey the asteroid surface conditions. We expect to obtain data on the color and shape of the rock, sand, or floating dust on the asteroid surface. We have developed a very small high-performance image acquisition system for MINERVA-II2 using commercial off-the-shelf technologies. The camera only weighs 40 g and is considered as the smallest space camera. In addition, the camera can capture images at megapixel resolutions. However, precisely predicting the imaging conditions is difficult because the asteroid surface conditions are still ambiguous. Moreover, remotely operating the image acquisition systems in real-time is difficult because the communication bandwidth is limited. To solve these problems, we need to implement robust autonomous control software for the image acquisition system to adapt to uncertain conditions. To implement this software, we first need to determine the possible asteroid surface conditions. We designed experiments to determine the image acquisition conditions by simulating the asteroid surface environment. From these experiments, we successfully implemented robust and autonomous control software that will reliably acquire images of the asteroid surface. This paper presents the miniature image acquisition system for the asteroid exploration mission. The results of the image acquisition experiments for a simulated asteroid surface environment and the control software are also introduced.