Int-Ball2: On-Orbit Demonstration of Autonomous Intravehicular Flight and Docking for Image Capturing and Recharging

This article presents the system architecture and the orbital demonstration results of the Int-Ball2, a free-flying camera robot developed by the Japan Aerospace Exploration Agency (JAXA). The purpose of the Int-Ball2 project is to assist astronauts and reduce their workload in the International Space Station (ISS). This robot is an upgrade from the first Int-Ball, enhancing the propulsion subsystem for greater maneuverability and adding a new docking station (DS) for autonomous battery recharging. This study performed comprehensive ground tests for autonomous maneuvering and docking, employing a combination of a fully software-based simulator, a hardware-in-the-loop (HIL) simulator, and a planar air-bearing facility. After a successful launch to the ISS, the Int-Ball2 demonstrated its ability to work in microgravity without relying on astronaut support. The results obtained from ground and orbital tests underscored the effectiveness of our system design and ground verification approach. Further, we present key technologies essential for the Int-Ball2’s successful implementation on board the ISS. We expect the insights from this project to be invaluable to future missions involving free-flying robots in microgravity.