Japan's Venus Orbiter
Akatsuki, meaning 'dawn', was JAXA's Venus Climate Orbiter. Its main engine failed during its first attempt to enter orbit in December 2010, leaving it circling the Sun. Five years later engineers used its small attitude thrusters to put it into orbit around Venus in December 2015, making it Japan's first spacecraft to orbit another planet.
Studying Venus's Extreme Weather
Five cameras, from ultraviolet to thermal infrared, tracked an atmosphere that races around the planet about 60 times faster than Venus itself turns. Akatsuki found a giant bow-shaped wave in the clouds about 10,000 km long that stayed above the same highlands, and a fast equatorial jet in the cloud layers, changing how scientists model the weather on rocky planets.
Silence at Venus
JAXA lost contact with Akatsuki in April 2024 after an attitude-control problem left it unable to point its antenna at Earth. After more than a year of failed recovery attempts, the agency formally ended the mission on 18 September 2025, leaving Venus with no working orbiter.