Japan has quietly closed the book on its Akatsuki probe, which spent more time around Venus than anyone originally expected. The Japan Aerospace Exploration Agency confirmed that termination procedures began on September 18, 2025, after efforts to restore contact failed. By that time, the spacecraft had already far exceeded its planned lifespan. Akatsuki, launched in 2010, succeeded as Japan’s first extraterrestrial planet explorer, despite its uneven orbit. For years, it continued to send images and measurements from difficult and distant orbits. When communications ceased in 2024, the mission was already in its final stages. The decision to end operations came after months of silence, aging systems and limited options. What remains is a long observation record and a mission that lasted beyond many expectations.
Japan ends Akatsuki operations after a year of efforts to restore lost communications
Akatsuki departed from Earth in May 2010 aboard an H-IIA rocket from the Tanegashima Space Center. A first attempt to enter Venus’ orbit later that year failed, and the spacecraft instead orbited the sun. For some missions, that might have been the end of it. Akatsuki drifted for years while the engineers sought other opportunities. In December 2015, it finally slipped into a wide orbit around Venus. The trajectory wasn’t what I had originally planned, but it was good enough. From there, the spacecraft began steady work.
Observe the cloud, not the surface
Unlike many planetary missions, dawn It wasn’t focused on mapping the ground. Anyway, Venus’s surface is hidden by a thick layer of clouds. Spacecraft were created to monitor the atmosphere instead. Its cameras and sensors tracked cloud movement, temperature changes, and subtle changes in light and heat. Over time, a pattern began to emerge. Some were expected, some were not. The data showed how fast Venus’ atmosphere moves and hurtles around the planet in ways that remain difficult to explain simply.
Unexpected features appear in a hostile sky
Among Akatsuki’s more shocking discoveries were giant standing gravitational waves spreading through Venus’ atmosphere. It was larger than anything ever seen on any other planet. The spacecraft also helped reveal how Venus maintains its extreme hyperrotation with wind speeds far exceeding its rotation. Although these observations did not answer all questions, they added weight to long-standing theories and raised new ones. Venus, already known as harsh and unfamiliar, seemed even more complex.
Earth science tools used elsewhere
Some of Akatsuki’s work draws quietly from Earth-based research. Scientists have applied data assimilation techniques commonly used in Earth’s weather forecasting to Venus for the first time. Although this process was not perfect, it allowed us to align the model and observations more closely. As a result, although still incomplete, we now have a clearer picture of how Venus’ atmosphere behaves over time.
Silence at the end of a long run
In April 2024, communications with Akatsuki stopped when the accuracy of attitude control was decreasing. Recovery attempts continued, but no calls were returned. By that stage, the spacecraft had been in service for more than a decade and was well past its design life. Fuel was limited. The system was old. The decision to end the mission was shaped by reality rather than failure and was made without any drama.
What the dawn left behind
Akatsuki orbited Venus every 10.8 days, traveling between about 1,000 and 370,000 kilometers from Venus. Over eight years of observations, it steadily gathered data on one of the solar system’s most difficult worlds. Venus is still roughly the same size as Earth, but its climate is completely different. Akatsuki didn’t explain everything, but it closed the gap. For Japan’s space program, it marks an early setback, a slow recovery, and then an important long-running mission.