Japan ends the Akatsuki mission after a decade of tracking Venus’s turbulent skies |

Japan ends the Akatsuki mission after a decade of tracking Venus’s turbulent skies (AI-generated)

Japan has quietly closed the book on Akatsuki, a spacecraft that spent more time around Venus than anyone first expected. The Japan Aerospace Exploration Agency confirmed that termination procedures began on September 18, 2025, after efforts to regain contact failed. By then, the probe had already gone far beyond its intended lifespan. Launched in 2010, Akatsuki became Japan’s first successful planetary orbiter beyond Earth, even though its path there was uneven. For years, it continued sending back images and measurements from a difficult, distant orbit. When communication stopped in 2024, the mission was already deep into its final phase. The decision to end operations followed months of silence, ageing systems, and limited options. What remains is a long record of observation and a mission that outlasted many expectations.

Japan closes operations on Akatsuki after a year of trying to revive the lost communication

Akatsuki left Earth aboard an H-IIA rocket from Tanegashima Space Center in May 2010. Its first attempt to enter Venus’s orbit later that year failed, leaving the spacecraft circling the Sun instead. For some missions, that would have been the end. Akatsuki drifted for years while engineers searched for another chance. In December 2015, it finally slipped into a wide, looping orbit around Venus. The orbit was not what was first planned, but it was enough. From there, the spacecraft settled into steady work.

Watching clouds rather than surfaces

Unlike many planetary missions, Akatsuki was not focused on mapping the ground. Venus hides its surface behind thick cloud layers anyway. The spacecraft was built to watch the atmosphere instead. Its cameras and sensors tracked cloud motion, temperature shifts, and subtle changes in light and heat. Over time, patterns emerged. Some were expected, others less so. The data showed just how fast Venus’s atmosphere moves, racing around the planet in a way that still challenges simple explanation.

Unexpected features in a hostile sky

Among Akatsuki’s more striking findings was a massive stationary gravity wave stretching across Venus’s atmosphere. It was larger than anything seen before on another planet. The spacecraft also helped clarify how Venus maintains its extreme superrotation, with winds far outpacing the planet’s own spin. These observations did not solve every question, but they added weight to long-standing theories and raised new ones. Venus, already known as harsh and unfamiliar, appeared even more complex.

Earth science tools used somewhere else

Some of Akatsuki’s work drew quietly from Earth based research. Scientists applied data assimilation techniques, commonly used in weather forecasting on Earth, to Venus for the first time. The process was not perfect, but it allowed models and observations to sit alongside each other more closely. The result was a clearer, if still incomplete, picture of how Venus’s atmosphere behaves over time.

Silence at the end of a long run

In April 2024, communication with Akatsuki stopped during a period of lower precision attitude control. Recovery attempts followed, but contact never returned. By that stage, the spacecraft had been operating for more than a decade, well past its design life. Fuel was limited. Systems were old. The decision to end the mission came without drama, shaped more by reality than by failure.

What Akatsuki leaves behind

Akatsuki orbited Venus every 10.8 days, moving between about 1,000 and 370,000 kilometres from the planet. Over eight years of observation, it gathered a steady stream of data on one of the Solar System’s most difficult worlds. Venus remains Earth’s near twin in size, yet utterly different in climate. Akatsuki did not explain everything, but it narrowed the gaps. For Japan’s space programme, it stands as a mission that faltered early, recovered slowly, and then kept going long enough to matter.