spaceSpace and Physics

We're About To Learn A Whole Lot More About Venus Thanks To Japan's Akatsuki Mission


Jonathan O'Callaghan

Senior Staff Writer

1090 We're About To Learn A Whole Lot More About Venus Thanks To Japan's Akatsuki Mission
Akatsuki is now in orbit around Venus. JAXA

It may be five years behind schedule, but Japan’s Akatsuki spacecraft is finally starting its scientific mission around Venus – and it has already returned some rather stunning images in the process.

Akatsuki originally launched in May 2010, and was expected to enter orbit around Venus later that year. But a problem with its main engine en-route to the second (and hottest) planet of the Solar System saw it enter orbit around the Sun instead. The team was able to salvage the mission with its secondary thrusters, but it meant an agonizing wait of five years as the spacecraft slowly swung around to enter orbit again in December 2015.


At the International Venus Conference in Oxford, U.K., last week, the Japanese space agency’s (JAXA) Akatsuki project manager, Masato Nakamura, presented the first results from the little probe that could, reports Nature. He also revealed that most of the probe’s instruments are in fine health, save for one camera that seems to have degraded during the unintended mission extension.

He showed off one fascinating image that revealed streaked clouds in the atmosphere of Venus. In the image, which is on the left below, definition between the different layers of the Venusian atmosphere can clearly be seen. It’s hoped that Akatsuki could help reveal how the acidic clouds of Venus are replenished with sulfur dioxide.

A second image, on the right below, was shot by an infrared camera on the spacecraft. It shows a moving cloud formation on Venus, shaped like a bow. Interestingly, this cloud formation moved from pole to pole for several days, but appeared to be more influenced by the rotation of Venus than the fast-moving atmosphere, something that has intrigued scientists.

Above, two images of Venus returned by Akatsuki. ISAS/JAXA


“How a band structure can run from north to south is a puzzle,” Takeshi Imamura, project scientist on the Akatsuki mission, said in a JAXA interview. “We never imagined that we would see this kind of thing.”

At the moment, Akatsuki is just taking still images of Venus, but the team plans to start recording video this month, which will be the first-ever recordings of atmospheric cloud movement on Venus. “I think after that our understanding will progress in leaps and bounds,” added Imamura.

One issue with the Akatsuki spacecraft, though, is that it is not in the originally intended orbit when the mission launched in 2010, owing to the engine malfunction. It was originally planned to orbit every 30 hours, moving between 300 and 80,000 kilometers (190 and 50,000 miles) from the surface. Its new orbit, though, will take 10.5 days, moving between 4,000 and 370,000 kilometers (2,500 and 230,000 miles).

This will mean the images it returns are lower resolution than planned, so spotting particular features like lightning might be more difficult. But the large sweeping orbit, five times further than intended, will allow more images of the entire planet to be taken, allowing the team to monitor large-scale changes on the planet.


Nonetheless, the scientists behind the mission are no doubt thrilled that Akatsuki’s science mission is up and running. Data gathered by the spacecraft will be exclusively available to JAXA scientists in the first year after it is acquired, but planetary scientists around the world will be eagerly awaiting results from the mission to help give us a better understanding of this fascinating world.

And with more missions to explore Venus in the works, including two NASA proposals, Akatsuki may renew excitement in a planet that has been devoid of any orbiting spacecraft since Europe's Venus Express mission ended in December 2014.


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