A Japanese Aerospace Exploration Agency (JAXA) spacecraft designed to monitor volcanic activity on Venus as well as information on its clouds and climate using multi-wavelength imaging. JAXA launched the probe together with IKAROS on 21 May 2010 from the Tanegashima Space Centre aboard an H-IIA rocket. The 320-kg craft has a payload including an ultraviolet imager, longwave infrared camera, two microwave cameras, lightning and airglow camera, and a radio science experiment. Akatsuki (‘Dawn’ in Japanese) reached Venus on 6 December 2010, but a main-engine failure prevented it from entering a proper orbit. The £190m mission had to wait in solar orbit five years to the day before it fired its small altitude control thrusters to achieve a successful highly elliptical orbit around the planet. A few days later, the spacecraft imaged a planet-wide bow-shaped atmospheric gravity wave that may be the largest such feature in the Solar System. The orbiter started its two-year period of ‘regular’ science operations in mid-May 2016. As of March 2017, two of its micron-wavelength cameras are no longer functioning.

An artist’s rendering of the Akatsuki spacecraft over Venus.

Credit: JAXA