Which Japanese space probe entered orbit around Venus in 2015?

Akatsuki was the Japanese space probe that entered orbit around Venus in 2015. Operated by JAXA, it successfully reached an alternative elliptical Venusian orbit on 7 December 2015 after its original orbit-insertion attempt had failed five years earlier.

The probe launched in May 2010 as the Venus Climate Orbiter, also known as Planet-C. Its first attempt to enter Venus orbit failed when its main engine shut down too soon, leaving Akatsuki in orbit around the Sun. Engineers preserved the spacecraft and devised a recovery plan using its smaller attitude-control thrusters.

Akatsuki’s cameras observed Venus at ultraviolet, infrared, microwave, and other wavelengths. The mission studied the planet’s super-rotating atmosphere, cloud physics, atmospheric circulation, lightning, and possible volcanic activity. Its orbit was much more elongated than originally planned, but it still enabled important climate observations.

Nozomi was a Japanese Mars probe, Kaguya orbited the Moon, and Hayabusa visited an asteroid. Those missions are common mix-ups because all were important Japanese planetary spacecraft, but only Akatsuki entered Venus orbit.