Akatsuki , also known as the Venus Climate Orbiter (VCO) and Planet-C, was a Japan Aerospace Exploration Agency (JAXA) space probe tasked with studying the atmosphere of Venus. It was launched aboard an H-IIA 202 rocket on 20 May 2010, but failed to enter orbit around Venus on 6 December 2010. After the craft orbited the Sun for five years, engineers successfully placed it into an alternate Venusian elliptic orbit on 7 December 2015 by firing its attitude control thrusters for 20 minutes, making it the first Japanese satellite to orbit Venus.