Overview

The Venus probe “Akatsuki” is a Japanese spacecraft designed to observe the atmosphere and weather phenomena of Venus in detail. The mission’s goal is to investigate the atmospheric dynamics, cloud structures, lightning activity, and surface environment of Venus, thereby deepening our understanding of Earth’s meteorology. The spacecraft was launched on May 21, 2010, but the initial attempt to enter Venus orbit on December 7, 2010, failed. After five years of orbital adjustments, Akatsuki successfully entered Venus orbit on December 7, 2015. The mission is led by the Japan Aerospace Exploration Agency (JAXA).

“Akatsuki” measures 1.45 meters in length, 1.04 meters in width, and weighs approximately 517 kilograms. It orbits Venus in a polar orbit (with a periapsis of 400 km and an apoapsis of approximately 44,000 km) and conducts observations primarily in ultraviolet, near-infrared, and mid-infrared wavelengths.

Observation Instruments

UVI (Ultraviolet Imager)

UVI is a camera designed to observe the cloud structures of Venus in ultraviolet light, particularly in the 365nm and 283nm bands. By analyzing the fine structures and photochemical processes of the clouds in ultraviolet light, it can clarify the dynamics of Venus’s atmosphere and the movement of the stratosphere.

LIR (Longwave Infrared Camera)

LIR captures the movement of Venus’s clouds based on temperature differences using mid-infrared light (10μm band). This camera is crucial for understanding the formation processes of convective movements and large vortex structures by capturing the temperature distribution at the cloud tops.

LAC (Lightning and Airglow Camera)

LAC is a camera for observing lightning activity and airglow phenomena in Venus’s atmosphere. With the ability to detect light across a wide range of wavelengths, it can observe the frequency and intensity of lightning, as well as the airglow caused by lightning discharges in detail.

IR1 (1μm Camera)

IR1 observes the surface and lower atmosphere of Venus in near-infrared wavelengths (0.90μm to 1.01μm band). This allows for the analysis of surface temperatures, mineral distributions, and the dynamics of low-altitude clouds.

IR2 (2μm Camera)

IR2 observes Venus’s middle atmosphere and infrared wavelengths. It is tuned to near-infrared wavelengths (1.65μm to 2.32μm band) to investigate changes in the concentrations of water vapor and carbon dioxide. This advances our understanding of Venus’s climate changes and cloud formation mechanisms.

Achievements

Since starting observations in 2015, “Akatsuki” has collected detailed data on Venus’s atmosphere. Notably, it has provided insights into the mechanism behind the super-rotation of Venus’s atmosphere (the strong winds at the cloud tops). Additionally, it has been confirmed that lightning activity on Venus differs from that on Earth, providing new knowledge in atmospheric chemistry.

The initial failure to enter Venus orbit and the subsequent recovery process symbolize the challenges and triumphs of space exploration. Overcoming the technical issues and ultimately achieving mission success holds significant importance.