The Japan Aerospace Exploration Agency (JAXA) has begun a key mission to study the environmental conditions of the Venus planet. JAXA’s spacecraft, Akatsuki’s Ultraviolet Imager (UVI) will be equipped with e2v Charge Coupled Device (CCD) image sensors. These sensors will be launched on space to explore the Venus planet.
The e2v CCD47-20 sensors are frame transfer Charge Coupled Devices with 1024 x 1024 pixels, with each measuring 13µmsq. The sensor provides optimal performance in the 280-365nm wavelength range. The device is illuminated at the back and comes in a sealed, hermetic package. A sapphire window provides optimal transmission in the ultraviolet range.
Venus, also called Earth’s sister planet is similar to Earth in size, mass and gravity. However, both Earth and Venus have different climatic conditions. Compared to other terrestrial planets, Venus has an extremely dense atmosphere consisting mostly of CO2 and sulfuric-acid clouds. Studies indicate that years ago Venus had a similar atmosphere like that of Earth. It is also presumed that oceans had previously existed on the planet, but evaporated as a result of increased temperature, leading to dry deserts and atmospheric greenhouse gases. The spacecraft will explore the cause of these climatic conditions and will provide a better understanding about Earth’s evolution and its climatic conditions. It will also provide a detailed explanation about varied planetary environments existing in the solar system.
The spacecraft will utilize an infrared light to explore the planet. It is equipped with advanced instruments that will help examine the ground’s surface and atmospheric conditions of the Venus’s cloud layer. The spacecraft will enter an elliptical orbit, which is 300 to 80,000 km from the surface of Venus. The distance will enable the spacecraft to observe the planet’s atmospheric particles, storm winds, surface conditions and meteorological events. The spacecraft will also take close-up pictures of the planet.
The Ultraviolet Imager is specifically configured to determine the UV rays that get distributed from the cloud tops at an altitude of ~65km, centered at 283nm and 365nm wavelengths.
The planet’s atmosphere and its sulfuric-acid clouds indicate the absorption of solar radiation between 200-500nm and 200-320nm, respectively. Absorption above 320nm is attributed to another unidentified absorber. To determine the dynamics of its atmosphere, energy balance and the atmospheric chemistry, the UV absorbers need to be identified since they control the heating aspects of the atmosphere. The Ultraviolet Imager will determine the relationship of the UV absorbers with the wind field and the cloud structure. Cloud motion tracking will produce wind vectors at the cloud top. The layer above the main cloud and the scattering of cloud particles will be investigated with limb observations. At a field of view of 12o, the picture of the planet can be taken at a distance of less than 8.5 revolutions.
e2v’s Marketing and Applications Manager, Jon Kemp, informed that the CCD47-20 imaging sensors are used in a number of applications. He expressed his happiness on providing the sensor devices for JAXA’s mission and said that he is looking forward to working with them in the coming days.
e2v designs and distributes advanced electron components, sub-systems, cameras, semiconductors and CCD and CMOS sensors for the aerospace, defence, commercial, industrial, and science and medical sectors. The company has a number of manufacturing centers in North America and Europe, and has a network of sales and technical support centers as well as local resellers and distributors across the globe. e2v’s headquarters is based in UK.