One of the five cameras aboard the Venus Climate Orbiter “PLANET-C” is the “IR2,” whose observation target is infrared rays that are about two micron in wavelength. It aims to measure the high-temperature atmosphere of Venus under thick clouds, its movement, and distribution of its trace components. In other words, the IR2 is a camera that can see through the real surface of Venus. The IR2 is made of materials suitable for infrared ray observations (manufactured by Nikon) and its photo-taking device (element) which is equivalent to a CCD in a digital camera is made of Platinum Silicide (PtSi) element (manufactured by Mitsubishi Electric.)
The PtSi element is one million pixels (1024 x 1024). We are very proud of its high performance, which is far superior to commercially sold digital cameras or video cameras. It can work stably in the harsh environment of space with an excellent ability to capture both dark and bright objects (dynamic range) and a very high accuracy of measurement (linearity.) Currently, one million pixels is the highest level for this type of camera.
The PtSi detector shown in the photo is a trial piece. The one million pixel (1024 x 1024) light receiving surface is about 17 mm x 17 mm in size and attached to the IC package. We have already acquired satisfactory results for this element through a cooling evaluation test. In May 2006, we began to manufacture the prototype and flight model elements by slightly modifying the design of the trial piece.
The “IR2” and the other onboard infrared camera, “IR1,” are the main cameras of the orbiter. Although the two cameras target different observation wavelength ranges, their elements are almost the same. In addition to the lenses and elements, the camera unit itself, equipped with a cooling device for both the IR1 and the IR2, is developed by a Japanese precision equipment manufacturer (Sumitomo Heavy Industries, Ltd.) thus they are being developed 100% domestically.
It is not easy for Japan to challenge the space development field by itself, as Japan lags behind Western countries. Still, we believe that we can accumulate knowledge through the challenge to sophisticate our own advanced technologies and promote our cutting-edge space science. Therefore both the engineers and scientists are working together for this development.
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