Focal plane instruments onboard SPICA

The SPICA, Japanese next generation infrared space telescope with a cooled 3.5 m primary mirror, will be a quite unique observatory in the mid and far-infrared with unprecedented sensitivity and the spatial resolving power. Here we briefly describe the key scientific objectives which can be performed only with SPICA, based on its unique design concepts. We then describe the scientific requirements for the focal plane instruments, and summarize the constraints on the various resources available for the focal plane instruments, derived from the spacecraft system design. We also outline the concept of the planned focal plane instruments, and the future development plan. Within the focal-plane instrument space (2.5m diameter, 0.5m height), two major instruments are so far planned to be equipped: one is a mid-infrared instrument, consisting of a mid-infrared camera, mid-infrared spectrometers, and a midinfrared coronagraph, while the another is a far-infrared camera and spectrometer. The mid-infrared camera will consist of four channels covering 5-38 μm with approximately 25-40 square arcminutes, while the mid-infrared spectrometer will have high-dispersion (R=30000) channels at 4-18 μm and moderate-dispersion (R=3000) channels at 16-38 μm. The mid-infrared coronagraph will have both imaging and spectroscopic capability at 5-27 μm, with the contrast higher than 10-6. As for the far-infrared camera and spectrometer, a Fourier-type imaging spectrometer covering 30-210 μm is proposed and extensively studied by the European consortium (SAFARI consortium). A far-infrared and sub-millimeter grating spectrometer instrument is also under consideration by the US SPICA team.