Understanding the origin and evolution of galaxies, stars, planets and life itself are fundamental objectives of Astronomy. Although impressive advances have been made, our knowledge of how the first galaxies and stars formed, and how they evolve to into what we see around us today, is still far from complete. A major reason for this is that the birth and much of the growth of galaxies, stars and planets occurs in regions that are hidden by a thick blanket of dust – virtually inaccessible to the optical instruments that have been the tools of the trade since the invention of the telescope. A complete physical understanding of the processes that define our Universe is only possible with sensitive observations in the infrared which can penetrate dust and reveal the inner workings of galaxies, star forming regions, and planet forming systems, over much of cosmic history.
A joint European-Japanese project is proposed to implement SPICA, an infrared space observatory with a large, cryogenically cooled telescope designed to achieve for the first time truly background limited performance, for launch and operations at the end of the next decade. With a 2.5-meter primary mirror actively cooled to below 8K, combined with a new generation of ultra-sensitive detectors, SPICA will offer the community a unique astronomical facility, able to cover the spectral range from 12 to 230 µm to unprecedented depths of a few 10-20 W/m2 for spectroscopy (5σ) in 1 hour. This represents a gain in sensitivity of more than two orders of magnitude over both Spitzer and Herschel, a gigantic leap in capabilities for exploring the Universe. Given its enormous leap in sensitivity and spectroscopic capabilities, SPICA commands an enormous discovery space which will enable scientists to react quickly to new discoveries with ALMA, JWST and ELT’s by exploring a unique spectral range.