The Fourier–Kelvin Stellar Interferometer (FKSI)—A practical infrared space interferometer on the path to the discovery and characterization of Earth-like planets around nearby stars

During the last few years, considerable effort has been directed towards large-scale (>$1 billion USD) missions to detect and characterize Earth-like planets around nearby stars, such as the Terrestrial Planet Finder Interferometer (TPF-I) and Darwin missions. However, technological issues such as formation flying, cryocooling, null depth for broadband signals, control of systematic noise sources, budgetary pressures, and shifting science priorities at NASA and ESA, will prevent these missions from entering Phase A until the middle of the next decade. A simplified nulling interferometer operating in the near- to mid-infrared (e.g. ∼3–8 microns), like the Fourier–Kelvin Stellar Interferometer (FKSI), can characterize the atmospheres of a large sample of the known planets. Many other scientific problems can be addressed with a system like FKSI, including the imaging of debris disks, active galactic nuclei, and low mass companions around nearby stars. We discuss the rationale, both scientific and technological, for a competed mission in the $450–600 million (USD) range, of which FKSI is an example. To cite this article: W.C. Danchi, B. Lopez, C. R. Physique 8 (2007).