The ESA Darwin mission is primarily devoted to the detection of earth-like exoplanets and the spectroscopic characterization of their atmospheres for key tracers of life. Darwin is implemented as a free-flying stellar interferometer operating in the 6.5-20 micron wavelength range, and passively cooled to 40 K. The stellar flux is suppressed by destructive interference (nulling) over the full optical bandwidth. The planetary signal is extracted from the zodiacal background signature by modulating the optical response of the interferometer. The Darwin mission concept has evolved considerably in the past years. The original concept, based on six 1.5 m telescopes, has been replaced by more efficient designs using three to four three-meter class apertures. A novel 3D architecture is being evaluated, together with the conventional planar one, bearing the potential for significant volume and mass savings and enhanced straylight rejection. A number of technology development activities have been successfully completed, including optical metrology, optical delay lines, and single-mode infrared optical fibers. A second iteration of the Darwin System Assessment Study has been kicked off end 2005, aiming to consolidate the overall mission architecture and the preliminary design of the Darwin mission concept. This paper illustrates the current status of the Darwin mission, with special emphasis on the optical configuration and the technology development programme in the area of optics.
SPICA (SPace Infrared telescope for Cosmology and Astrophysics) was selected for study as a mission of opportunity within the science programme Cosmic Vision 2015-2025 of the European Space Agency, with a planned launch in 2017. Observing in the 5 - 210 micron waveband, one of its major goals is the discovery of the origins of planets and galaxies. ESA's contribution is the provision of the SPICA Telescope Assembly (STA) featuring a 3.5 m primary mirror cooled to < 5K, and instrument engineering and management of a nationally funded European FIR instrument (SAFARI) as part of SPICA's payload. SAFARI is an imaging spectrometer operating at 30 - 210 micron, baselined as a Mach-Zehnder (MZ) Fourier Transform Spectrometer (FTS). An internal ESA study has been carried out to address the specific challenges
associated in particular with STA and SAFARI, taking into account resource margins and interface specifications driven by the overall spacecraft design. This paper provides a summary of the preliminary results achieved during this study.
The Japanese led Space Infrared telescope for Cosmology and Astrophysics (SPICA) will observe the universe over the
5 to 210 micron band with unprecedented sensitivity owing to its cold (~5 K) 3.5m telescope. The scientific case for a
European involvement in the SPICA mission has been accepted by the ESA advisory structure and a European
contribution to SPICA is undergoing an assessment study as a Mission of Opportunity within the ESA Cosmic Vision
1015-2015 science mission programme. In this paper we describe the elements that are being studied for provision by
Europe for the SPICA mission. These entail ESA directly providing the cryogenic telescope and ground segment
support and a consortium of European insitutes providing a Far Infrared focal plane instrument. In this paper we
describe the status of the ESA study and the design status of the FIR focal plane instrument.