The imaging fourier transform spectrometer for the SIMURIS mission

The Solar Interferometric Mission for Ultrahigh Resolution Imaging and Spectroscopy (SIMURIS) is an interferometric investigation in space at ultraviolet and visible wavelengths aimed at reconnaissance of solar features at angular scales from 0.3 to 0.01 arcsec. The Imaging Fourier Transform Spectrometer (IFTS) is, with the Solar Ultraviolet Network (SUN), one of the core instruments of the proposed SIMURIS mission. It consists of a 40 cm Gregory telescope feeding a double grating pre-dispersive spectrometer before entering a Fourier transform spectrometer for a field of 10 × 10 arcsec² at 0.3 arcsec resolution. The SIMURIS/IFTS requires upgrading of existing FTS down to 120 nm, with imaging capabilities. For the IFTS imaging a detector with fast readout must be used. There are also demanding constraints on the real time processing, and the subsequent important data rate, and requirements on an upgraded instrument pointing system (IPS), within the resources and capabilities of the Space Station.