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CHIME, the Copernicus Hyperspectral Imaging Mission for the Environment, is one of the six High Priority Candidate Missions (HPCM) of the evolution in the Copernicus Space Component (CSC) foreseen in the mid-2020s that is proposed for further analysis. In this paper we summarize the results as retrieved by OHB (D) as part of the Phase A/B1. The contract was kicked off in 2018 and concluded in 2020 after finalisation of the Pre-development activities. The proposed instrument is a hyperspectral imager instrument with reflective telescope and grating-based spectrometer. The selected orbit is in the range of 625 ± 30 km, LTDN 10:45 – 11:15 am with a repeat cycle of 20 to 25 days for a single satellite and 10-12.5 days revisit for 2 satellites. The payload of each satellite records at a Spatial Sampling Distance (SSD) of 30m the full spectral range from 400 to 2500nm at a Spectral Sampling interval < 10nm with Low Keystone/Smile. On the front end a high performance TMA with wide-band coated optics collects the light from ground and feeds it to a highly linear almost distortion free spectrometer assembly attaining very good spectral stability. All units are integrated in an optical bench structure that offers excellent AIT access and provides a highly stable LOS. The electro-optical backend contains low-noise cold MCT detectors creating margin in the predicted NEDL performance. The instrument can be calibrated via on-board devices or using reference targets outside the spacecraft. We present the functional decomposition and the physical instrument architecture: the optical design and opto-mechanical layout, the electro-optical imaging chain ant thermal control system.

Several chemicals which could be relevant for life processes are found in the upper atmosphere of Venus (H2S, OCS, SO2, NH4Cl, NH2COOHN4 and H2O). Moreover, the atmosphere instability and the reason for the high ultraviolet (UV) heterogeneous absorption between 320 and 400 nm in the top cloud layer and mesosphere (~ 40-70 Km) are still disputed phenomena. These scientific points could be further studied by small UV Raman and fluorescence instruments mounted in a small lander platform (< 20 kg) being send to Venus. In this current article we will propose an optical payload mission, which could be useful to give more information on these scientific questions. This study proposes a feasibility analysis for launching a small probe device that includes an emitting laser, a receiving telescope and a detector. The goal of this theoretical mission (UV-BIOmarker Mapper for Venus AtmosPhere or UV-BIOMAP) will be to analyse the laser-emitted and further absorption of UV light in the Venus atmosphere, and to verify the possible presence of biomarkers. The current state of the art of the required technologies to be implemented would allow a more cost-efficient and easy to develop mission, compared with previously completed Venus probes. This article will be focused on the required science and optical payload devices needed for solving these issues. Requirements for mass and power budgets for the optical payload will be analysed to ensure that the mission can be carried out at relatively low cost while still accomplishing the scientific goals of revealing the composition of Venus’s atmosphere in more detail and the reason for the heterogeneous UV absorption in the planet’s top cloud layer and mesosphere.

A mid-to-high resolution optical payload, named STREEGO, featuring a compact envelope, reduced mass, and competitive cost has been designed to address Earth Observation applications from low Earth orbit (LEO) small satellites. STREEGO is a fully reflective telescope designed for operation at a nominal altitude of 600 km to provide a ground sampling distance (GSD) of 2.75 m, a field of view of about 1° and a modulation transfer function (MTF) greater than 10p at Nyquist frequency (91 cy/mm) with a telescope aperture of 200 mm. A large two-dimensional CMOS sensor with a pixel size of 5.5 μm has been selected in order to obtain the requested GSD with a focal length of 1.2 m, and a signal-to-noise ratio equal to 75. A demonstration model is in the detailed design phase and will be developed, with completion planned by end of 2015. We present a detailed description of the instrument, which, by leveraging on aspheric surfaces and light-weight solutions, achieves remarkable performance in terms of compactness and image quality with less than 25 kg in mass. The optical design is based on a three mirror anastigmat (TMA) configuration whereby the mirrors are realized in metal with the same coefficient of thermal expansion of the structure in order to obtain an athermal design.