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Aims. The Spectral Imaging of the Coronal Environment (SPICE) instrument is a high-resolution imaging spectrometer operating at extreme ultraviolet (EUV) wavelengths. In this paper, we present the concept, design, and pre-launch performance of this facility instrument on the ESA/NASA Solar Orbiter mission. Methods. The goal of this paper is to give prospective users a better understanding of the possible types of observations, the data acquisition, and the sources that contribute to the instrument's signal. Results. The paper discusses the science objectives, with a focus on the SPICE-specific aspects, before presenting the instrument's design, including optical, mechanical, thermal, and electronics aspects. This is followed by a characterisation and calibration of the instrument's performance. The paper concludes with descriptions of the operations concept and data processing. Conclusions. The performance measurements of the various instrument parameters meet the requirements derived from the mission's science objectives. The SPICE instrument is ready to perform measurements that will provide vital contributions to the scientific success of the Solar Orbiter mission.

SPICE is a high resolution imaging spectrometer operating at extreme ultraviolet wavelengths, 70.4 -79.0 nm and 97.3 -104.9 nm. It is a facility instrument on the Solar Orbiter mission. SPICE will address the key science goals of Solar Orbiter by providing the quantitative knowledge of the physical state and composition of the plasmas in the solar atmosphere, in particular investigating the source regions of outflows and ejection processes which link the solar surface and corona to the heliosphere. By observing the intensities of selected spectral lines and line profiles, SPICE will derive temperature, density, flow and composition information for the plasmas in the temperature range from 10,000 K to 10MK. The instrument optics consists of a single-mirror telescope (off-axis paraboloid operating at near-normal incidence), feeding an imaging spectrometer. The spectrometer is also using just one optical element, a Toroidal Variable Line Space grating, which images the entrance slit from the telescope focal plane onto a pair of detector arrays, with a magnification of approximately x5. Each detector consists of a photocathode coated microchannel plate image intensifier, coupled to active-pixel-sensor (APS). Particular features of the instrument needed due to proximity to the Sun include: use of dichroic coating on the mirror to transmit and reject the majority of the solar spectrum, particle-deflector to protect the optics from the solar wind, and use of data compression due to telemetry limitations.

As the measurement techniques 12 in the space science community rapidly evolve, the demand for multichanneled, high-speed, radiation tolerant data acquisitioning systems gets increasingly higher. The high volume and resolution of data, and the complexity of the in-situ processing and analysis requirements, have triggered the need for faster, smaller, and easily reconfigurable designs.In response to this demand, Southwest Research Institute has developed a high-speed, multi-channel, versatile data acquisitioning architecture. This new architecture can perform reconfigurable DSP algorithms and subsequent data processing on instrument analog input signals. The overall architecture and topology was developed as part of a SwRI science instrumentation trade study and then implemented on the NASA Gamma-ray Large Area Space Telescope (GLAST) Data Processing Unit (DPU). It can easily be reconfigured for other space missions and instrument applications.This paper presents an architectural view of the design and gives examples of its tremendous versatility. It also addresses the evolution of analog DSP data acquisition systems in general and emphasizes the advantages and tradeoffs between today's approaches versus older heritage methods.

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