REVIEW ARTICLES CURRENT SCIENCE, VOL. 119, NO. 8, 25 OCTOBER 2020 1267 *For correspondence. (e-mail: tprateek59@gmail.com) First impressions from the PRISMA hyperspectral mission Prateek Tripathi* and Rahul Dev Garg Geomatics Engineering, Department of Civil Engineering, Indian Institute of Technology, Roorkee 247 667, India PRISMA is a hyperspectral mission launched by the Italian Space Agency on 21 March 2019. PRISMA is the spaceborne hyperspectral sensor which provides imageries of the Earth’s surface with (i) global cover- age of 30 km × 30 km with a total acquisition capacity of 1800 km in a continuous strip, and (ii) spectral res- olution of 12 nm for the contiguous bands (400– 2500 nm wavelength). This study presents a review of the hyperspectral datasets from PRISMA for geologi- cal applications. A few geological regions from India are selected to check the capability of the PRISMA datasets. Dimensionality reduction and spectral analy- sis were performed and narrowband indices were generated. Few constraints with the previous hyper- spectral sensors, i.e. large swath with a medium reso- lution camera on-board, are now covered in the PRISMA mission. This study is focused on the charac- teristics and compatibilities of the PRISMA hyper- spectral sensor and will be beneficial to the scientific and users community. Keywords: Geological applications, hyperspectral remote sensing, imaging spectroscopy, mineral exploration, spec- tral analysis. HYPERSPECTRAL remote sensing, also known as imaging Spectroscopy, acquires imageries in the wavelength range 380–2500 nm. This technique offers a dynamic and unique method to identify and characterize minerals in the visible and near-infrared (VNIR) and shortwave infra- red (SWIR) wavelength ranges. It collects data in narrow and contiguous bands that can be utilized in many fields like forest analysis, precision agriculture, inland and coastal waters, climate change and environmental research, raw materials exploration, mining–soil degradation and soil properties 1 . In the last few decades, several countries have used airborne and spaceborne hyperspectral sensors. There are a few hyperspectral missions, including NASA’s, Hyperion under earth observing 2 (EO)-1, Compact High- Resolution Imaging Spectrometer (CHRIS) on-board the Proba-1 (European Space Agency, ESA), which work with various view angles to measure spectral reflectance 3 . In 2018, the Indian Space Research Organization (ISRO) launched the hyperspectral imaging satellite (HySIS) 4 . These hyperspectral missions were launched to demon- strate the capabilities of high spectral resolution-based remote sensing techniques for the development of various algorithms and related applications. These hyperspectral missions encouraged the research community to develop various algorithms and methods in the domain of mineral exploration. However, unfortunately, none of these satel- lites provides the latest global processed datasets to the research community. The Italian Space Agency launched the hyperspectral satellite 5 , PRISMA (PRecursore IperSpettrale dellaMis- sione Applicativa) on 21 March 2019 (French Guiana). PRISMA operates in two modes, one for downloading of the data, and another for acquisition and downlinking 6 . The main aim of this mission is to provide remote sensing datasets to the scientific and student community for earth observation and risk management 7 . On 21 May 2020, the Italian Space Agency made the PRISMA datasets free to download for its users 8 . It is a massive relief to the hyper- spectral community as this mission is still in acquisition mode; hence, allowing users to request new datasets. This study presents an overview of the PRISMA hyperspectral mission, a few datasets and their capability in geological applications. PRISMA mission: architecture, specifications and modes of acquisition PRISMA instrument works on the concept of the push- broom imaging scanning 9 . With an operational lifetime of five years, the satellite is mainly composed of the electro- optical payload, and the payload data handling and transmission subsystem (PDHT). The PRISMA payload has an imaging spectrometer (or hyperspectral imager) to capture images in a series of contiguous spectral bands covering the wavelength range from 400 to 2500 nm, and a panchromatic camera with a resolution of 5 m that can be fused with other multispectral sensors available for improved visual image interpretation and information retrieval 1,10 (Table 1). The PRISMA system has a daily imaging capability 1,6 of ~200,000 sq. km, and can deliver the hyperspectral imagery for the area of interest (Figure 1). The primary area of interest covers the 180°W–180°E long and 70°S to 70°N lat. PRISMA delivers four types of standard products (Table 2).