The PRISMA (PRecursore IperSpettrale della Missione Applicativa) Earth Observation program is one the most important Italian investments in the field of Remote Sensing. Fully funded by the Italian Space Agency (ASI) and based on the Italian Industries status of the art technology. PRISMA will provide images acquired by an innovative electro-optical instrument using an Imaging Spectrometer, able to acquire in contiguous spectral bands ranging from 400 to 2500 nm, optically integrated with a medium resolution Panchromatic Camera (PAN).
The PRISMA System includes:
- a Space Segment, consisting in a single satellite placed in suitable LEO Sun synchronous orbit, at about 620 km above the Earth surface, with an operational lifetime of 5 years. The revisit time will be approximately 6 days. The satellite will be composed by a Platform, a Payload consisting in a Hyperspectral/Panchromatic instrument and a Payload Data Handling and Transmission subsyatem;
- a Launch Segment. The VEGA has been selected as PRISMA launcher;
- a Ground Segment, comprising various centres located in Italy: a Mission Control Centre (MCC) in charge of mission planning and management, a Satellite Control Centre (SCC) in charge of satellite command and control, and a Payload Ground Segment (IDHS) in charge of P/L data reception, archiving and processing and interface with users.
The PRISMA payload uses pushbroom scanning technique to collect PAN/HYP image strips up to 1800 km in length and along sub-satellite track. Several additional data (e.g. calibration data, etc.), as necessary, is also provided for the on ground processing. PRISMA images Swath is 30 km width and the Ground Sampling Distance is 30 m (hyperspectral) and 5 m (panchromatic) at Nadir. PRISMA has also the agility to acquire data up to +/-20.7° off-nadir.
PRISMA operates both as a primary mode, “user driven”, collecting hyperspectral (HYP) and panchromatic (PAN) data requested by end users over specific targets and a secondary mode, “background”, acquiring imagery to fully exploit the satellite and downlink resources.
PRISMA Ground Segment can generate different products: Level 0 - (L0) raw data stream including instrument and satellite ancillary data; Level 1 (L1)-TOA (Top Of Atmosphere) radiometrically and geometrically calibrated HYP and PAN radiance images; Level 2 (L2) - Geolocated and Geocoded Atmospherically corrected HYP and PAN images, atmospheric constituent maps (aerosols, water vapour, thin cloud optical thickness). L1 and L2 products are generated on demand, upon user request, from archived L0 products (raw data stream including instrument and satellite ancillary data).
The main objective of the PRISMA program is to give an innovative contribution to Earth Observation applications, thanks to the combined use of hyperspectral and panchromatic. Providing both the capabilities of recognition of the geometric characteristics of the observed target and of extraction of the chemical characteristics of the constituent’s materials, the PRISMA mission can give a contribution in the field of vegetation and forest monitoring, precision agriculture, water quality assessment, raw materials and soils properties observation.
This paper report an overview of the PRISMA program.

PRISMA (PRecursore IperSpettrale della Missione Applicativa) is an Italian program fully funded by the Italian Space Agency and based on the Italian Industries status of the art technology. The satellite launch is scheduled by February 2019 with the VEGA Launcher and the foreseen operational life of the mission is five years.
The PRISMA Hyperspectral Payload is an Electro-Optical instrument composed of a hyperspectral imager optically integrated with a medium resolution panchromatic camera.
The two main modules of the Payload are the Optical Head (OH) and the Main Electronics (ME) box.
The optical design is based on high transmittance optical assemblies, including a reflective common telescope in Three-Mirror Anastigmat (TMA) configuration, a single slit aperture, a panchromatic camera (700-900 nm) and a spectrometer operating in Visible and Near Infrared (VNIR) and Short Wave Infrared (SWIR) regions, therefore covering the wavelength range between 400 and 2500 nm. The Panchromatic (PAN) images are provided at higher spatial resolution in order to allow for images fusion techniques (i.e. “pan sharpening”).
The Main Electronics box controls the Optical Head, manages power supply distribution and interfaces the Platform On Board Data Handling (OBDH) and Payload Data Handling and Transmission (PDHT) modules, therefore handling tele-commands and telemetries and channeling scientific data.
The main design challenges and trade-offs were related to:
• Very demanding SNR requirements, even in comparison with more recent space payloads, reducing trade-off options and triggering higher system complexity and technical risks. This has implied the need for a large main aperture (F-number 2.9) and the selection of a prisms-based spectrometer (instead of using gratings)
• The constraints on the thermal design, related to the use of a passive cooling system to avoid the problems related to the active device (lifetime, mass, power consumption, exported torque and micro-vibrations) and therefore to fit mission requirements, including MTF – and the need of supporting several significant dimensioning thermal cases in conditions of non-Nadir pointing (i.e. rolling)
• The large number of bands to be acquired and the consequent high data volume imposing the need for the implementation of a (lossless) compression board significantly increasing the complexity of the Main Electronics design.
Due to the demanding requirements on the radiometric accuracy, an in-flight Internal Calibration Unit (ICU) is present in order to allow absolute and relative radiometric calibration, and spectral calibration.
The assembly and integration of the Payload was completed in 2018; then the instrument underwent extensive testing and qualification (including structural, thermal, electrical, functional and EMC validation) and a complete characterisation campaign. The processing of all the acquired data is currently ongoing, with the purpose of finalising the Characterisation and Calibration Data Base parameters.
The Payload has been successfully integrated into the PRISMA platform and is currently undergoing Satellite-level acceptance tests.

PRISMA (PRecursore IperSpettrale della Missione Applicativa) is a medium-resolution hyperspectral imaging mission of the Italian Space Agency (ASI) mainly focused on the development and delivery of hyperspectral products and the qualification of the hyperspectral payload in space. The overall mission objective is to provide a global observation capability.
In this context, the PRISMA system results structured in a space segment represented by a satellite placed in a LEO sun syncronous orbit and a Ground Segment (GS) comprising various centers. More specifically, PRISMA GS is geographically distributed in Italy and it performs the following basic functions: 1) Satellite Control & Monitoring, 2) Mission Programming, 3) Mission Exploitation, 4) User Services. For this purpose, it includes two main elements: the Mission Planning and Control (MPC) and the Instrument Data Handling System (IDHS), located in Fucino and Matera Space Center respectively. At MPC refer the functions 1) and 2) while IDHS is in charge for the functions 3) and 4). Therefore, in the former centre are focused the activities of telemetry (TM) and telecommand handling, database definition, orbit management, TT&C and mission programming. It is used a S-band link for communication of telemetry and command data with the spacecraft (Fucino Center).
The MPC hosts the following subsystems: Satellite Control System (SCS), for monitoring and controlling the satellite; Flight Dynamics System (FDS), which takes care of orbit and attitude operations; TT&C Station providing the S-band interface between satellite and GS; Mission Planning System (MPS) providing the mission planning and related tasking sequences generation. The SCS and the FDS co-operate for the flight dynamics activities: FDS receives raw data (TM, ranging etc.) from SCS and returns processed products (e.g. predicted orbital data, manoeuvre parameters etc.). From a logical point of view, SCS acts like a gateway toward the rest of MPC as TT&C station is made to be a hardware unit with limited intelligence while FDS is a service provider of a single defined output without precise knowledge of the community of its clients. On the other hand, MPS provides capabilities for coordinate the on-board and ground activities, performing overall mission planning, allocating resources and solving conflicts. Its objective is to produce a conflict-free plan of activities for the near future time span (nominally 24 hours) matching the users acquisition requests by optimising system performances.
The IDHS is dedicated to the support at the request submission, catalogue browsing and query, acquisition, archiving and processing of the collected data; it is used a X-band downlink for the image and ancillary data (ASI Matera Space Geodesy Centre). The IDHS data processing function is devoted to generate Level 0, Level 1 and Level 2 products. The end users can access PRISMA mission data (catalogue and new acquisition requests) through a unique web access point named CAS (CNM Access System). Quality of the products delivered to end users is maintained through the functions provided by the PRISMA Calibration Facility, which is hosted in the IDHS, too. A dedicated communication local network (WAN/LAN) implements the connections between the different GS entities in a secure, reliable and efficient way. The presentation will provide the description of the PRISMA Ground Segment, as designed, developed, qualified and accepted while the mission evolves towards operational use.

PRISMA (PRecursore IperSpettrale della Missione Applicativa) is an Italian program fully funded by the Italian Space Agency and based on the Italian Industries status of the art technology. The satellite launch is scheduled for February 2019 with VEGA Launcher. PRISMA satellite has been designed for a mission lifetime of five years.
The PRISMA hyperspectral sensor is realized as a pushbroom imaging spectrometer. It is able to take images in a continuum of spectral bands ranging from 400 to 2500 nm, for VNIR (visible and near infrared) with 66 bands and for SWIR (shortwave infrared) with 174 bands, and a medium resolution Panchromatic Camera (400-700 nm). The image data is collected, formatted to CCSDS standards and sent to the Satellite on-board mass memory and downlink units. PRISMA can support many Earth Observation applications thanks to both its Ground Sampling Distance of 30 m × 30 m for hyperspectral images and 5 m × 5 m for Panchromatic images at Nadir.
Several PRISMA products levels can be delivered to the end users. The PRISMA Level 0 (L0) are raw data products, including instrument and satellite ancillary data. The first step of the instrument raw data processing (Level 0) includes error detection and correction (through a Reed Solomon decoder), decompression (in case of compressed hyperspectral data), CCSDS packet recognition, data type discrimination, as well as the generation of L0 products and their relevant metadata and cloud coverage percentage computation. Starting from L0 product the PRISMA Quicklook (QL) product is generated and is associated to each archived product to support the user in data selection.
The Level 1 Processor is in charge of retrieving physical quantities (i.e. the spectral radiance) from input L0 products, through the application of appropriate calibration and characterization parameters. The PRISMA Level 1 (L1) Product is the Top Of Atmosphere (TOA), radiometrically and geometrically calibrated HYP and PAN radiance images. It consists of a file in the HDF-EOS5 format that reports, for the input L0 Earth Observation, the list of radiance frames and the relevant attributes.
The Level 2 processing is devoted to the generation the L1 Top-of-Atmosphere (TOA) spectral radiance into geophysical parameters (L2b, L2c e L2d). These parameters depend on the observed pixels and provide information on the at-surface radiance/reflectance and the properties of the atmosphere above the surface (Aerosol Optical Thickness and Angstrom Exponent, Water Vapor Content, Thin Cloud Optical Thickness).
The PRISMA Level 2 (L2) Product is Geolocated and Geocoded Atmospherically corrected HYP and PAN images, atmospheric constituent maps (aerosols, water vapor, thin cloud optical thickness). In particular, the atmospheric correction process generates both Bottom Of Atmosphere (BOA) radiance and reflectance. These two quantities are stored respectively into Level 2b and 2c PRISMA products, respectively. The highest processing level of the PRISMA production chain is the geocoding of the Level-2c products, applying the geometric model already provided in L2b and L2C, and generating the UTM projected and orthorectified L2d Product, with the support of DSM.
L1 and L2 products are generated on demand, upon user request, from archived L0 products or for a new image acquisition request.
The end users can access via web to PRISMA mission data (catalogue and new acquisition requests) through a unique access point named CNM Access System (CAS).
In order to maintain the PRISMA image quality, a series of calibration campaigns are foreseen during both the commissioning and the operational phase throughout the instrument lifetime. The PRISMA payload is provided with an on-board Calibration Unit that allows in-flight calibration. Moon and Sun calibration are also foreseen. Calibration measures are performed during the IOT (In-Orbit Test) and then compared with the On-ground Calibration executed before the launch.
For verifying the correctness of the PRISMA products generated during system operations, a systematic validation process is envisaged both during the commissioning phase and during the operational phase. Validation involves the assessment of the accuracy of the data and products, over the relevant spatial and temporal domains. The overall approach for validation is based on an extensive use of ground-based datasets. The PRISMA Calibration/Validation (Cal/Val) Plan is under definition.
This paper describes PRISMA products that are planned for archiving and/or operational distribution to users.

PRISMA (PRecursore IperSpettrale della Missione Applicativa) is the mission funded by the Italian Space Agency with the aim of developing a satellite equipped with a new generation of hyperspectral optical sensor for Earth observation on global scale. The mission is developed in all its parts (space segment and ground segment) by a consortium of Italian industrial companies. PRISMA is conceived as a pre-operational and technology demonstrator project, focused on the development and delivery of hyperspectral products, for the exploitation of the mission data, and the qualification of the hyperspectral payload in space.
The PRISMA mission has the capability to acquire a considerable amount of data, with innovative information content compared to the already existing missions and with unique application potentials, also combining hyperspectral data with traditional radar and optical data. The payload consists of a high spectral resolution spectrometer optically integrated with a medium resolution panchromatic camera.
The PRISMA system can acquire, downlink and archive images of all hyperspectral/panchromatic channels up to 200,000 km2 daily, worldwide on the primary area of interest ranging from 180 ° W to 180 ° E of longitude and from 70 ° S to 70 ° N of latitude. The PRISMA mission can operate in two modes: in the user driver mode, hyperspectral and panchromatic data are acquired on specific targets requested by end users, while in the data driver mode, background acquisition are generated automatically to fill system resources such that the satellite and downlink resources are fully used. The Primary and Background Operational modes can be present simultaneously/alternately during the same acquisition plan
The PRISMA products can be delivered to users as Level 1 TOA (Top Of Atmosphere) radiometrically and geometrically calibrated HYP and PAN radiance images or Level 2 Geolocated and Geocoded Atmospherically corrected HYP and PAN images with atmospheric constituent maps (aerosols, water vapour, thin cloud optical thickness). L1 and L2 products are generated on demand, upon user request, from archived L0 products (raw data stream including instrument and satellite ancillary data). The end users can access via web to PRISMA mission data (catalogue and new acquisition requests) through a unique access point named CNM Access System (CAS). The user has to be registered to submit new acquisition data request to the Mission Planning system and/or to access the catalogue browser and to require level 1 or Level 2 products from archive data.
As the first European Earth Observation satellite hyperspectral mission, PRISMA has a strategic importance in the international scenario giving the opportunity to develop strategic know how, to explore innovative data processing and products application.
In that framework ASI intends to pursue the full exploitation of the technological potential of PRISMA products, by applying data access tools and data policy able to support the development of new products for applications. The main advantage that the combined hyperspectral and panchromatic products give the capability of recognition of the geometric characteristics of a scene and may provide detailed information about the chemical composition of materials and objects on the Earth surface, giving enormous impacts to remote sensing applications. The main benefits are expected in the field of forest monitoring, precision agriculture, water quality (e.g., chlorophyll monitoring, alga bloom), climate change and environmental research (e.g., desertification, deforestation, vegetation stress), Soil degradation and soil properties, Raw material exploration and mining.
The aim of this paper is to give an overview of the PRISMA Mission Management strategies, Data Policy and Operational Plan, highlighting the main opportunities for the science and application user community in the current and future earth observation scenario.