PRISMA2GEN

Quick facts

Overview

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Summary

Mission Capabilities

PRISMA2GEN will carry two instruments, a hyperspectral camera and a panchromatic camera. The hyperspectral camera is a two-band prism spectrometer that will collect high resolution hyperspectral imagery of land, vegetation, inner waters and coastal zones, while the panchromatic camera will mainly provide supplementary imagery for data processing.

Performance Specifications

The PRISMA2GEN hyperspectral camera has a spectral range of 400 nm - 2505 nm across 237 channels, with a channel bandwidth of 10 nm. It will image in two bands, one in the Visible to Near Infrared (VIS/NIR) range, and one in the Near Infrared to Shortwave Infrared (NIR/SWIR) range, with 10 m spatial resolution across all bands.

Both PRISMA2GEN and PLT-4 will be launched into a sun-synchronous orbit at an altitude of 515 km, enabling a low revisit time of 72 hours, with a maximum off-nadir angle of 32°.

Space and Hardware Components

The PRISMA2GEN bus is expected to weigh approximately 1000 kg and feature an electric propulsion system (EPS), which will improve the satellite’s operating lifetime. The ground segment will be designed by Telespazio.

Overview

The Second Generation Hyperspectral Applications Precursor Mission (PRISMA2GEN) is a hyperspectral remote imaging mission of the Italian Space Agency (ASI) currently in development in conjunction with Thales Alenia Space. PRISMA2GEN is the successor to the PRISMA mission, launched in 2019, and aims to build on its successes by improving the spatial resolution of hyperspectral imagery, improving the quality of imagery of land, vegetation, inner waters and coastal zones. The mission will ensure data continuity from the existing PRISMA satellite, and is planned to consist of a single high performance satellite, and a smaller satellite, Platino-4 (PLT-4), based on the successful design of the Platino microsatellite platform. PRISMA2GEN improves on its predecessor by offering higher spatial resolution imagery and greater platform agility and manoeuvrability, improving the system’s responsiveness to real-time data requests.

Spacecraft

While the design specifications of the satellite buses have not yet been confirmed, the main PRISMA2GEN satellite is expected to weigh approximately 1000 kg, while the accompanying satellite PLT-4 will weigh an estimated 300 kg. PRISMA2GEN aims to be entirely electrically powered by an electric propulsion system (EPS). The EPS will function by collecting energy through its solar arrays and use this power to ionise an inert gas propellant (usually Xenon or Krypton). Using either a combination of electric and magnetic or electrostatic fields to accelerate these ionised particles, the EPS ejects them from a thruster, generating force, as shown in Figure 1. The ionisation of propellants greatly enhances the fuel efficiency by allowing greater acceleration of particles, imparting more force on the satellite bus.

Launch

Both PRISMA2GEN and PLT-4 will be launched into a sun-synchronous orbit at an altitude of 515 km. The two satellites will fly in formation during the first phase of the mission, observing the same scenes to allow for cross-calibration checks, before separating by 180°.

Mission Status

• February 21, 2022: Thales Alenia Space signed a contract with ASI to conduct a feasibility study of the PRISMA2GEN mission. 11)
• June 26, 2021: The “Hyperspectral Remote Sensing Consultation Process: beyond PRISMA Mission” survey closed, finding user demand for both Stripmap and Spotlight imaging modes, as well as a high signal to noise ratio, high spatial resolution and a large quantity of images. 1)
• March 22, 2019: The PRISMA mission was successfully launched into orbit aboard a Vega-5 rocket. 7)

Sensor Complement

PRISMA2GEN will carry two instruments, a hyperspectral camera (known as HYC2) and panchromatic camera, that will both be designed and manufactured by the Italian headquartered aerospace company Leonardo.

Hyperspectral Camera 2 (HYC2)

HYC2 is a prism spectrometer for two bands with a spectral resolution of 10 nm. The two selected bands will be in the visible to near infrared (VIS/NIR) range and in the near infrared to shortwave infrared (NIR/SWIR) range, with a total of 237 channels across the two bands. HYC2 has a swath width of 30 km and a spatial resolution of 10 - 30 m across all channels and bands. The data collected by HYC2 will primarily be used in analysis of vegetation, such as in precision agriculture. This application in vegetation analysis in particular comes from the higher reflectance spectra provided by PRISMA2GEN hyperspectral imagery, which means it has greater potential for analysis of biophysical parameters than it does for other applications.

Panchromatic Camera

The PRISMA panchromatic camera is a high resolution optical imager with a signal to noise ratio of 240 and a spatial resolution of 5 m at the sub-satellite point. The panchromatic camera is mainly intended to provide supplementary imagery to be used in data processing and as a reference point for collected hyperspectral imagery.

Both the hyperspectral and panchromatic cameras are capable of both stripmap and spotlight imaging modes, through satellite pointing, as shown by Figure 2. Stripmap imaging refers to imaging the area beneath the satellite, collecting data over a larger area. Spotlight imaging however, involves pointing the satellite to face a single point as it passes, capturing multiple angles of the same scene and providing greater details and finer resolution over a smaller area. For the PRISMA2GEN mission, stripmap imaging will provide a Ground Sample Distance (GSD) of less than 30 m for hyperspectral imagery, and less than 5 m for panchromatic imagery, with indefinite stripmap length. PRISMA2GEN has a daily stripmap imaging capacity of greater than 2,000,000 km2. For spotlight imaging, PRISMA2GEN is capable of capturing hyperspectral imagery with a GSD of less than 10 m, and panchromatic imagery with a GSD of less than 2.5 m. Spotlight imagery has a swath width of 30 km, at a length of up to 210 km, with a daily spotlight imaging capacity of more than 200,000 km2.

Ground Segment

The PRISMA ground segment has been designed by Telespazio. In addition to this, Telespazio is also conducting a study on the system requirements and will design the program architecture.

References  

1) Ansalone, L. THE PRISMA AND PRISMA-PSG MISSIONS status and updates Luigi ANSALONE – ASI, 4 October 2022, URL: https://hyperspectral2022.esa.int/iframe-agenda/files/presentation-187.pdf

2) “Current and future Earth Observation missions.” ASI, URL; https://www.asi.it/wp-content/uploads/2021/09/00.ASI-UOT-Presentation-ASI-Longo-20211104_V01.pdf

3) “Electric Propulsion – Basic Concept.” LinkedIn, 18 November 2019, URL: https://www.linkedin.com/pulse/electric-propulsion-basic-concept-herald-sukasi-1c

4) “HYC.” WMO OSCAR, URL: https://space.oscar.wmo.int/instruments/view/hyc

5) Muff, Darren. “Figure 1.4: Comparison of Strip-Map and Spotlight Modes of SAR Operation.” ResearchGate, URL: https://www.researchgate.net/figure/Comparison-of-Strip-Map-and-Spotlight-Modes-of-SAR-Operation_fig4_327728723

6) “PAN.” WMO OSCAR, 25 July 2022, URL: https://space.oscar.wmo.int/instruments/view/pan

7) “PRISMA.” ASI | Agenzia Spaziale Italiana, URL: https://www.asi.it/en/earth-science/prisma/

8) “PRISMA 2 Gen.” WMO OSCAR, URL: https://space.oscar.wmo.int/satellites/view/prisma2gen

9) “PRISMA Second Generation (PSG) soon to kick off.” Telespazio, URL: https://www.telespazio.com/en/news-and-stories-detail/-/detail/prisma-second-generation

10) “The Propulsion We’re Supplying, It’s Electrifying.” NASA, 22 October 2020, URL: https://www.nasa.gov/humans-in-space/the-propulsion-were-supplying-its-electrifying/

11) “The Second-Generation PRISMA Earth Observation System Gets Underway: the Consortium Led by Thales Alenia Space Signs the Feasibility Study Contract with Italian Space Agency.” Thales Group, URL: https://www.thalesgroup.com/en/worldwide/space/press-release/second-generation-prisma-earth-observation-system-gets-underway

12) Shaik, Riyaaz Uddien. “Potential Assessment of PRISMA Hyperspectral Imagery for Remote Sensing Applications.” MDPI, URL:  https://www.mdpi.com/2072-4292/15/5/1378

13) “Thales Alenia and ASI work on second-generation PRISMA system.” URL: SpaceWatch, https://spacewatch.global/2022/02/thales-alenia-and-asi-work-on-second-generation-prisma-system/