GLIMR (Geostationary Littoral Imaging and Monitoring Radiometer)

Quick facts

Overview

Related Resources

Summary

Summary

Mission Capabilities

The GLIMR instrument is a hyperspectral imager currently being developed by Raytheon Intelligence and Space. It will provide high-sensitivity measurements of marine ecosystems with high spatial and temporal resolution across the visible, infrared, and ultraviolet spectrum. The GLIMR instrument will measure the wavelength of sunlight scattered from the surface of the ocean, known as the ocean colour, to derive concentrations of chlorophyll, suspended sediment, and dissolved organic matter.

Performance Specifications

GLIMR will be launched into a geostationary orbit positioned above the Gulf of Mexico at an altitude of 36,000 km. It will image in the ultraviolet, visible and near-infrared bands between 340 and 1040 nm, with sampling at 5 nm intervals. GLIMR will have a nadir-view of the Earth with a spatial resolution of 391 m and a swath field of view of 20.8°. GLIMR will have a high signal to noise ratio and will monitor the Gulf of Mexico and surrounding areas for up to 15 hours per day, with up to six revisits per day for the coastal United States.

Space and Hardware Components

Built by Raytheon Intelligence and Space, the GLIMR instrument has a telescope on a two-axis gimbal, which will provide access to regions of interest across the entire Earth through N-S and E-W motions. The GLIMR instrument will be mounted to the Nadir deck of a NASA spacecraft once the instrument is complete

Overview

The Geostationary Littoral Imaging and Monitoring Radiometer (GLIMR) is a hyperspectral instrument that will capture highly detailed images of physical and biological conditions in coastal waters in the Gulf of Mexico, selected coastal regions of North and South America, and the Amazon River plume – where the waters of the Amazon River enter the Atlantic Ocean. It will provide observations of rapidly evolving processes of phytoplankton physiology, growth and bloom evolution, and episodic and seasonal river-to-sea fluxes of materials. Observations from GLIMR will assist in the identification and tracking of oil spills and harmful algae blooms like Karenia brevis. Data from GLIMR will be used to respond rapidly to natural and manmade coastal water disasters as well as to help improve coastal ecosystem sustainability and resource management. 1) 2)

NASA's lead organisation for the GLIMR contract, The University of New Hampshire, has partnered with the National Oceanic and Atmospheric Administration (NOAA) to develop NASA’s first hyperspectral imager in geostationary orbit.  3) 4)

GLIMR will measure the reflectance of sunlight from coastal waters in narrow wavebands. Operating from a geostationary orbit, GLIMR will be the first hyperspectral ocean colour sensor in the Western Hemisphere to study ocean processes for up to 15 hours a day, which would not be possible from a satellite in a low-Earth orbit. Given its high spatial and temporal resolution, GLIMR will be highly complementary to other low-Earth orbit satellites that observe the ocean. 3) 5)

Spacecraft

The GLIMR mission will consist of the GLIMR instrument, currently being developed by Raytheon Intelligence and Space, integrated on a NASA-selected platform and will have a two-year on-orbit life. The GLIMR satellite is designed to have a mass of approximately 156 kg and 237 W of power. The instrument is currently being developed by Raytheon Intelligence and Space and will be integrated with a NASA satellite, which will also include a separate single-band imager, the Landmark Imager (LMI), which will image fixed features for navigation and registration. The GLIMR instrument has a telescope on a two-axis gimbal to actively scan the Hyperspectral imager and LMI through North-South and East-West motions. 4) 6)

Launch

GLIMR is planned to be launched into a geostationary orbit between 88°W and 108°W longitude. (above the Gulf of Mexico) at an altitude of 36,000 km. 1) 6)

Mission Status

• October 18, 2023: The GLIMR team presented updates and overview of the GLIMR development at the International Ocean Colour Science meeting. 7)
• June 2023: The GLIMR project completed the Completed Critical Design (CDR) Review. 8)
• March 21, 2023: GLIMR was approved to go forward with the final design and fabrication of the instrument, within the principal investigator-managed cost cap of $109.8 million. 9)
• September 16, 2022: The GLIMR applications workshop was held to discuss how measurements from the vantage point of geostationary orbit offer an unprecedented potential to benefit society, inform stakeholders, and support ecological decision-making. 7)
• 2018: The GLIMR instrument was selected from eight proposals considered under NASA's fifth EVI solicitation and was awarded $107.9 million for the project. 2)

Sensor Complement

The GLIMR instrument will provide hyperspectral, high-spatial, high-temporal measurements of coastal ecosystems with a high Signal to Noise Ratio (SNR). The GLIMR satellite will also host a single-band Landmark Imager (LMI) with a Ground Sampling Distance (GSD) of 133 m, which will provide high spatial resolution observations of landmarks with a refresh rate high enough to meet GLIMR georegistration requirements. 4) 6)

GLIMR Hyperspectral Instrument (HSI)

GLIMR has a median 391 m spatial resolution, which ranges from approximately 328 m over the Gulf of Mexico to 500 m over coastal and continental parts of the United States. This is within the range capable of resolving oil spills and imaging most sub-estuaries along the United States’ coastline. It will have a swath field of view of 20.8° North-South and East-West. The required performance goal for ocean colour products is 0.5% uncertainty for Top-of-Atmosphere (TOA) radiance. GLIMR aims to achieve ~0.5% uncertainty in TOA radiances in the UV-VIS range. 10) 11)

Across the visible wavelengths, the signal to noise ratio (SNR) is sufficient for identifying oil spills at the default scan time as well as at double this scan time (Table 2). 13)

Table 2: SNR overview of the GLIMR instrument 13)

Temporal resolution ranges from 6 to 15 hours in a day, with up to six revisits per day for the coastal United States. Sub-daily, hyperspectral observations from GLIMR may supplement existing water quality observations particularly at lower latitude coastal areas. 12)

Ground Segment

The Science Data Segment (SDS) for GLIMR is the science data processing and archiving centre for all GLIMR data. It is co-located with the Ocean Biology Processing Group (OBPG) at the NASA Goddard Spaceflight Center in Greenbelt, Maryland, USA.

The Science Operations Center (SOC) serves as the central command centre for all GLIMR science operations, such as monitoring and maintaining instrument health and safety, development and testing of command uploads, and SOC network connectivity and security. It is located within the Institute for the Study of Earth, Oceans and Space at the University of New Hampshire (UNH) in Durham, NH, USA. 14)

The Ocean Biology Distributed Active Archive Center (DAAC) is co-located with GLIMR SDS and distributes GLIMR science data and products acquired or produced by the SDS. The GLIMR satellite will have an output data rate of approximately 50 Mbps and the data will be available to scientists, researchers and educators around the world soon after its launch. 2) 4)

References  

1. GLIMR Mission Summary. The CEOS Database. Committee on Earth Observation Satellites (CEOS). ESA. August 23, 2023. URL: https://database.eohandbook.com/database/missionsummary.aspx?missionID=924 

2. Communications RC. Raytheon: RTX space sensor to monitor coastal ecosystem health.  Raytheon News Release Archive. Published Aug 14, 2023. URL: https://raytheon.mediaroom.com/2023-08-14-RTX-space-sensor-to-monitor-coastal-ecosystem-health 

3. Geosynchronous Littoral Imaging and Monitoring Radiometer (EVI-5).  NASA’s Earth Observing System. Last updated January 19, 2023. URL: https://eospso.nasa.gov/missions/geosynchronous-littoral-imaging-and-monitoring-radiometer-evi-5 

4. Berkovitz D. The Present GLIMR Instrument: Geostationary Littoral Imaging and Monitoring Radiometer (GLIMR) Instrument Capability and Overview. International Ocean Colour Science Meeting 2023, St. Petersburg, Florida. August 22, 2023. URL: https://eos.unh.edu/sites/default/files/media/2023/11/the-present-glimr-instrument_berkovitz.pdf 

5. Mohr K. GLIMR. NASA Earth Sciences. May 8, 2024. URL: https://earth.gsfc.nasa.gov/ocean/missions/glimr 

6. University of New Hampshire. GLIMR Instrument. Institute for the Study of Earth, Oceans, and Space. URL: https://eos.unh.edu/glimr/glimr-instrument 

7. University of New Hampshire. GLIMR Events. Institute for the Study of Earth, Oceans, and Space. URL: https://eos.unh.edu/glimr/events 

8. Salisbury J. GLIMR Updates: Geostationary Littoral Imaging and Monitoring Radiometer (GLIMR). International Ocean Colour Science Meeting 2023, St. Petersburg, Florida. October 18, 2023. URL: https://eos.unh.edu/sites/default/files/media/2023/11/glimr-updates_salisbury.pdf 

9. Fox K. Geosynchronous Littoral Imaging and monitoring radiometer -. NASA Blogs. March 24, 2023. URL: https://blogs.nasa.gov/glimr/ 

10. Mannino A. Bridging Instrument and Science Capabilities and Performance. International Ocean Colour Science Meeting 2023, St. Petersburg, Florida. October 18, 2023. URL: https://eos.unh.edu/sites/default/files/media/2023/11/bridging-instrument-and-science-capabilities-and-performance_mannino.pdf 

11. Mannino, S., Salisbury, J. and Tzortziou, M. Update on Geostationary Littoral Imaging and Monitoring Radiometer, University of New Hampshire Biological Diversity and Ecological Conservation Conference Day 2. 2023. URL: https://cce-datasharing.gsfc.nasa.gov/files/conference_presentations/jsw2023/BDEC_presentations/DAY2/1430_Mannino_FINAL%20-%20An.pdf 

12. Schaeffer B, Whitman P, Vandermeulen R, Mannino A, Salisbury J. Potential for Geostationary Littoral Imaging and Monitoring Radiometer (GLIMR). International Ocean Colour Science Meeting 2023, St. Petersburg, Florida. November 17, 2024. URL: https://cfpub.epa.gov/si/si_public_record_Report.cfm?dirEntryId=360969&Lab=CEMM 

13. Tzortziou M, Turner W. GLIMR Applications Update: A Geostationary Sensor for a Dynamic Coastal Ocean. International Ocean Colour Science Meeting 2023, St. Petersburg, Florida. October 18, 2023. URL: https://eos.unh.edu/sites/default/files/media/2023/11/glimr-applications-update_tzortziou.pdf 

14. University of New Hampshire. GLIMR Instrument Operation Centers. Institute for the Study of Earth, Oceans, and Space. URL: https://eos.unh.edu/glimr/glimr-instrument/operation-centers