The Coral Reef Satellite Mission Robert F. Goeke, Member SPIE - PowerPoint PPT Presentation

The Coral Reef Satellite Mission Robert F. Goeke, Member SPIE Center for Space Research Massachusetts Institute of Technology 11th SPIE International Symposium/Remote Sensing Remote Sensing of the Ocean and Sea Ice 13-14 September 2004

Mission Motivation This set of photographs, taken from the same vantage point ten years apart, illustrates the rapid degradation of coral reefs that has occurred throughout the Florida Keys and Caribbean Sea. Carysfort Reef, the largest and most luxuriant reef in the Florida Keys, has lost over 90% of its living coral cover from pollution, disease, and physical damage since 1975 when monitoring began Why: Because there is a global ocean health problem Who: PCRF, because no government seems to care enough When: ASAP, because the crisis is already far along

Mission Scope >5 Year Effort Public Data Conservation Education Public Outreach 1. Global Reef Survey -- Consistent Data Set Science { Objectives 2. Temporal Reef Health Monitoring

Flight Segment Overview • Science Requirements: – 12 spectral bands, 10 m pixels • Observation Strategy – Sun-synchronous orbit, 10:30 am crossing • Spacecraft Bus – Standard EOS bus from Astrium • Launch – Rockot or Dnepr-1

Science Requirements Wavelength SeaWiFS MODIS CRSM Algal Photo synthetic Animal Interest (nm) Type Pigment Fluorescence 410 412 412 X 443 443 443 X All Chlorophyll a Absorption max 450 480-490 490 488 X Brown Fucoxanthin, Absorption max 10 Meter resolution Peridinin Blue-green Type 1 peak 500 Green Type 2 peak 510 510 X Blue-green Type 1 shoulder 515 Green Type 3 peak 530 531 X 540 Red, Phycobilins Blue- green 550 550 551 X CZCS hinge 570 X Red Phycobilins Absorption max 600 630 Brown Chlorophyll c Absorption max 675 670 667 X All Chlorophyll a Absorption max 683 678 X All Chlorophyll a Natural Fluorescence 690 700 X All Chlorophyll Chlorophyll minimum reflectance 765 765 765 X Atmosphere 865 865 865 X Atmosphere

Observation Strategy Altitude (km) Total Dose (Krads) SEU Rate Aperture 600 12 4.2 1 700 16 7.4 1.4 800 20 13 1.8 900 26 19 2.3 • Sun-synchronous orbit • 10:30 am local time • 450 Km drift/day

Spacecraft Require aiming 10Km x 10Km payload FOV to ± 1 Km, with knowledge to ± 100m

Science Payload Overview • 14 independent instruments – One basic design – 12 identical instruments; 2 with different optics • Benefits of independence – Reliability – Calibration – Handling • Final boresight alignment is on orbit

Instrument Nomenclature Quantity Descriptive Name 12 Picture – a monochromatic n x 1024 pixel image; 10 m resolution 1 Pan – a panchromatic n x 1024 pixel image; 5 m resolution 1 Palette – a 1024 element spectral dispersion of a central pixel Cener Full Nomenclature Wavelength Bandwidth Picture/410 410 nm 10 nm Picture/443 443 nm 10 nm Picture/485 485 nm 10 nm Picture/510 510 nm 10 nm Picture/530 530 nm 10 nm Picture/550 550 nm 10 nm Picture/570 570 nm 10 nm Picture/675 675 nm 10 nm Picture/683 683 nm 10 nm Picture/700 700 nm 10 nm Picture/765 765 nm 20 nm Picture/865 865 nm 20 nm

Picture Optics • Lens: 680 mm focal length, 85 mm aperture ( i.e.: f/8) • Focal Plane: Fairchild CCD525 (or equiv.) 2048 x 96 pixels (pixels are 13 µ m square) • Signal would be ≈ 10 7 photons/s/nm/pixel at 100% albedo • Output >10 6 electrons/s/pixel, 10nm filter • 1.3 ms/pixel, 96 pixels = 1.25x10 3 electrons • 0.1% measurement requires 30 e - rms

Picture Electronics • Front end: 2 CDS video chains, 12 bit A/D • Single FPGA for control – Accept CCSDS command packets – Control sampling rate, # of integrating pixels – Generate CCSDS telemetry packets – Generate engineering data telemetry packets • Data rate: 10 Mbps with no compression – NB: typically, 1 reef -> 10 sq. km -> 1 sec.

Pan Instrument • 1024 5x5 meter pixels, full visible spectrum • Optics: twice the aperture and focal length of Picture : focal length 1360mm • 300 nm bandwidth • Identical electronics running at twice the data rate of Picture • 15 times more signal than Picture will require shorter integration time.

Palette Instrument • 1 10x10 meter pixel, 2 nm resolution • Same optics as Picture instrument • Spectral dispersion of image => 1024 pixels • On-chip sum of 6 pixels to boost signal (though S/N will be 4x worse than Picture) • Identical electronics running at one quarter the date rate of Picture.

Accomodation Summary Resource Requirement Mass 75 Kg Power 75 Watts orbital average 250 Watts peak Thermal Radiator at -40C Data 150 Mbps acquisition 1 GB/day downlink

Acknowledgements The major players: Planetary Coral Reef Foundation MIT Center for Space Research EADS/Astrium, Friedrichshafen The contributing players: College of Charleston General Dynamics Scripps Institution of Oceanography SeaSpace Corporation Stevens Institute of Technology Sound Seas University of Southern California