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

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

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

Mission Scope

>5 Year Effort Public Data Conservation Education Public Outreach

• 1. Global Reef Survey -- Consistent Data Set
• 2. Temporal Reef Health Monitoring

{ Science Objectives

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

10 Meter resolution

Wavelength (nm) SeaWiFS MODIS CRSM Algal Type Photo synthetic Pigment Animal Fluorescence Interest 410 412 412 X 443 443 443 X All Chlorophyll a Absorption max 450 480-490 490 488 X Brown Fucoxanthin, Peridinin Blue-green Absorption max 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, Blue- green Phycobilins 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 minimum Chlorophyll 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

Nomenclature Cener Wavelength Full 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 µm square)

• Signal would be ≈107 photons/s/nm/pixel at

100% albedo

• Output >106 electrons/s/pixel, 10nm filter
• 1.3 ms/pixel, 96 pixels = 1.25x103 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
• f 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

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

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