National Aeronautics and Space Administration
www.nasa.gov
NASA GSFC / USGS EROSwww.usgs.gov
The Thermal Infrared Sensor on the Landsat Data Continuity Mission The Thermal Infrared Sensor on the Landsat Data Continuity Mission
IGARSS, Honolulu, HI
July 27, 2010
Dennis Reuter
TIRS Instrument [email protected]
301-286-2042
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Landsat Mission HistoryLandsat Mission History
Landsat was first program proposed to monitor land surface data from space– Stimulated by recognition of successful atmospheric programs
Landsat 1 launched July 23, 1972– Originally called Earth Resources Technology Satellite (ERTS)– Visible/Near IR multispectral mapper.
Landsat 3, launched March 5, 1978, included one thermal band (10-12 mm)– Following missions also included thermal band
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LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 3
Landsat Data Continuity Mission (LDCM)Landsat Data Continuity Mission (LDCM)
LDCM is the follow-on to Landsat 7 with launch in Dec., 2012
LDCM provides data continuity with previous Landsats– Operational Land Imager (OLI)– Thermal Infrared Sensor (TIRS)
OLI is visible /NIR multispectral imager– Supplied by Ball Aerospace and Technology Corporation– Two new channels compared to previous Landsats– Based on pushbroom imaging system
LDCM originally did not include TIRS– Added to manifest, Dec 2009.
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 4
TIRS High-level Overview TIRS High-level Overview
TIRS is a two channel thermal imager providing data continuity for the Landsat thermal band.– Pushbroom imager developed by NASA/Goddard Space Flight Center – TIRS operates in concert with, but independently of, OLI.
TIRS will produce radiometrically calibrated, geo-located thermal image data– TIRS will deliver algorithms and parameters necessary to evaluate data and produce
required outputs – Final scene data generated as part of the Data Processing and Archive Segment at the
United States Geological Survey/ Earth Resources Observation and Science (EROS) facility in Sioux Falls, South Dakota.
– USGS responsible for operational algorithms– OLI and TIRS data will be merged into a single data stream.–
TIRS Delivery date is December 2011.– The TIRS delivery schedule is a significant driver of the overall TIRS development.
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 5
TIRS Science OverviewTIRS Science Overview
Landsat satellites have acquired single-band thermal images since 1978– Landsat 3 (1978 -1983 ) afforded 240 m spatial
resolution in the thermal band– Landsat 4 (1982 - 1989) and Landsat 5 (1984 -
present) afford 120 m resolution– Landsat 7 (1999 - present) affords 60 m
resolution Landsat thermal data are now used
operationally to monitor water consumption on a field-by-field basis in the U.S. West and internationally– Evapotranspiration cools vegetation (plants
“sweat”)– 120 meter resolution (or better) sufficient – Allowed by development of operational energy
balanced-based evapotranspiration models• SEBAL, METRIC
Using 120 m Landsat 5 Thermal DataCourtesy of Richard Allen, Kimberly Research and Extension Center, University of Idaho
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 6
Additional TIRS ScienceAdditional TIRS Science
Landsat thermal data are used for:• Mapping urban heat fluxes for air quality modeling (urban heat island)
• Volcanic hazard assessment, monitoring, and recovery
• Cloud detection and screening
• Mapping lake thermal plumes from power plants
• Burnt area mapping / Wildfire risk assessment
• Tracking material transport in lakes and coastal regions
• Identifying mosquito breeding areas and vector-borne illness potential
TIRS 2-Channel split window improves fidelity of surface temperatures Allows correction for atmospheric effects
(Images from D. Quattrochi)
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Example: Water Management Using Surface Energy BalanceExample: Water Management Using Surface Energy Balance
RNET = G + ET + HRNET = G + ET + H
Soil heat (G)
Sensible heat
(H)Net radiation
(RNET)
Latent heat(ET)
RNET = (SWdn – SWup) + (LWdn-LWup)RNET = (SWdn – SWup) + (LWdn-LWup)
• Net Radiation is the balance between incoming minus outgoing radiation• OLI required to calculate the SWup (short wave albedo)• TIRS data required to calculate the LWup from surface temperature
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 8
60 m Landsat False Color 8/26/2002 10:33am 1 km MODIS False Color 8/26/2002 11:02am
Landsat vs MODIS
Why use High Resolution Imagery?
Middle Rio Grande near Albuquerque
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 9
TIRS Instrument OverviewTIRS Instrument Overview
2 channel (10.8 and 12 um) thermal imaging instrument
Quantum Well Infrared Photometer (QWIP) detector/FPA built at GSFC
<120 m Ground Sample Distance (100 m nominal)
185 km ground swath (15º field of view)
Operating cadence: 70 frames per second
Pushbroom design with a precision scene select mirror to select between two full aperture calibration sources– Onboard variable temp black body and space view
Passively cooled telescope assembly operating at 185K (nominal)
Actively cooled (crycooler) FPA operating at ≤43K
Thermal stability key to radiometric stability (NEDT < 0.4 K @ 300 K)
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
TIRS OverviewTIRS Overview
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TIRS (Earthshield Stowed)
TIRS (Earthshield Deployed)
CryocoolerRadiator
TelescopeRadiator Scene Select
Mechanism
Nadir (Earth) View
SpacecraftInterface Flexures (2 of 3)
Captive EarthshieldLatch Hinge/Hinge
Dampers
Focal Plane Electronics Interconnecting
Harness Bracket
Blackbody CalRadiator
External Alignment Cube
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 11
TIRS FOVs and Telescope DetailTIRS FOVs and Telescope Detail
FPE
NadirView
TelescopeAssemblyCryocooler
Flexures(1 of 3)
Scene SelectMechanism
DeployedEarthshield
TelescopeRadiator
CryocoolerRadiator
Spaceview
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Thermal Design Provides Required StabilityThermal Design Provides Required Stability
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Thermal Zones:Warm End- Scene Select Mechanism (273-293 K)- Scene Select Mirror & Baffles (≤293K)
- Stability ±1K (35 sec)- Stability ±2K (44Min)
- Blackbody Calibrator (270 to 320K)- Stability ±0.1K (35 sec)
Cold End
- Tel Stage: Tel Assembly (185K)- Stability ±0.1K (35 sec)- Stability ±0.25K (44Min)
- Warm Stage: FPA Shroud (<100K)
- Cold Stage: FPA (<43K)- Stability ±0.01K (35 sec)- Stability ±0.02K (44 min)
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 13
FPA ArchitectureFPA Architecture
FPA
35 pixel overlapBetween SCAs
FPA has 1850 unique pixel columnsCorresponds to 185 km swath widthIn-track FOV < 5.4 degrees
Filter band locations based on FPAselection . Optimized to best regionon FPA.
Read 2 rows from each array for each filter and for dark regionCombine data on ground to get single best rowRow selection can be changed in flight
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 14
TIRS Focal PlaneTIRS Focal Plane
Picture of the FPA without the filters attached showing the 3 QWIPs in the center.
Picture of the FPA with the filters attached. Note that there are two filters over each array with a thin dark strip between them.
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
TIRS on LDCM Spacecraft TIRS on LDCM Spacecraft
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MEB
Cryocooler Electronics
Deployable Earth Shield
(Stowed)
OLI
XYZ
Sensor UnitConnector Bulkhead
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 16
Top Level Operations ConceptTop Level Operations Concept
Imaging Requirements– 400 WRS-2 scenes/24 hour period– Image up to 15 degrees off-nadir– Acquire up to 77 contiguous sun-lit scenes per orbit– Acquire up to 38 contiguous night scenes per orbit
Calibration Operations Requirements– Onboard calibration capability
Spaceview and onboard NIST Traceable Black Body– No calibration maneuvers required– No planned vicarious calibration sources
Orbit Requirements– 705 km altitude– 98.2 ± 0.015 degrees inclination– 10:00 AM equatorial crossing descending node
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Pre-Launch Calibration Performed at GSFCPre-Launch Calibration Performed at GSFC
Calibration tests are designed to understand the sensor behavior
Requirement verification is necessary but not sufficient for sensor characterization– L 4 requirements– Special Characterization Test
Requirements (SCTR)– Verify vendor-supplied test data
Calibration GSE requirements defined to satisfy calibration tests.
Calibration GSE is NIST traceable.Performance measured at component, subsystem and system level.
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Component
Acceptance andcalibration tests
System
Subsystem
Calibration/ValidationPlan
Requirements
SCTR
NIST standards
Level 4performance
Testdefinition
L4Verification Matrix
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
In Chamber Calibration EquipmentIn Chamber Calibration Equipment
16” Diameter Flood sourceTarget Source Module
– Blackbody– 16 position motorized target wheel– 8 position motorized filter Wheel
13” square steering mirror system– Linear stage expands effective
yaw range– Pitch & yaw
Folded, all reflective, off-axis parabola collimator
Linear stages to move sourcesCooled enclosure over entire system
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LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Phase 1 Calibration Equipment- Acceptance at ATK – 10/2009Phase 1 Calibration Equipment- Acceptance at ATK – 10/2009
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Phase 1 cal equipment includes 102 cm focal length OAP, blackbody, aperture wheel, filter wheel chopper, wiring and liquid N2 plumbing.
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 20
Significant TIRS Hardware on HandSignificant TIRS Hardware on Hand
Calibration GSE
EM Cryocooler
FPM Telescope
FPM FPA
EM FPE
BB SSM
LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
TIRS Status and Upcoming workTIRS Status and Upcoming workDesign Finalized for all Systems
All Major Contracts in Place
Successful CDR April 27 - 30, 2010
Schedule, While Aggressive, is Being Met• Challenges Remain• Very active management and scrutiny
Active Testing/ Measurement Campaign in Progress.
TIRS is benefitting greatly from active support of all partners• Includes NASA GSFC, LDCM, USGS, NASA HQ, Orbital Systems
(Spacecraft Provider)
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