TU2.L10.1 - THE THERMAL INFRARED SENSOR ON THE LANDSAT DATA CONTINUITY MISSION

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

mailto:[email protected]

https://secureworkgroups.grc.nasa.gov/community/content/wireframe.jsp?cid=586&uid=2F9FCE7B499F7C0F30C3C0922B8363BF&action=view&sub=wireframe&tool=files&folder_id=63489&content=file&content_id=413734&content_data_id=422720&filename=2010_13_April+SEoverview.ppt.preview.html&str_extension=ppt&preview=1&popup=1

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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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.



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.



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



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)



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



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



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)



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



TIRS FOVs and Telescope DetailTIRS FOVs and Telescope Detail

FPE

NadirView

TelescopeAssemblyCryocooler

Flexures(1 of 3)

Scene SelectMechanism

DeployedEarthshield

TelescopeRadiator

CryocoolerRadiator

Spaceview



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)



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



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.



TIRS on LDCM Spacecraft TIRS on LDCM Spacecraft

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MEB

Cryocooler Electronics

Deployable Earth Shield

(Stowed)

OLI

XYZ

Sensor UnitConnector Bulkhead



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



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



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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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.



Significant TIRS Hardware on HandSignificant TIRS Hardware on Hand

Calibration GSE

EM Cryocooler

FPM Telescope

FPM FPA

EM FPE

BB SSM



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)

Documents

TU2.L10.1 - THE THERMAL INFRARED SENSOR ON THE LANDSAT DATA CONTINUITY MISSION