The Thermal Infrared Sensor (TIRS) on the Landsat Data Continuity Mission will provide two-channel thermal imaging to continue the thermal data record begun by previous Landsat satellites. TIRS will produce calibrated and geolocated thermal imagery at 100m spatial resolution across a 185km swath from its orbit on the Landsat spacecraft. The TIRS instrument utilizes a quantum well infrared photometer detector and pushbroom imaging design to meet calibration and operational requirements for continuity of the long-term Landsat thermal data record.

1. National Aeronautics and Space Administration
www.nasa.gov
NASA GSFC / USGS EROS
www.usgs.gov
The Thermal Infrared Sensor on the
Landsat Data Continuity Mission
IGARSS, Honolulu, HI
July 27, 2010
Dennis Reuter
TIRS Instrument Scientist
dennis.c.reuter@nasa.gov
301-286-2042

2. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Landsat 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 m)
– Following missions also included thermal band
2

3. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 3
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.

4. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 4
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.

5. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 5
TIRS 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 Data
Courtesy of Richard Allen, Kimberly Research and
Extension Center, University of Idaho

6. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 6
Additional 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)

7. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Example: Water Management Using Surface Energy Balance
RNET = G + ET + H
Soil heat (G)
Sensible heat
(H)
Net radiation
(RNET)
Latent heat
(ET)
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

8. 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

9. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 9
TIRS 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 (NE T < 0.4 K @ 300 K)

10. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
TIRS Overview
10
TIRS
(Earthshield Stowed)
TIRS
(Earthshield Deployed)
Cryocooler
Radiator
Telescope
Radiator Scene Select
Mechanism
Nadir
(Earth) View
Spacecraft
Interface Flexures
(2 of 3)
Captive
Earthshield
Latch
Hinge/Hinge
Dampers
Focal Plane
Electronics Interconnecting
Harness Bracket
Blackbody Cal
Radiator
External
Alignment Cube

11. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 11
TIRS FOVs and Telescope Detail
FPE
Nadir
View
Telescope
Assembly
Cryocooler
Flexures
(1 of 3)
Scene Select
Mechanism
Deployed
Earthshield
Telescope
Radiator
Cryocooler
Radiator
Spaceview

12. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Thermal Design Provides Required Stability
12
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)

13. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 13
FPA Architecture
FPA
35 pixel
overlap
Between SCAs
FPA has 1850 unique pixel
columns
Corresponds to 185 km swath
width
In-track FOV < 5.4 degrees
Filter band locations based on
FPA
selection . Optimized to best
region
on FPA.
Read 2 rows from each array for each filter and for
dark region
Combine data on ground to get single best row
Row selection can be changed in flight

14. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 14
TIRS 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.

15. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
TIRS on LDCM Spacecraft
15
MEB
Cryocooler Electronics
Deployable Earth
Shield
(Stowed)
OLI
X
Y
Z
Sensor Unit
Connector Bulkhead

16. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS 16
Top 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

17. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Pre-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.
17
Component
Acceptance and
calibration tests
System
Subsystem
Calibration/Validation
Plan
Requirements
SCTR
NIST standards
Level 4
performance
Test
definition
L4
Verification Matrix

18. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
In Chamber Calibration Equipment
16” Diameter Flood source
Target 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 sources
Cooled enclosure over entire system
18

19. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Phase 1 Calibration Equipment- Acceptance at
ATK – 10/2009
19
Phase 1 cal equipment includes 102 cm focal length OAP, blackbody, aperture wheel, filter
wheel chopper, wiring and liquid N2 plumbing.

20. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
Significant TIRS Hardware on Hand
Calibration GSE
EM Cryocooler
FPM Telescope
FPM FPA
EM FPE
BB SSM
20

21. LANDSAT Data Continuity Mission
NASA GSFC / USGS EROS
TIRS Status and Upcoming work
Design 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)