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NASA NTRS2022

Surface Biology and Geology (SBG) Thermal Infrared (TIR) Free -Flyer Concept

Scientists and engineers from the United States and Italy are developing a thermal infrared (TIR) free-flyer concept that forms an essential element of the NASA Surface Biology & Geology (SBG) designated observable and the greater NASA Earth System Observatory (ESO), which also includes observations of aerosols, clouds, convection, and precipitation; mass change; and surface deformation & change.In response to the recommendations from the 2017 National Academies decadal survey for Earth science, NASA initiated the SBG designated observable with five key research and applications focus areas: ecosystems and natural resources, hydrology, weather, climate, and solid Earth. SBG includes spaceborne measurements of hyperspectral imagery in the visible to shortwave infrared (0.4-2.5 um) and multispectral imagery in the mid and thermal infrared (3-12 um) that provide the remote sensing data needed to inform each research and applications area. High-level TIR data products include Earth surface temperature & emissivity, evapotranspiration, substrate composition, volcanic plumes, and high-temperature features. While the science, applications, and technology build on prior mission studies conducted for more than a decade, it has only been recently that a joint team of scientists and engineers from the NASA Jet Propulsion Laboratory (JPL), Agenzia Spaziale Italiana (ASI), Istituto Nazionale Geofisica e Volcanologia (INGV), and the Istituto Nazionale Astrofisica (INAF) have developed a compelling concept for a TIR free-flyer. In this concept, the TIR instrument is an eight-band radiometer. Seven of the bands are between 3 and 12 um with an additional band at 1.65 um. The instrument’s 68.8 deg total viewing angle and the free-flyer’s 665 km operational altitude results in a ground sampling distance (GSD) of <60 m at nadir, produces a swath width of 935 km, and allows for a 2-3-day revisit time. A two-band visible and near infrared (VNIR) camera, with <30 m GSD at nadir and 935 km swath width, will complement the TIR instrument. VNIR high-level data products include top & bottom of atmosphere reflectance and normalized difference vegetation indices (NDVI). The TIR instrument and VNIR camera will be mounted on a PLATiNO+ spacecraft, a multi-application, reconfigurable, and scalable platform. The launcher selected for the TIR free-flyer is the VEGA-C. To maximize the science and applications benefits the SBG-TIR free-flyer team are collaborating with personnel from the ESA Land Surface Temperature Monitoring mission (LSTM) as well individuals from the Thermal Infrared Imaging Satellite for High-resolution Natural resource Assessment (TRISHNA), a joint mission by CNES and ISRO. Pre-Phase A concept studies for the SBG-TIR free-flyer commenced in the spring 2021. This allows for the concept to be refined; for technical risks to be identified and mitigated, as necessary; and strategies for reducing the development schedule to be defined and assessed before conducting a NASA-ASI Mission Concept Review (MCR) in the spring of 2022 and a NASA Key Decision Point-A (KDP-A) as early as the summer of 2022. These are key milestones in being able to launch and begin operating the SBG-TIR free-flyer in the second half of the decade, so that many of the questions posed by the National Academies in the 2017 decadal survey can be answered.

Fabrizia-Buongiorno, Maria↗
NASA NTRS2018

Landsat 9 TIRS-2 Performance Results Based on Subsystem-Level Testing

Landsat 9 is the next in the series of Landsat satellites and has a complement of two pushbroom imagers: Operational Land Imager-2 (OLI-2) that samples the solar reflective spectrum with nine channels and Thermal Infrared Sensor-2 (TIRS-2) samples the thermal infrared spectrum with two channels. The first builds of these sensors, OLI and TIRS, were launched on Landsat 8 in 2013 and Landsat 9 is expected to launch in December 2020. TIRS-2 is designed and built to continue the Landsat data record and satisfy the needs of the remote sensing community. There are two sets of requirements considered for planning the component, subsystem and instrument level tests for TIRS-2: performance requirements and Special Calibration Test Requirements (SCTR). The performance requirements specify key spectral, spatial, radiometric, and operational parameters of TIRS-2 while the SCTRs specify parameters of how the instrument is tested. Several requirements can only be verified at the instrument level, but many performance metrics can be assessed earlier in prelaunch testing at the subsystem level. A test program called TIRS Imaging Performance and Cryoshell Evaluation (TIPCE) was developed to characterize TIRS-2 spectral, spatial, and scattered-light rejection performance at the telescope and detector subsystem level. There were three thermal vacuum campaigns in TIPCE that occurred from November 2017 to March 2018. This work shows results of TIPCE data analysis which provide confidence that key requirements will be met at instrument level with a few minor waivers. A full complement of performance testing will be done at the TIRS-2 instrument level for final verification in late 2018 through Spring 2019.

scatter↗
NASA NTRS2018

An Initial Assessment of a SMAP Soil Moisture Disaggregation Scheme Using TIR Surface Evaporation Data over the Continental United States

The Soil Moisture Active Passive (SMAP) mission is dedicated toward global soil moisture mapping. Typically, an L-band microwave radiometer has spatial resolution on the order of 36-40 km, which is too coarse for many specific hydro-meteorological and agricultural applications. With the failure of the SMAP active radar within three months of becoming operational, an intermediate (9-km) and finer (3-km) scale soil moisture product solely from the SMAP mission is no longer possible. Therefore, the focus of this study is a disaggregation of the 36-km resolution SMAP passive-only surface soil moisture (SSM) using the Soil Evaporative Efficiency (SEE) approach to spatial scales of 3-km and 9-km. The SEE was computed using thermal-infrared (TIR) estimation of surface evaporation over Continental U.S. (CONUS). The disaggregation results were compared with the 3 months of SMAP-Active (SMAP-A) and Active/Passive (AP) products, while comparisons with SMAP-Enhanced (SMAP-E), SMAP-Passive (SMAP-P), as well as with more than 180 Soil Climate Analysis Network (SCAN) stations across CONUS were performed for a 19 month period. At the 9-km spatial scale, the TIR-Downscaled data correlated strongly with the SMAP-E SSM both spatially (r = 0.90) and temporally (r = 0.87). In comparison with SCAN observations, overall correlations of 0.49 and 0.47; bias of −0.022 and −0.019 and unbiased RMSD of 0.105 and 0.100 were found for SMAP-E and TIR-Downscaled SSM across the Continental U.S., respectively. At 3-km scale, TIR-Downscaled and SMAP-A had a mean temporal correlation of only 0.27. In terms of gain statistics, the highest percentage of SCAN sites with positive gains (>55%) was observed with the TIR-Downscaled SSM at 9-km. Overall, the TIR-based downscaled SSM showed strong correspondence with SMAP-E; compared to SCAN, and overall both SMAP-E and TIR-Downscaled performed similarly, however, gain statistics show that TIR-Downscaled SSM slightly outperformed SMAP-E.

Disaggregation↗
NASA NTRS2011

The Preflight Calibration of the Thermal Infrared Sensor (TIRS) on the Landsat Data Continuity Mission

The preflight calibration testing of TIRS evaluates the performance of the instrument at the component, subsystem and system level, The overall objective is to provide an instrument that is well calibrated and well characterized with specification compliant data that will ensure the data continuity of Landsat from the previous missions to the LDCM, The TIRS flight build unit and the flight instrument were assessed through a series of calibration tests at NASA Goddard Space Flight Center. Instrument-level requirements played a strong role in defining the test equipment and procedures used for the calibration in the thermal/vacuum chamber. The calibration ground support equipment (CGSE), manufactured by MEI and ATK Corporation, was used to measure the optical, radiometric and geometric characteristics of TIRS, The CGSE operates in three test configurations: GeoRad (geometric, radiometric and spatial), flood source and spectral, TIRS was evaluated though the following tests: bright target recovery, radiometry, spectral response, spatial shape, scatter, stray light, focus, and uniformity, Data were obtained for the instrument and various subsystems under conditions simulating those on orbit In the spectral configuration, a monochromator system with a blackbody source is used for in-band and out-of-band relative spectral response characterization, In the flood source configuration the entire focal plane array is illuminated simultaneously to investigate pixel-to-pixel uniformity and dead or inoperable pixels, The remaining tests were executed in the GeoRad configuration and use a NIST calibrated cavity blackbody source, The NIST calibration is transferred to the TIRS sensor and to the blackbody source on-board TIRS, The onboard calibrator will be the primary calibration source for the TIRS sensor on orbit.

Smith, Ramsey↗
NASA NTRS2012

Simulation of Image Performance Characteristics of the Landsat Data Continuity Mission (LDCM) Thermal Infrared Sensor (TIRS)

The next Landsat satellite, which is scheduled for launch in early 2013, will carry two instruments: the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). Significant design changes over previous Landsat instruments have been made to these sensors to potentially enhance the quality of Landsat image data. TIRS, which is the focus of this study, is a dual-band instrument that uses a push-broom style architecture to collect data. To help understand the impact of design trades during instrument build, an effort was initiated to model TIRS imagery. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool was used to produce synthetic "on-orbit" TIRS data with detailed radiometric, geometric, and digital image characteristics. This work presents several studies that used DIRSIG simulated TIRS data to test the impact of engineering performance data on image quality in an effort to determine if the image data meet specifications or, in the event that they do not, to determine if the resulting image data are still acceptable.

Landsat↗
NASA NTRS2018

Landsat 9 TIRS-2 Architecture and Design

TIRS-2 will fly on the LandSat 9. Like TIRS on Landsat 8, TIRS-2 will produce radiometrically calibrated, geo-located thermal image data. USGS is responsible for operational code. TIRS-2 image data will have the same performance characteristics as that of TIRS on Landsat 8 except better in some cases.

Thermal↗
NASA NTRS2002

Arc Jet Testing of the TIRS Cover Thermal Protection System for Mars Exploration Rover

This paper summarizes the arc jet test results of the Mars Exploration Rover (MER) Silicone Impregnated Reusable Ceramic Ablator (SIRCA) Transverse Impulse Rocket System (TIRS) Cover test series in the Panel Test Facility (PTF) at NASA Ames Research Center (ARC). NASA ARC performed aerothermal environment analyses, TPS sizing and thermal response analyses, and arc jet testing to evaluate the MER SIRCA TIRS Cover design and interface to the aeroshell structure. The primary objective of this arc jet test series was to evaluate specific design details of the SIRCA TIRS Cover interface to the MER aeroshell under simulated atmospheric entry heating conditions. Four test articles were tested in an arc jet environment with various sea] configurations. The test condition was designed to match the predicted peak flight heat load at the gap region between the SIRCA and the backshell TPS material, SLA-561S, and resulted in an over-test (with respect to heat flux and heat load) for the apex region of the SIRCA TIRS Cover. The resulting pressure differential was as much as twenty times that predicted for the flight case, depending on the location, and there was no post-test visual evidence of over-heating or damage to the seal, bracket, or backshell structure. The exposed titanium bolts were in good condition at post-test and showed only a small amount of oxidation at the leading edge locations. Repeatable thermocouple data were obtained and SIRCA thermal response analyses were compared to applicable thermocouple data. For the apex region of the SIRCA TIRS Cover, a one-dimensional thermal response prediction proved overly conservative, as there were strong multi-dimensional conduction effects evident from the thermocouple data. The one-dimensional thermal response prediction compared well with the thermocouple data for the leading edge "lip" region at the bolt location. In general, the test results yield confidence in the baseline seal design to prevent hot gas ingestion at the bracket and composite aeroshell structure interface.

Szalai, Christine E.↗
NASA NTRS2011

The Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS) on the Landsat Data Continuity Mission (LDCM)

The Landsat Data Continuity Mission (LDCM), a joint NASA and United States Geological Survey (USGS) mission, is scheduled for launch in December, 2012. The LDCM instrument payload will consist of the Operational Land Imager (OLI), provided by Ball Aerospace and Technology Corporation (BATC) under contract to NASA and the Thermal Infrared Sensor (TIRS), provided by NASA's Goddard Space Flight Center (GSFC). This paper will describe the design, capabilities and status of the OLI and TIRS instruments. The OLI will provide 8 channel multispectral images at a spatial resolution of 30 meters and panchromatic images at 15 meter spatial resolution. The TIRS is a 100 meter spatial resolution push-broom imager whose two spectral channels, centered at 10.8 and 12 microns, split the ETM+ thermal bands. The two channels allow the use of the "split-window" technique to aid in atmospheric correction. The TIRS focal plane consists of three Quantum Well Infrared Photodetector (QWIP) arrays to span the 185 km swath width. The OLI and TIRS instruments will be operated independently but in concert with each other. Data from both instruments will be merged into a single data stream at the (USGS)/Earth Resources Observation and Science (EROS) facility. The ground system, being developed by USGS, includes an Image Assessment System (lAS), similar to Landsat-7's, to operationally monitor, characterize and update the calibrations of the two sensors.

Reuter, Dennis↗
NASA NTRS2014

Landsat-8 Thermal Infrared Sensor (TIRS) Vicarious Radiometric Calibration

Launched in February 2013, the Landsat-8 carries on-board the Thermal Infrared Sensor (TIRS), a two-band thermal pushbroom imager, to maintain the thermal imaging capability of the Landsat program. The TIRS bands are centered at roughly 10.9 and 12 micrometers (Bands 10 and 11 respectively). They have 100 m spatial resolution and image coincidently with the Operational Land Imager (OLI), also on-board Landsat-8. The TIRS instrument has an internal calibration system consisting of a variable temperature blackbody and a special viewport with which it can see deep space; a two point calibration can be performed twice an orbit. Immediately after launch, a rigorous vicarious calibration program was started to validate the absolute calibration of the system. The two vicarious calibration teams, NASA/Jet Propulsion Laboratory (JPL) and the Rochester Institute of Technology (RIT), both make use of buoys deployed on large water bodies as the primary monitoring technique. RIT took advantage of cross-calibration opportunity soon after launch when Landsat-8 and Landsat-7 were imaging the same targets within a few minutes of each other to perform a validation of the absolute calibration. Terra MODIS is also being used for regular monitoring of the TIRS absolute calibration. The buoy initial results showed a large error in both bands, 0.29 and 0.51 W/sq m·sr·micrometers or -2.1 K and -4.4 K at 300 K in Band 10 and 11 respectively, where TIRS data was too hot. A calibration update was recommended for both bands to correct for a bias error and was implemented on 3 February 2014 in the USGS/EROS processing system, but the residual variability is still larger than desired for both bands (0.12 and 0.2 W/sq m·sr·micrometers or 0.87 and 1.67 K at 300 K). Additional work has uncovered the source of the calibration error: out-of-field stray light. While analysis continues to characterize the stray light contribution, the vicarious calibration work proceeds. The additional data have not changed the statistical assessment but indicate that the correction (particularly in band 11) is probably only valid for a subset of data. While the stray light effect is small enough in Band 10 to make the data useful across a wide array of applications, the effect in Band 11 is larger and the vicarious results suggest that Band 11 data should not be used where absolute calibration is required.

TIIRS↗
NASA NTRS2012

HyspIRI Thermal Infrared (TIR) Band Study Report

One of the many science questions that will be addressed by the Hyperspectral Infrared Imager (HyspIRI) mission will be to help identify natural hazards such as volcanic eruptions and any associated precursor activity, and it will also map the mineralogical composition of the land surface. To answer these questions, the HyspIRI satellite includes a thermal infrared (TIR) multispectral scanner with seven spectral bands in the thermal infrared (TIR) between 7 and 12 µm and one band in the mid-infrared between 3 and 5 µm designed to measure hot targets. The TIR bands have a NEΔT of <0.2 K at 300K and all bands have a spatial scale of 60 m. A critical aspect of HyspIRI being successful at answering these science questions is placement of the 7 TIR bands in the 7-12 µm spectral region. In order to help determine the optimum positions for the TIR bands, a small team was assembled to conduct a study report based on laboratory, spaceborne and airborne data.

Ramsey, M.↗
NASA NTRS2020

Landsat-8 TIRS Thermal Radiometric Calibration Status

The Landsat-8 Thermal Infrared Sensor (TIRS) has been acquiring two-band thermal infrared images of the Earth’s surface since 2013. The calibration of the two-band system has been monitored using the on-board calibrator and validated with vicarious calibration performed by NASA/JPL and RIT since launch. Soon after launch, it was discovered that the instrument had a significant stray light effect that was affecting the radiometric calibration. The stray light was corrected in the processing system in 2017. Since then, it has become apparent that there was an additional radiometric error, based on the vicarious calibration results. With a failure within the primary electronic system and subsequent switch to the redundant electronic system, the TIRS instrument effectively has two separate calibration regimes. The vicarious calibration found a statistically significant calibration error, primarily a constant over time, in Band 11 on the primary electronics (Feb 11,2013 through March 5,2015) of about -0.6K at 300K. The calibration error in Band 10 was smaller though still statistically significant at about 0.2K at 300K. On the redundant side(March 5,2015 to present), the calibration error is more signal dependent than time dependent. Both bands are affected, with Band 10 having an error between 1K and -0.4K (between 273-320K) and Band 11 having an error between 0.8K and -1.44K (between 273-320K).This calibration error will be corrected within the USGS Landsat Product Generation System with the release of Landsat Collection-2 products. The Collection-2 release also includes a correction to the relative radiometric calibration of TIRS data. Striping as a result of poor detector-to-detector normalization has been increasing in the imagery since launch. The TIRS relative radiometric calibration will be updated based on internal calibrator data to remove the stripes on a quarterly basis. The visible stripes are generally at 0.1-0.2% level, though there are some detectors in each band that have changed by 1% or more. The Collection-2 release will result in much more uniform TIRS images.

Julia A Barsi↗
NASA NTRS2005

The Mars Exploration Rover (MER) Transverse Impulse Rocket System (TIRS)

In a very short period of time the MER project successfully developed and tested a system, TIRS/DIMES, to improve the probability of success in the presence of large Martian winds. The successful development of TIRS/DIMES played a big role in the landing site selection process by enabling the landing of Spirit on Gusev crater, a site of very high scientific interest but with known high wind conditions. The performance of TIRS by Spirit at Gusev Crater was excellent. The velocity prediction error was small and Big TIRS was fired reducing the impact horizontal velocity from approximately 23 meters per second to approximately 11 meters per second, well within the airbag capabilities. The performance of TIRS by Opportunity at Meridiani was good. The velocity prediction error was rather large (approximately 6 meters per second, a less than 2 sigma value, but TIRS did not fire which was the correct action.

Transverse Impulse Rocket System (TIRS)↗
NASA NTRS2009

Terrestrial Applications of the Thermal Infrared Sensor, TIRS

Landsat satellites have acquired single-band thermal images since 1978. The next satellile in the heritage, Landsat Data Continuity Mission (LDCM), is scheduled to launch in December 2012. LDCM will contain the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS), where TIRS operates in concert with, but independently of OLI. This paper will provide an overview of the remote sensing instrument TIRS. The T1RS instrument was designed at National Aeronautics and Space Administration's (NASA) Goddard Space Flight Center (GSFC) where it will be fabricated and calibrated as well. Protecting the integrity of the Scientific Data that will be collected from TIRS played a strong role in definition of the calibration test equipment and procedures used for the optical, radiometric, and spatial calibration. The data that will be produced from LCDM will continue to be used world wide for environment monitoring and resource management.

Smith, Ramsey L.↗
NASA NTRS2011

High Speed, Multi-Channel, Thermal Instrument Development in Support of HyspIRI-TIR

The Jet Propulsion Laboratory is currently developing an end-to-end instrument which will provide a proof of concept prototype vehicle for a high data rate, multi-channel, thermal instrument in support of the Hyperspectral Infrared Imager (HyspIRI)-Thermal Infrared (TIR) space mission. HyspIRI mission was recommended by the National Research Council Decadal Survey (DS). The HyspIRI mission includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. The prototype testbed instrument addressed in this effort will only support the TIR. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. Current designs for the HyspIRI-TIR space borne imager utilize eight spectral bands delineated with filters. The system will have 60m ground resolution, 200mK NEDT, 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. The prototype instrument will use mercury cadmium telluride (MCT) technology at the focal plane array in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence high data rates needed for the 5 day repeat. The current HyspIRI requirements dictate a ground knowledge measurement of 30m, so the prototype instrument will tackle this problem with a newly developed interferometeric metrology system. This will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing postprocessing (e.g. geo-rectification computations).

Multi-spectral↗
NASA NTRS2013

Thermal Infrared Sensor (TIRS) Instrument Thermal Subsystem Design and Lessons Learned

The Thermal Infrared Sensor (TIRS) is one of two instruments on the Landsat Data Continuity Mission (LDCM), which is scheduled to launch in February of 2013. The TIRS instrument was officially added to the mission later in the flow, which led to a highly aggressive schedule that became one of the main drivers during instrument development. The thermal subsystem design of the TIRS Sensor Unit is comprised of five thermal zones which range in temperature from less than 43 Kelvin to 330 Kelvin. Most zones are proportional heater controlled, and all are within a volume of 35 cu.ft. A two-stage cryocooler is used to cool the "cold stage" including three QWIP detectors to less than 43 Kelvin, and cool the "warm stage" to 105 Kelvin. The excess power dissipation from the cryocooler is rejected via ammonia transport heat pipes to a dedicated Cryocooler Radiator with embedded ammonia heat pipes. The cryogenic subsystem includes a series of shells used to radiatively and conductively isolate the cold stage from the warmer surroundings. The Optical System (telescope) is passively cooled to 180-190 Kelvin using a "thermal link" (comprised of a Flexible Conductive Thermal Strap and an APG Bar) which couples the telescope stage to a dedicated radiator with embedded ethane heat pipes. The Scene Select Mechanism, which is responsible for moving the Scene Select Mirror to three distinct positions (including Nadir, Space, and On-board Black Body Calibrator pointing), runs nominally at 278 Kelvin and is thermally isolated from the cryogenic thermal zones. The On-board Black Body Calibrator requires a dedicated radiator which allows for a temperature range of 260-330 Kelvin at the Source. The detectors are powered by the FPE Box, which is mounted to the nadir external surface of the composite honeycomb structure. There are two additional electronics boxes which are wet-mounted directly to the spacecraft shear panel, the Main Electronics Box and Cryocooler Electronics Box; thermal control of these boxes is the responsibility of Orbital Sciences Corporation, the spacecraft developer. The TIRS thermal subsystem design was successfully verified during months of testing campaign, from component & subsystem level to two instrument-level thermal vacuum tests. The Instrument, despite an aggressive schedule, was delivered to the spacecraft vendor in February of 2012 and is currently undergoing the final stages of spacecraft environmental testing in preparation for launch.

Otero, Veronica↗
NASA NTRS2022

Thermal Design of the Thermal Infrared Spectrometer (TIRS) Instrument on PREFIRE

The Polar Radiant Energy in the Far-Infrared Experiment (PREFIRE) consists of two 6U CubeSats that each host a Thermal Infrared Spectrometer (TIRS) instrument. The CubeSats are scheduled for launch in March and October of 2023. The purpose of the TIRS instrument is to make spectrally resolved measurements of the Earth’s thermal radiation from the top of the atmosphere. PREFIRE will document, for the first time, variability in spectral fluxes from 4 to 54 microns on hourly to seasonal timescales. The primary mission is 12 months in a polar orbit with inclination of 82 to 98 at altitudes between 450 km and 650 km. The TIRS instrument is an Offner spectrometer that uses a thermopile detector array and a Schwarzchild telescope. In addition, there is a scan mirror which is periodically actuated for calibration. The instrument concept of operation is to collect radiation emitted towards zenith in a nadir sounding orientation with periodic internal and space calibrations. The TIRS thermal control architecture consists of entirely passive elements. The instrument requires all elements be maintained between 0 C and 50 C during operation for the duration of the mission. An overview of the overall thermal control design approach is presented.

Andrade, Andres↗
NASA NTRS2005

Monitoring Eruptive Activity at Mount St. Helens with TIR Image Data

Thermal infrared (TIR) data from the MASTER airborne imaging spectrometer were acquired over Mount St. Helens in Sept and Oct, 2004, before and after the onset of recent eruptive activity. Pre-eruption data showed no measurable increase in surface temperatures before the first phreatic eruption on Oct 1. MASTER data acquired during the initial eruptive episode on Oct 14 showed maximum temperatures of similar to approximately 330 C and TIR data acquired concurrently from a Forward Looking Infrared (FLIR) camera showed maximum temperatures similar to approximately 675 C, in narrow (approximately 1-m) fractures of molten rock on a new resurgent dome. MASTER and FLIR thermal flux calculations indicated a radiative cooling rate of approximately 714 J/m(exp 2)/s over the new dome, corresponding to a radiant power of approximately 24 MW. MASTER data indicated the new dome was dacitic in composition, and digital elevation data derived from LIDAR acquired concurrently with MASTER showed that the dome growth correlated with the areas of elevated temperatures. Low SO2 concentrations in the plume combined with sub-optimal viewing conditions prohibited quantitative measurement of plume SO2. The results demonstrate that airborne TIR data can provide information on the temperature of both the surface and plume and the composition of new lava during eruptive episodes. Given sufficient resources, the airborne instrumentation could be deployed rapidly to a newly-awakening volcano and provide a means for remote volcano monitoring.

thermal emissions↗
NASA NTRS2011

The Prototype HyspIRI Thermal Infrared Radiometer (PHyTIR): A High Speed, Multispectral, Thermal Instrument Development in Support of HyspIRI-TIR

The Prototype HyspIRI Thermal Infrared Radiometer (PHyTIR) is being developed as part of the risk reduction activities associated with the Hyperspectral Infrared Imager (HyspIRI). The HyspIRI mission was recommended by the National Research Council Decadal Survey and includes a visible shortwave infrared (SWIR) pushboom spectrometer and a multispectral whiskbroom thermal infrared (TIR) imager. Data from the HyspIRI mission will be used to address key science questions related to the Solid Earth and Carbon Cycle and Ecosystems focus areas of the NASA Science Mission Directorate. The HyspIRI TIR system will have 60m ground resolution, better than 200mK noise equivalent delta temperature (NEDT), 0.5C absolute temperature resolution with a 5-day repeat from LEO orbit. PHyTIR addresses the technology readiness level (TRL) of certain key subsystems of the TIR imager, primarily the detector assembly and scanning mechanism. PHyTIR will use Mercury Cadmium Telluride (MCT) technology at the focal plane and operate in time delay integration mode. A custom read out integrated circuit (ROIC) will provide the high speed readout hence allowing the high data rates needed for the 5 day repeat. PHyTIR will also demonstrate a newly developed interferometeric metrology system. This system will provide an absolute measurement of the scanning mirror to an order of magnitude better than conventional optical encoders. This will minimize the reliance on ground control points hence minimizing post-processing (e.g. geo-rectification computations).

National Research Council Decadal Survey↗