ISS Utilization: ECOSTRESS (ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station)
Background: In July 2014, NASA has selected proposals from the second Earth Venture Instrument (EVI-2) Pathfinder Program for two new instruments that will observe changes in global vegetation from the International Space Station. The sensors will give scientists new ways to see how forests and ecosystems are affected by changes in climate or land use change. 1) 2) 3)
The new projects are:
• GEDI (Global Ecosystem Dynamics Investigation), a laser-based system from the University of Maryland, College Park, to observe the structure of forest canopy. This instrument is expected to be launched in 2019.
- Ralph Dubayah, of the University of Maryland, is the principal investigator for the GEDI Lidar. This project will use a laser-based system to study a range of climates, including the observation of the forest canopy structure over the tropics, and the tundra in high northern latitudes. This data will help scientists better understand the changes in natural carbon storage within the carbon cycle from both human-influenced activities and natural climate variations.
- The GEDI team has extensive experience in observing and modeling forest and vegetation dynamics. Dubayah has led numerous vegetation lidar observations from sub-orbital platforms throughout his career. The team includes partnerships with NASA's Goddard Space Flight Center, Greenbelt, Maryland; Woods Hole Research Center, Woods Hole, Massachusetts; the U.S. Forest Service, Ogden, Utah; and Brown University, Providence, Rhode Island.
• ECOSTRESS (ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station), a high-resolution multiple wavelength imaging spectrometer from NASA/JPL (Jet Propulsion Laboratory) in Pasadena, CA, to study the effectiveness of water use by vegetation.
- Simon Hook of JPL is the PI (Principal Investigator) for ECOSTRESS. This project will use a high-resolution thermal infrared radiometer to measure plant evapotranspiration, the loss of water from growing leaves and evaporation from the soil. These data will reveal how ecosystems change with climate and provide a critical link between the water cycle and effectiveness of plant growth, both natural and agricultural.
- The ECOSTRESS team has extensive experience in development and analysis of thermal infrared spectroscopic images of the Earth's surface. Hook has served as project scientist for the ASTER (Advanced Spaceborne Thermal Emission Reflection Radiometer) instrument on NASA's Earth Observing System Terra satellite and has been involved in numerous sub-orbital field campaigns. The team includes partnerships with the U.S. Department of Agriculture, Beltsville, Maryland, and Maricopa, Arizona; Princeton University, Princeton, New Jersey; and University of Idaho, Moscow, Idaho.
The International Space Station provides several in-orbit capabilities useful to both instruments. The space station orbit is inclined relative to the poles, providing more observation time of forests and vegetation over temperate land masses than possible from the polar orbits commonly used for other types of Earth observations. The GEDI laser requires significant power resources, which the space station can provide. Also, the relatively low altitude of the station's orbit, about 400 km up, benefits GEDI by ensuring a higher return energy for laser pulses reflected from the ground.
NASA/LaRC (Langley Research Center) in Hampton, Virginia, manages the Earth System Science Pathfinder program for NASA's Science Mission Directorate. The missions in this program provide an innovative approach to address Earth science research with periodic windows of opportunity to accommodate new scientific priorities.
Figure 1: Two new spaceborne Earth-observing instruments will help scientists better understand how global forests and ecosystems are affected by changes in climate and land use change. This image of the Amazon rainforest is from a 2010 global map of the height of the world's forests based on multiple satellite datasets (image credit: NASA Earth Observatory)
The NASA ECOSTRESS mission is one of two instruments chosen from the second EVI-2 (Earth Venture Instrument) Pathfinder Program AO (Announcement of Opportunity). With a launch scheduled for 2018, ECOSTRESS will assess vegetation water stress using a multispectral thermal instrument installed on the International Space Station. In the ISS orbit of ~ 400 km altitude and 51.6º inclination, ECOSTRESS will provide a repeat cycle of nearly three-days and a spatial resolution of ~ 60 m. Due to the unique orbital path of the ISS, ECOSTRESS will observe the same spot on Earth at different times each day. This configuration will enable an unprecedented view of diurnal trends in vegetation evapotranspiration, allowing the science community to address the following questions: 4) 5) 6)
• How does the terrestrial biosphere respond to changes in water availability?
• How do evapotranspiration and vegetation water stress interact with the global carbon cycle?
• How can scientists better understand agricultural vulnerabilities and drought impacts linked to vegetation water stress?
The ECOSTRESS mission will answer these questions by accurately measuring the temperature of plants. Plants regulate their temperature by releasing water through tiny pores on their leaves called stomata. If they have sufficient water they can maintain their temperature but if there is insufficient water their temperatures rise and this temperature rise can be measured with a sensor in space. ECOSTRESS will use a multispectral thermal infrared radiometer to measure the surface temperature that will be delivered to Houston for deployment on the International Space Station in 2018. The radiometer will acquire the most detailed temperature images of the surface ever acquired from space and will be able to measure the temperature of an individual farmers field.
One of the core products that will be produced by ECOSTRESS team is ESI (Evaporative Stress Index). ESI is a leading drought indicator - it can indicate that plants are stressed and that a drought is likely to occur providing the option for decision makers to take action. Figure 3 illustrates the ESI for the United States during the 2012 drought. The red areas indicate regions of high water stress.
Figure 3: Map of the 2012 drought in the United States showing differences in water stress. Red areas indicate high water stress (drought conditions) and green areas indication low water stress (non-drought conditions), image credit: NASA/JPL
Simon J. Hook of NASA/JPL is the PI of the ECOSTRESS instrument development and science investigation. The mission leverages the successful design, construction, and testing of the PHyTIR (Prototype HyspIRI Thermal Infrared Radiometer), which was initially developed to support testing and assessment for the HyspIRI (Hyperspectral Infrared Imager) under the auspices of ESTO (Earth Science Technology Office). ECOSTRESS consists of a cross-track, push-whiskbroom, scanning, multiband filter radiometer with five spectral bands between 8 and 12.5 µm, and a high spatial resolution of 38 m in-track by 69 m cross-track, and will be deployed on the JEM (Japanese Experiment Module) External Facility on the ISS. Because of the precessing orbit of the ISS, the ECOSTRESS will enable vegetation water stress assessments on a diurnal scale. 7)
The multispectral TIR (Thermal Infrared) instrument, mounted on the JEM-EF , will measure the brightness temperature of plants and use that information to better understand how much water plants need and how they respond to stress (evapotranspiration dynamics).
The ECOSTRESS instrument has a mass of ~465 kg, an average power consumption of ~527 W, a volume of 1.3 m3, an average data rate of 2.3 Mbit/s (nominally 4.5 Mbit/s) and a design life of 5 years. Typical revisit of 90% of CONUS every 4 days at varying times over the diurnal cycle.
The TIR instrument will acquire data from the ISS with a 38 m in-track by 68 m cross-track spatial resolution in five spectral bands, located in the TIR part of the electromagnetic spectrum between 8 and 12.5 µm. The positions of three of the TIR bands closely match the first three thermal bands of ASTER, while two of the TIR bands match bands of ASTER and MODIS typically used for split-window type applications (ASTER bands 12–14 and MODIS bands 31, 32). It is expected that small adjustments to the band positions will be made based on ongoing engineering filter performance capabilities. 10)
The TIR instrument will operate as a push-whisk mapper, similar to MODIS but with 256 pixels in the cross-whisk direction for each spectral channel (Figure 4), which enables a wide swath and high spatial resolution. As the ISS moves forward, the scan mirror sweeps the focal plane ground projection in the cross-track direction. Each sweep is 256-pixels wide. The different spectral bands are swept across a given point on the ground sequentially. From the 400±25 km ISS altitude, the resulting swath is 402 km wide. A wide continuous swath is produced even with an ISS yaw of up to ±18.5º. The scan mirror rotates at a constant angular speed. It sweeps the focal plane image 53º across nadir, then to two on-board blackbody targets at 300 K and 340 K. Both blackbodies will be viewed with each cross-track sweep every 1.29 seconds to provide gain and offset calibrations.
Figure 5: Drawing of the ECOSTRESS radiometer in its container (image credit: NASA/JPL)
Launch: A launch of the ECOSTRESS instrument is scheduled for June 2018 on the SpX-15 logistics flight (Dragon trunk) of SpaceX. The launch site is the Cape Canaveral Air Force Station, FL. 13)
Orbit: Near-circular orbit of the ISS, altitude of ~400 km, inclination = 51.6º, period = 93 minutes.
The ECOSTRESS instrument will be mounted onto the JEM-EF (Exposed Facility) site 10 of JAXA. At this location, the radiometer scan is perpendicular to the ISS velocity.
Figure 6: Overview of Earth science instruments on the ISS (installed or planned) in the second decade of the 21st century (image credit: NASA) 14)
In summary, ECOSTRESS will provide the highest spatial resolution thermal infrared data ever from the International Space Sta1on. HyspIRI (Hyperspectral Infrared Imager) is planned for the 2023+ timeframe.
• ECOSTRESS is possible because of the development of the PHyTIR (Prototype HyspIRI Thermal Infrared Radiometer) instrument for HyspIRI-TIR supported by ESTO
• ECOSTRESS will address a subset of the science associated with HyspIRI
• The ECOSTRESS mission will help answer three key science questions:
- How is the terrestrial biosphere responding to changes in water availability?
- How do changes in diurnal vegetation water stress impact the global carbon cycle?
- Can agricultural vulnerability be reduced through advanced monitoring of agricultural water consumptive use and improved drought es1ma1on?
• ECOSTRESS has a clearly defined set of data products and mature algorithms
• Opportunity for combined HyspIRI-like datasets using the European EnMAP and ECOSTRESS with GEDI (Global Ecosystems Dynamics Investigation Lidar) for structure.
• April 30, 2018: ORR (Operational Readiness Review) at JPL (Jet Propulsion Laboratory).
• The ECOSTRESS instrument will be shipped to the launch site at Kennedy Space Center on March 12, 2018 (Ref. 7).
• May, 2016: JPL selected an upgraded Thales LPT9310 COTS (Commercial Off The Shelf) cryocooler for the ECOSTRESS instrument. The LPT9310's proven reliability has resulted in interest from JPL in using this cooler for cost-sensitive space applications. This instrument provides nominally over 4 W of cooling capacity at 80 K. - However, this capability has only been proven in terrestrial (commercial) applications. In order to provide sufficient justification for using an off-the-shelf cooler for a flight application, additional tests have been performed on the delivered flight coolers, to attain a sufficiently controlled level of quality while leveraging the heritage of the COTS cooler. 15)
- A qualification test campaign was completed successfully, with the upgraded design meeting qualification-level robustness requirements after being subjected to fatigue cycling as well as providing the required efficiency increase. Flight models are currently in production and will be delivered to JPL July 2016.
Figure 7: Timeline of ECOSTRESS (image credit: NASA/JPL, Ref. 8)
Figure 8: Photo of the LPT9310 pulse tube cryocooler (image credit: Thales Cryogenics B. V.)
Figure 9: EM cryocooler installation for ECOSTRESS (image credit: NASA/JPL)
Figure 10: Japanese Experiment Module on International Space Station (image credit: NASA)
1) Steve Cole, "NASA Selects Instruments to Track Climate Impact on Vegetation," NASA, Release 14-199, July 30, 2014, URL: https://www.nasa.gov/press/2014/july
2) Alan Buis, "NASA's ECOSTRESS Will Monitor Plant Health," NASA, October 27, 2014, URL:
3) Lacey Young, Alan Buis, "New NASA Insights into the Secret Lives of Plants," NASA/JPL, Nov. 2017, URL: https://www.jpl.nasa.gov/news/news.php?release=2017-298
4) Christine M. Lee,Joshua B. Fisher, Simon J. Hook, "ECOSTRESS Science Team Meeting," NASA, The Earth Observer, March-April 2016, Volume 28, Issue 2, p. 24, URL:
6) Christine M. Lee,Joshua B. Fisher, Simon J. Hook, "ECOSTRESS Science Team Meeting," NASA, The Earth Observer, May-June 2015, Volume 27, Issue 3, URL:
8) Wes Schmitigal, "ECOSTRESS Payload," 2017 ECOSTRESS Science Team Meeting, 15 - 17 May 2017, URL:
9) William R. Johnson, "ECOSTRESS Instrument Performance," 2017 ECOSTRESS Science Team Meeting, 15 - 17 May 2017, URL: https://ecostress.jpl.nasa.gov/downloads
10) Glynn Hulley, Simon Hook, Joshua Fisher, Christine Lee, "ECOSTRESS, a NASA Earth-Ventures instrument for studying links between the water cycle and plant health over the diurnal cycle," Proceedings of IGARSS 2017 (IEEE International Geoscience and Remote Sensing Symposium), Fort Worth, Texas, USA, July 23–28, 2017
11) Simon J. Hook and the HyspIRI and ECOSTRESS Teams, "ECOSTRESS Update," JPL/ Caltech, June 1, 2016, URL: https://hyspiri.jpl.nasa.gov/downloads
12) Simon J. Hook and the ECOSTRESS Team, "ECOSTRESS (ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station) Overview," 2017 ECOSTRESS Science Team Meeting, 15 - 17 May 2017, URL:
13) US Commercial ELV launch manifest, 6 March 2018, URL:
14) Julie A. Robinson, William L. Stefanov,"Earth Science Research on the International Space Station," Committee on Earth Science and Applications from Space (CESAS) Space Studies Board National Academies of Science, Engineering, Medicine, 29 March 2016, URL:
15) R. Arts, J. Mullié, D. Johnson, I. McKinley, J. Rodriguez, T. Benschop, "LPT9310 COTS cooler for ECOSTRESS," ICC (International Conference on Communications), Kuala Lumpur, Malaysia, May 23-27, 2016 , URL:
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (email@example.com).