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How to Understand Your Child’s Screenings for Autism and Other Conditions
The predictive value of childhood screenings for autism and other conditions depends on how common the condition is, a limit that parents need to understand
Station Science Top News: September 13, 2024
JAXA (Japan Aerospace Exploration Agency) researchers examined the structures of four titanium-based compounds solidified in levitators in microgravity and on the ground and found that the internal microstructures were generally similar. These results could support development of new materials for use in space manufacturing.
To produce glass or metal alloys on Earth, raw materials are placed into a container and heated. But reactions between the container and the materials can cause imperfections. The JAXA Electrostatic Levitation Furnace can levitate, melt, and solidify materials without a container. The facility enables measurement of the thermophysical properties of high temperature melts and could accelerate development of innovative materials such as heat resistant ceramics for use in the aerospace and energy industries.
JAXA (Japan Aerospace Exploration Agency) astronaut Akihiko Hoshide works with the Electrostatic Levitation Furnace.European Space Agency/Thomas Pesquet
Satellite 3D imaging of a Peruvian tropical forest demonstrated that measuring leaf traits with remote sensing may provide more accurate predictions of biomass production than structure data such as tree height. Carbon stored or sequestered in forests can help offset emissions that cause climate change, and improved estimates of tropical forest biomass could allow researchers to better evaluate these ecosystems and their offset contributions.
Global Ecosystem Dynamics Investigation (GEDI) provides high-resolution global observations of Earth’s forests and topography. These observations provide information on carbon and water cycling processes, biodiversity, and habitat, including quantifying carbon stored in vegetation and the potential for future carbon storage. The researchers suggest that estimates of tropical forest biomass could be further improved with data from new satellite missions and by integrating GEDI with dynamic vegetation models that include trait data.
Learn more from this video and this article.
The refrigerator-sized Global Ecosystem Dynamics Investigation instrument on the exterior of the International Space Station. NASA/Nick Hague
Research indicates that refractive eye surgery is safe, effective, and suitable for astronauts. The study documented stable vision in two astronauts who, a few years prior to flight, underwent photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK), respectively. These visual correction procedures can reduce the logistical complications of wearing glasses or contact lenses in space.
International Space Station Medical Monitoring collects health data from crew members before, during, and after spaceflight. The medical evaluation requirements, including vision assessment, apply to all crew members and are part of efforts by all international partners to maintain crew health, ensure mission success, and enable crew members to return to normal life on Earth after their missions.
NASA astronauts Terry Virts (bottom) and Scott Kelly (top) perform eye exams as part of ongoing studies into crew vision health. NASA
JAXA researchers report that accurately assessing the velocity of airflow in front of a spreading flame makes it possible to predict the flammability of thin, flat materials in microgravity. These results mean it could be possible to use ground tests to predict the flammability of solid materials and thus ensure fire safety in spacecraft and space habitations.
The JAXA Fundamental Research on International Standard of Fire Safety in Space – Base for Safety of Future Manned Missions (FLARE) investigation tested the flammability of various solid materials in different configurations, including filter paper. Microgravity significantly affects combustion phenomena such as the spread of flame over solid materials; while flames cannot spread over solid materials under low-speed oxygen flow in Earth’s gravity, they can in microgravity due to the lack of buoyancy. Testing of the flammability of materials for spacecraft previously has not considered the effect of gravity, and results from this investigation could address this issue, significantly improving fire safety on future exploration missions.
JAXA astronaut Satoshi Furukawa sets up hardware for the Fundamental Research on International Standard of Fire Safety in Space – Base for Safety of Future Manned Missions investigation. NASA/Jasmin Moghbeli
Ottawa’s Fall Rhapsody
Ottawa’s Fall Rhapsody
An astronaut aboard the International Space Station captured this view of peak fall foliage around Ottawa, Canada on Oct. 14, 2020. Sugar maple leaves turn orange-red, and hickories turn golden-bronze during autumn, regionally known as “the Fall Rhapsody.”
Fall color reaches its peak when air temperatures drop and shortened daylight triggers plants to slow and stop the production of chlorophyll—the molecule that plants use to synthesize food. When the green chlorophyll pigment fades, various yellow and red pigments become visible.
Image credit: NASA EUSO
The Brain Really Does Choke Under Pressure
Study links choking under pressure to the brain region that controls movement
Going Back-to-School with NASA Data
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)As students head back to school, teachers have a new tool that brings NASA satellite data down to their earthly classrooms.
The My NASA Data homepage categorizes content by areas of study called spheres and also Earth as a system. NASA/mynasadata.larc.nasa.gov
For over 50 years of observing Earth, NASA’s satellites have collected petabytes of global science data (that’s millions and millions of gigabytes) – with terabytes more coming in by the day. Since 2004, the My NASA Data website has been developing ways for students and teachers of grades 3-12 to understand, and visualize NASA data, and to help incorporate those measurements into practical science lessons.
“We have three different types of lesson plans, some of which are student-facing and some are teacher-facing,” said Angie Rizzi, My NASA Data task lead, based at NASA’s Langley Research Center in Hampton, Virginia. “Teachers can download complete lesson plans or display a wide variety of Earth data. There are also lessons written for students to interact with directly.”
An image from My NASA Data’s Earth System Data Explorer visualization tool showing the monthly leaf index around the world as measured by NASA satellites in August 2020. Data parameters for this visualization were set to biosphere under the sphere dropdown and vegetation as a category. NASA/mynasadata.larc.nasa.gov
A key component of the My NASA Data site is the newly updated Earth System Data Explorer visualization tool, which allows users to access and download NASA Earth data. Educators can explore the data then create custom data tables, graphs, and plots to help students visualize the data. Students can create and investigate comparisons between land surface temperatures, cloud cover, extreme heat, and a wide range of other characteristics for a specific location or region around the globe.
An image from My NASA Data’s visualization tool showing various searchable categories under the atmosphere dataset selection. NASA/mynasadata.larc.nasa.gov
“The Earth System Data Explorer tool has a collection of science datasets organized by different spheres of the Earth system,” explained Desiray Wilson, My NASA Data scientific programmer. The program highlights six areas of study: atmosphere, biosphere, cryosphere, geosphere, hydrosphere, and Earth as a system. “The data goes as far back as the 1980s, and we are getting more daily datasets. It’s really good for looking at historical trends, regional trends, and patterns.”
My NASA Data had over one million site visits last year, with some of the most popular searches focusing on temperatures, precipitation, water vapor, and air quality.
My NASA Data program leaders and instructors collaborating with educators from the North Carolina Space Grant at NASA’S Langley Research Center June 26, 2024. Teachers were at NASA Langley as part of the North Carolina Space Education Ambassadors (NCSEA) program and were given demonstrations of the My NASA Data website. NASA/David C. Bowman
Natalie Macke has been teaching for 20 years and is a science teacher at Pascack Hills High School in Montvale, New Jersey. Teachers like Macke help shape the lessons on the site through internships with the My NASA Data team. Teachers’ suggestions were also incorporated to enhance the visualization tool by adding new features that now allow users to swipe between visual layers of data and make side-by-side comparisons. Users can also now click on a location to display latitude and longitude and variable data streamlining the previous site which required manual input of latitude and longitude.
“The new visualization tool is very much a point-and-click layout like our students are used to in terms of just quickly selecting data they want to see,” said Macke. “Instantaneously, a map of the Earth comes up, or just the outline, and they can get the satellite view. So if they’re looking for a specific city, they can find the city on the map and quickly grab a dataset or multiple datasets and overlay it on the map to make visual comparisons.”
Map of the East Coast of the United States from the My NASA Data visualization tool from August 2023 before adding layers of atmospheric satellite data. The image below shows the same map layered with atmospheric measurements.NASA/mynasadata.larc.nasa.gov The East Coast of the United States shown with monthly daytime surface (skin) temperatures from August 2023 overlayed from Earth-observing satellite data using the My NASA Data Earth System Data Explorer visualization tool. The image above shows the same region without the data layer added.NASA/mynasadata.larc.nasa.gov/
Even more valuable than creating visualizations for one specific lesson, elaborated Macke, is the opportunity My NASA Data provides for students to understand the importance of interpreting, verifying, and using datasets in their daily lives. This skill, she said, is invaluable, because it helps spread data literacy enabling users to look at data with a discriminating eye and learn to discern between assumptions and valid conclusions.
“Students can relate the data map to literally what’s happening outside their window, showing them how NASA Earth system satellite data relates to real life,” said Macke. “Creating a data literate public – meaning they understand the context and framework of the data they are working with and realizing the connection between the data and the real world – hopefully will intrigue them to continue to explore and learn about the Earth and start asking questions. That’s what got me into science when I was a little kid.”
Read MoreJoin the My NASA Data Educator Community
About the AuthorCharles G. HatfieldEarth Science Public Affairs Officer, NASA Langley Research Center Share Details Last Updated Sep 16, 2024 Related Terms Explore More 3 min read NASA Mobilizes Resource for HBCU Scholars, Highlighted at Conference Article 9 hours ago 1 min read NASA Moon to Mars Architecture Art Challenge Article 4 days ago 5 min read NASA Finds Summer 2024 Hottest to Date Article 5 days ago Keep Exploring Discover More Topics From NASAMissions
Humans in Space
Climate Change
Solar System
The My NASA Data homepage categorizes content by areas of study called spheres and also Earth as a system.An Ambitious Mission to Neptune Could Study Both the Planet and Triton
Mission concepts to the outer solar system are relatively common, as planetary scientists are increasingly frustrated by our lack of knowledge of the farthest planets. Neptune, the farthest known planet, was last visited by Voyager 2 in the 1980s. Technologies have advanced a lot since that probe was launched in 1977. But to utilize that better technology, we first need to have a mission arrive in the system – and one such mission is being developed over a series of papers by ConEx Research and University College London.
The Arcanum mission is designed to orbit Neptune and land on Triton, giving insight into both objects of interest in the system. Neptune has some of the highest winds in the solar system and the “Great Dark Spot” storm system. Triton is even more interesting, with potential active volcanism and possibly a subsurface ocean.
Given the different requirements to study both the planet and moon, Arcanum is split into three distinct parts – an orbiter, an “orbital maneuverer,” and a lander. Let’s take a look at each one in turn.
Video describing the Arcanum mission concept.Credit – Conex Research YouTube Channel
Somerville is the orbiter’s name, and its primary function is to provide a scientific platform from which to study Neptune. But it will also serve as a communications relay for the lander system, which it will be joined to for most of its voyage to the outer solar system.
The payload includes several cameras, a few spectrometers, a magnetometer, and some other scientific equipment, but most importantly, it will contain a telescope. The telescope will operate in the visible and infrared spectrum, allowing the orbiter to both look at the Neptunian system and search objects farther afield, such as those in the Kuiper Belt.
The system that enables the orbital maneuvering of the lander is known as Tenzing. It will operate in two stages – first after it separates from Somerville and second after the lander disconnects. During its first phase, its purpose is to position the lander accurately for a touchdown on Triton, using its fuel reserves and providing a power top-up to the lander itself. During its second phase, it acts as an orbiting observer and relay station, interfacing communications from the lander to Somerville, which has a much stronger antenna.
Stackup of the Arcanum mission systems, including descriptions of many subcomponents.Credit – McKevitt et al.
Tenzing also has a series of three “penetrators” that will attempt to break through the outer ice shell on Triton, allowing for scientific study of the world’s interior. It’s unclear whether the system designers plan to penetrate the crust entirely to get to a potential undersea ocean,
The lander itself is called Bingham and consists of its own engines, landing pads, and scientific suite. Instruments on board include multiple cameras, a seismometer, a thermometer, and a mass spectrometer. Overall, the instrumentation on the lander would provide a basic understanding of the surface conditions on Triton, though it wouldn’t necessarily be able to dig into the most interesting parts of the moon on its own.
Trident is another mission under consideration for a trip to Neptune, as Fraser explains.All these systems wouldn’t be possible without Starship’s improved launch capability, which is expected to have at least an order of magnitude more carrying capacity to a transfer orbit than many existing commercial rocket solutions. Bingham and Tenzing alone have a “wet” mass (i.e., with propellant) of 550 kg, putting it in a much heavier category than other outer solar system missions. With an expected launch date of 2030 and an expected arrival at Neptune in 2045, there will be plenty of time for Starship to get put through its paces before the launch window. But as of now, Arcanum is only one of several proposed solar system missions and has no major space agency backing. It remains to be seen what our next mission to Neptune will look like. However, the pressure to send one will increasingly build until, eventually, one day, humanity returns to this exciting system.
Learn More:
McKevitt et al – Concept of operations for the Neptune system mission Arcanum
UT – The Planet Neptune
UT – Life on Neptune
UT – What Is The Surface of Neptune Like?
Lead Image:
Artist’s depiction of the Arcanum mission.
Credit – McKevitt et al.
The post An Ambitious Mission to Neptune Could Study Both the Planet and Triton appeared first on Universe Today.
Aura at 20 Years
14 min read
Aura at 20 YearsIntroduction
In the 1990s and early 2000s, an international team of engineers and scientists designed an integrated observatory for atmospheric composition – a bold endeavor to provide unprecedented detail that was essential to understanding how Earth’s ozone (O3) layer and air quality respond to changes in atmospheric composition caused by human activities and natural phenomena. This work addressed a key NASA Earth science objective. Originally referred to as Earth Observing System (EOS)–CHEM (later renamed Aura,) the mission would become the third EOS Flagship mission, joining EOS-AM 1 (Terra) launched in 1999 and EOS-PM 1 (Aqua), launched in 2002. The Aura spacecraft – see Figure 1 – is similar in design to Terra and identical to Aqua. Aura and its four instruments were launched on July 15, 2004 from Vandenberg Air Force Base (now Space Force Base) in California – see Photo.
Figure 1. An artist’s representation of the Aura satellite in orbit around the Earth. Image credit: NASA Photo. A photo of the nighttime launch of Aura on July 15, 2004. Image credit: NASA
In 2014 The Earth Observer published an article called “Aura Celebrates Ten Years in Orbit,” [Nov–Dec 2014, 26:6, pp. 4–18] which details the history of Aura and the first decade of science resulting from its data. Therefore, the current article will focus on the science and applications enabled by Aura data in the last decade. It also examines Aura’s future and the legacies of the spacecraft’s instruments. Readers interested in more information on Aura and the scientific research and applications enabled by its data can visit the Aura website.
Recent Science Achievements from Aura’s Instrument (in alphabetical order)
High Resolution Dynamics Limb Sounder
The capabilities of the High Resolution Dynamics Limb Sounder (HIRDLS) were compromised at launch and operations ceased in March 2008 due to an image chopper stall. Nevertheless, the HIRDLS team was able to produce a three-year dataset notable for high vertical resolution profiles of greater than 1 km (0.62 mi) for temperature and O3 in the upper troposphere to the mesosphere. Though limited, the HIRDLS dataset demonstrated the incredible potential of the instrument for atmospheric research. So much so, that scientists are now in the study phase for a new instrument, part of the proposed Stratosphere Troposphere Response using Infrared Vertically-Resolved Light Explorer (STRIVE) mission, which would have similar capabilities as HIRDLS with advancements in spectral and spatial imaging. (STRIVE is one of four missions currently undergoing one-year concept studies, as part of NASA’s Earth System Explorer Program, which was established in the 2017 Earth Science Decadal Survey. Two winning proposals will be chosen in 2025 for full development and launch in 2030 or 2032.)
Microwave Limb Sounder
The Microwave Limb Sounder (MLS) was developed to study: 1) the evolution and recovery of the stratospheric O3 layer; 2) the role of the stratosphere, notably stratospheric humidity, in climate feedback processes; and 3) the behavior of air pollutants in the upper troposphere. MLS measures vertical profiles from the upper troposphere at ~10 km altitude (6.2 mi) to the mesosphere at ~90 km (56 mi) of 16 trace gases, temperature, geopotential height, and cloud ice. Its unique measurement suite has made it the “go-to” instrument for most data-driven studies of middle atmosphere composition over the last two decades.
Data collection during the past decade has highlighted the ability of the stratosphere to exhibit surprising and/or envelope-redefining behavior, (Envelope-redefining is a term that is used to refer to an event that greatly exceeded previous observed ranges of this event.) MLS observations have been crucial for the discovery and diagnoses of these extreme events. For example, in 2019, a stratospheric sudden warming over the southern polar cap in September – rare in the Antarctic – curtailed chemical processing, leading to an anomalously weak O3 hole. As another example, prolonged hot and dry conditions in Australia during the subsequent 2019–2020 southern summer promoted the catastrophic “Australian New Year” (ANY) fires. MLS observations showed that fire-driven pyrocumulonimbus convection lofted plumes of polluted air into the stratosphere to a degree never seen during the Aura mission.
Apart from those individual plumes, smoke pervaded the southern lower stratosphere, leading to unprecedented perturbations in southern midlatitude lower stratospheric composition, with chlorine (Cl) shifting from its main reservoir species, hydrochloric acid (HCl), into the O3-destroying form, hypochlorite (ClO). Peak anomalies in chlorine species occurred in mid-2020 – months after the fires. State-of-the-art atmospheric chemistry models in which wildfire smoke has properties similar to those of sulfate (SO4) aerosols were unable to reproduce the observed chemical redistribution. New model simulations assuming that HCl dissolves more readily in smoke than in SO4 particles under typical midlatitude stratospheric conditions better match the MLS observations.
As extraordinary as these events were, their impacts on the stratosphere were spectacularly eclipsed by the impact of the January 2022 eruption of the Hunga Tonga-Hunga Ha’apai (Hunga) volcano in the Pacific Ocean. The Hunga eruption lofted about 150 Tg of water vapor into the stratosphere – with initial injections reaching into the mesosphere. The eruption almost instantaneously increased total stratospheric water vapor by about 10%. MLS was the only sensor able to track the plume in the first weeks following the eruption. The Hunga humidity enhancement resulted in an envelope-redefining, low-temperature anomaly in the stratosphere, in turn inducing changes in stratospheric circulation. Repartitioning of southern midlatitude Cl also occurred, though to a lesser degree than following the ANY fires and in a manner broadly consistent with known chemical mechanisms. The Hunga water vapor enhancement has not substantially declined in the 2.5 years since the eruption, and studies indicate that it will likely endure for several more years.
Impacts of the Hunga humidity on polar O3 loss have also been investigated. The timing and location of the eruption were such that the plume reached high southern latitudes only after the 2022 Antarctic winter vortex had developed. Since the strong winds at the vortex edge present a transport barrier, polar stratospheric cloud (PSC) formation and O3 hole evolution were largely unaffected. When the vortex broke down at the end of the 2022 Antarctic winter, moist air flooded the southern polar region, increasing humidity in the region. Cold, moist conditions led to unusually early and vertically extensive PSC formation and Cl activation, but chemical processing ran to completion by mid-July, as typically occurs in southern winter. The cumulative chemical O3 losses ended up being unremarkable throughout the lower stratosphere. The Hunga plume was also largely excluded from the 2022–2023 Arctic vortex. The 2023–2024 Arctic O3 loss season was characterized by conditions that were dynamically disturbed and not persistently cold, and springtime O3 was near or above average. The extraordinary stratospheric hydration from Hunga has so far had minimal impact on chemical processing and O3 loss in the polar vortices in either hemisphere – see Figure 2.
Figure 2. The evolution of MLS water vapor anomalies (deviations from the baseline 2005–2021 climatology) from January 2019 through December 2023 as a function of equivalent latitude at 700 K potential temperature in the middle stratosphere at ~27 km altitude (17 mi). Black contours mark the approximate edge of the polar vortex. The green triangle marks the time of the main Hunga eruption at latitude 20.54°S on January 15, 2022. Figure credit: Updated and adapted from a 2023 paper in Geophysical Research Letters
With the end of Aura and MLS, the future for stratospheric limb sounding observations is unclear. While stratospheric O3 and aerosol will continue to be measured on a daily, near-global basis by the Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (OMPS-LP) instruments on the Suomi National Polar-orbiting Partnership (Suomi NPP) and Joint Polar Satellite System (JPSS-2, -3, and -4) satellites, there are no confirmed plans for daily, near-global observations of either long-lived trace gases or halogenated species – both of which are needed to diagnose observed changes in O3. The only other sensor making such measurements, the Canadian Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE–FTS), is itself older than MLS and, as a solar occultation instrument, measures only 30 profiles-per-day, taking around a month to cover all latitudes. Similarly, no other sensor is set to provide daily, near-global measurements of stratospheric water vapor until the launch of the Canadian High-altitude Aerosols, Water vapour and Clouds (HAWC) mission in the early 2030s. Some potential new mission concepts are under consideration by both NASA and ESA, but they are subject to competition. Even if both instruments are ultimately selected, gaps in the records of many species measured by MLS are inevitable. The MLS PI is leading an effort to develop new technologies that would allow an instrument that could restart MLS measurements to be built in a far smaller mass/power footprint (e.g., 60 kg, 90 W vs. 500 kg, 500 W for Aura MLS), and technologies exist for yet-smaller MLS-like instruments that could assume the legacy of the highly impactful MLS record at low cost in future decades.
Ozone Monitoring Instrument
The Ozone Monitoring Instrument (OMI) continues the Total Ozone Mapping Spectrometer (TOMS) record for total O3 and other atmospheric parameters related to O3 chemistry and climate. It employs hyperspectral imaging in a push-broom mode to observe solar backscatter radiation in the visible and ultraviolet.
OMI is a Dutch–Finnish contribution to the Aura mission, and its remarkable stability and revolutionary two-dimensional (2D) detector (spatial in one dimension and spectral in the other) has produced a two-decade record of science- and trend-quality datasets of atmospheric column observations. OMI continues the long-term record of total column O3 measurements begun in 1979, and its observations of nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (CH2O), and absorbing aerosols provided exceptional spatial resolution for study of anthropogenic and natural trends and variations of these pollutants around the world. Its radiometric and spectral stability has made it a valuable contributor for solar spectral irradiance measurements to complement dedicated solar instruments on other satellites. The many achievements made possible with OMI are documented in a review article.
OMI’s multidecade data records have revolutionized the ability to monitor air quality changes around the world, even at the sub-urban level. In particular, OMI NO2 data have been transformative. Recently, these data were used to track changes in air pollution associated with efforts to control the spread of SARS-CoV-2. OMI’s long, stable data record allowed for changes in pollution levels in 2020 – at the height of global lockdowns – to be put into historical perspective, especially within the envelope of typical year-to-year variations associated with meteorological variability. Many research studies assessed the impact of the pandemic lockdowns on air pollution, supporting novel uses of OMI data for socioeconomic-related research. For example, OMI NO2 data were shown to serve as an environmental indicator to evaluate the effectiveness of lockdown measures and as a significant predictor for the deceleration of COVID-19 spread. OMI NO2 data were also used as a proxy for the economic impact of the pandemic as NO2 is emitted during fossil fuel combustion, which is another proxy for economic activity since most global economies are driven by fossil fuels – see Animation.
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OMI’s datasets are being continued by successor 2D detector array instruments, such as the previously mentioned Copernicus Sentinel-5P TROPOMI mission, the Republic of Korea’s Geostationary Environment Monitoring Spectrometer (GEMS), and NASA’s Tropospheric Emissions: Monitoring of Pollution (TEMPO). All of these missions have enhanced spatial resolution relative to OMI, but have benefited from the innovative retrieval algorithms pioneered by OMI’s retrieval teams.
Tropospheric Emission Spectrometer
The Tropospheric Emission Spectrometer (TES) provided vertically-resolved distributions of a number of tropospheric constituents, e.g., O3, methane (CH4), and various volatile organic compounds. The instrument was decommissioned in 2018 due to signs of aging associated with a failing Interferometer Control System motor encoder bearing. Nevertheless, TES measurements led to a number of key results regarding changes in atmospheric composition that were published over the past 10 years.
Measurements from TES, OMI, and MLS showed that transport of O3 and its precursors from East Asia offset about 43% of the decline expected in O3 over the western U.S., based on emission reductions observed there over the period 2005–2010. TES megacity measurements revealed that the frequency of high-O3 days is particularly pronounced in South Asian megacities, which typically lack ground-based pollution monitoring networks. TES water vapor and semi-heavy water measurements indicated that water transpired from Amazonian vegetation becomes a significant moisture source for the atmosphere, during the transition from dry to wet season. The increasing water vapor provides the fuel needed to start the next rainy season. Measurements of CH4 from TES and carbon monoxide (CO) from Measurements of Pollution in the Troposphere (MOPITT) on Terra showed that CH4 emissions from fires declined at twice the rate expected from changes in burned area from 2004–2014. This finding helped to balance the CH4 budget for this period, because it offset some of the large increases in fossil fuel and wetland emissions. Through direct measurement of the O3 greenhouse gas effect, TES instantaneous radiative kernels revealed the impact of hydrological controls on the O3 radiative forcing and were used to show substantial radiative bias in Intergovernmental Panel on Climate Change (IPCC) chemistry–climate models. The TES team pioneered the retrieval of a number of species, such as peroxyacetyl nitrate, carbonyl sulfide, and ethylene.
The spirit of TES lives on through the NASA TRopospheric Ozone and its Precursors from Earth System Sounding (TROPESS) project, which generates data products of O3 and other atmospheric constituents by processing data from multiple satellites through a common retrieval algorithm and ground data system. TROPESS builds upon the success of TES and is considered a bridge to allow the development of a continuous record of O3 and other trace gas species as a follow-on to TES.
Future of Aura
In April 2023, Aura’s mission operations team performed the last series of maneuvers to maintain its position in the A-Train constellation of satellites. Since then, Aura has begun drifting. As of July 2024, Aura has descended ~5 km (3 mi) in altitude from ~700 km (435 mi) and its equator crossing time has increased by ~9 min from ~1:44 PM local time. This amount of drift is small, and the Aura MLS and OMI retrieval teams are ensuring the science- and trend-quality of the datasets.
As Aura continues to drift, the amount of sunlight reaching its solar panels will slowly decrease and will no longer be able to generate sufficient power to operate the spacecraft and instruments by mid-2026. At this point, the amount of local time drift will still be relatively small – less than one hour – so the retrieval teams will be able to ensure quality for most data products until this time.
In the remaining years, Aura’s aging but remarkably stable instruments will continue to add to the unprecedented two decades of science- and trend-quality data of numerous key tropospheric and stratospheric constituents. Aura data will be key for monitoring the evolution of the Hunga volcanic plume and understanding its continued impact on the chemistry and dynamics of the stratosphere. Observations from MLS and OMI will also be used to evaluate data from new and upcoming instruments (e.g., ESA’s Atmospheric Limb Tracker for Investigation of Upcoming Stratosphere (Altius); NASA’s TEMPO, Plankton, Aerosol, Cloud, ocean Ecosystem (PACE), and Total and Spectral Solar Irradiance Sensor-2 (TSIS-2) missions, or at least used to help minimize the gaps between data collections.
Aura’s Scientific Legacy
The Aura mission has been nothing short of transformative for atmospheric research and applied sciences. The multidecade, stable datasets have furthered process-based understanding of the chemistry and dynamics of atmospheric trace gases, especially those critical for understanding the causes of trends and variations in Earth’s protective ozone layer.
The two decades that Aura has flown have been marked by profound atmospheric changes and numerous serendipitous events, both natural and man-made. The data from Aura’s instruments have given scientists and applied scientists an unparalleled view – including at the sub-urban scale – of air pollution around the world, clearly showing the influence of rapid industrialization, environmental regulations designed to improve air quality, seasonal agricultural burning, catastrophic wildfires, and even a global pandemic, on the air we breathe. The Aura observational record spans the period that includes the decline of O3-destroying substances, and Aura data illustrate the beginnings of the recovery of the Antarctic O3 hole, a result of unparalleled international cooperation to reduce these substances.
Aura’s datasets have given a generation of scientists the most comprehensive global view to date of critical gases in Earth’s atmosphere and the chemical and dynamic processes that shape their concentrations. Many, but not all, of these datasets are being/will be continued by successor instruments that have benefited from the novel technologies incorporated into the design of Aura’s instruments as well as the innovative retrieval algorithms pioneered by Aura’s retrieval teams.
Acknowledgements
The author wishes to acknowledge the decades of hard work of the many hundreds of people who have contributed to the success of the international Aura mission. There are too many to acknowledge here and I’m sure that many names from the early days are lost to time. I would like to offer special thanks to those scientists who, back in the 1980s, first dreamed of the mission that would become Aura.
Bryan Duncan
NASA’s Goddard Space Flight Center (GSFC)
bryan.n.duncan@nasa.gov
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