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Summary of the 10th DSCOVR EPIC and NISTAR Science Team Meeting


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Summary of the 10th DSCOVR EPIC and NISTAR Science Team Meeting

Introduction

The 10th Deep Space Climate Observatory (DSCOVR) Earth Polychromatic Camera (EPIC) and National Institute of Standards and Technology (NIST) Advanced Radiometer [NISTAR] Science Team Meeting (STM) was held October 16–18, 2024. Over 50 scientists attended, most of whom were from NASA’s Goddard Space Flight Center (GSFC), with several participating from other NASA centers, U.S. universities, and U.S. Department of Energy laboratories. There was one international participant – from Estonia. A full overview of DSCOVR’s Earth-observing instruments was published in a previous article in The Earth Observer and will not be repeated here. This article provides the highlights of the 2024 meeting. The meeting agenda and full presentations can be downloaded from GSFC’s Aura Validation Data Center.

Opening Presentations

The opening session of the 10th DSCOVR STM was special. Former U.S., Vice President Al Gore attended the opening session and gave a presentation at the panel discussion “Remote Sensing and the Future of Earth Observations” – see Photo. Gore was involved in the early days of planning the DSCOVR mission, which at that time was known as Triana. He reminisced about his involvement and praised the team for the work they’ve done over the past decade to launch and maintain the DSCOVR mission. Following the STM Opening Session, Gore spoke at a GSFC Engage session in Building 3 later that afternoon on the same topic, but before a wider audience. [Link forthcoming.]

Following Gore’s remarks, the remainder of the opening session consisted of a series of presentations from DSCOVR mission leaders and representatives from GSFC and National Oceanic and Atmospheric Administration (NOAA). Thomas Neumann [GSFC, Earth Sciences Division (ESD)—Deputy Director] opened the meeting and welcomed Vice President Gore and the STM participants on behalf of the ESD. Adam Szabo [GSFC—DSCOVR Project Scientist] briefly reported that the spacecraft was still in “good health.” The EPIC and NISTAR instruments on DSCOVR continue to return their full science observations. He also gave an update on DSCOVR Space Weather research. Alexander Marshak [GSFC—DSCOVR Deputy Project Scientist] briefly described DSCOVR mission history and the science results based on DSCOVR observations from the first Sun–Earth Lagrange point (hereinafter, the L1 point). He also summarized the major EPIC and NISTAR results to date. At this time, more than 125 papers related to DSCOVR are listed on the EPIC website. Elsayed Talaat [NOAA, Office of Space Weather observations—Director] discussed the future of Earth and space science studies from the L1 point.

DSCOVR photo
Photo. Former U.S. Vice President Al Gore spoke at the opening session of the 10th DSCOVR Science Team Meeting. This photo shows Gore together with Makenzie Lystrup [NASA’s Goddard Space Flight Center (GSFC)—Center Director], Christa Peters-Lidard [GSFC, Director of the Science and Exploration Directorate], Elsayed Talaat [National Oceanic and Atmospheric Administration (NOAA)—Director of the Office of Space Weather Observations], Dalia Kirschbaum [GSFC—Director of Earth Sciences], other GSFC management, and members of the DSCOVR Science Team.
Photo credit: Katy Comber (GSFC)

Updates on DSCOVR Operations

The DSCOVR mission components continue to function nominally. The meeting was an opportunity to update participants on progress over the past year on several fronts, including data acquisition, processing, and archiving, and release of new versions of several data products. The number of people using DSCOVR data continues to increase, with a new Science Outreach Team having been put in place to aid users in several aspects of data discovery, access, and user friendliness.

Amanda Raab [NOAA, DSCOVR Mission Operations and Systems] reported on the current status of the DSCOVR mission. She also discussed spacecraft risks and issues such as memory fragmentation and data storage task anomalies but indicated that both these issues have been resolved.

Hazem Mahmoud [NASA’s Langley Research Center (LaRC)] discussed the work of the Atmospheric Science Data Center (ASDC), which is based at LaRC. He showed DSCOVR mission metrics since 2015, focusing on data downloads and the global outreach of the mission. He noted that there has been a significant rise in the number of downloads and an increasing diversity of countries accessing ozone (O3), aerosol, and cloud data products. Mahmoud also announced that the ASDC is transitioning to the Amazon Web Services cloud, which will further enhance global access and streamline DSCOVR data processing.

Karin Blank [GSFC] covered the discovery of a new type of mirage that can only be seen in deep space from EPIC. The discussion included the use of a ray tracer in determining the origin of the phenomenon, and under what conditions it can be seen.

Alexander Cede [SciGlob] and Ragi Rajagopalan [LiftBlick OG] gave an overview of the stability of the EPIC Level-1A (L1A) data over the first decade of operation. They explained that the only observable changes in the EPIC calibration are to the dark count and flat field can – and that these changes can be entirely attributed to the temperature change of the system in orbit compared to prelaunch conditions. No additional hot or warm pixels have emerged since launch and no significant sensitivity drifts have been observed. The results that Cede and Rajagopalan showed that EPIC continues to be a remarkably stable instrument, which is attributed to a large extent to its orbit around the L1 point, which is located outside the Earth’s radiation belts and thus an extremely stable temperature environment. Consequently, in terms of stability, the L1 point is far superior to other Earth observation points, e.g., ground-based, low-Earth orbit (LEO), polar orbit, or geostationary Earth orbit (GEO).

Marshall Sutton [GSFC] discussed the state of the DSCOVR Science Operation Center (DSOC). He also talked about processing EPIC Level-1 (L1) data into L2 science products, daily images available on the EPIC website, and special imaging opportunities, e.g., volcanic eruptions.

EPIC Calibration

After 10 years of operation in space, the EPIC instrument on DSCOVR continues to be a remarkably stable instrument. The three presentations describe different ways that are used to verify the EPIC measurements remain reliable.

Conor Haney [LaRC] reported on anomalous outliers during February and March 2023 from the broadband shortwave (SW) flux using EPIC L1B channel radiances. To ensure that these outliers were not a result of fluctuations in the EPIC L1B channel radiances, both the EPIC radiance measurements and coincident, ray-matched radiance measurements from the Visible Infrared Imaging Radiometer Suite (VIIRS), on the Suomi National Polar-orbiting Partnership (Suomi NPP) platform, were processed using the same deep convective cloud invariant target (DCC-IT) algorithm. This analysis confirmed that the anomalous behavior was due to the DCC-IT algorithm – and not because of fluctuations in the EPIC L1B channel radiances. The improved DCC-IT methodology was also applied to the EPIC L1B radiances. The results indicate that the EPIC record is quite stable with a lower uncertainty than when processed using the previous DCC-IT methodology.

Igor Geogdzhaev [NASA’s Goddard Institute for Space Studies (GISS)/Columbia University] reported that EPIC Visible–Near Infrared (VIS-NIR) calibration based on VIIRS (on Suomi NPP) data has showed excellent stability, while VIIRS (on NOAA-20 and -21) derived gains agree to within 1–2%. Preliminary analysis showed continuity in the gains derived from Advanced Baseline Imager (ABI) data. (ABI flies on NOAA’s two operational Geostationary Operational Environmental Satellite–Series R satellites – GOES-17 and GOES-18.

Liang–Kang Huang [Science Systems and Applications, Inc. (SSAI)] reported on updates to the EPIC ultraviolet (UV) channel sensitivity time dependences using Sun-normalized radiance comparisons between EPIC and measurements from the Ozone Mapping and Profiler Suite (OMPS) Nadir Mapper (NM) on Suomi NPP, with coinciding footprints and solar/satellite angles. Huang’s team determined vignetting factors in the sensitivity calibration between 2021–2024, as a function of charge coupled device (CCD) pixel radius and pixel polar angles, using special lunar measurement sequences.

NISTAR Status and Science with Its Observations

The NISTAR instrument remains fully functional and continues its uninterrupted data record. The NISTAR-related presentations during this meeting included more details on specific topics related to NISTAR as well as on efforts to combine information from both EPIC and NISTAR.

Steven Lorentz [L-1 Standards and Technology, Inc.] reported that the NISTAR on DSCOVR has been measuring the irradiance from the sunlit Earth in three bands for more than nine years. The three bands measure the outgoing total and reflected-solar radiation from Earth at a limited range of solar angles. To compare the long-term stability of EPIC and NISTAR responses, researchers developed a narrowband to wideband conversion model to allow the direct comparison of the EPIC multiband imagery and NISTAR SW – see Figure 1 – and silicon photodiode channels. Lorentz presented daily results spanning several years. The comparison employed different detectors from the same spacecraft – but with the same vantage point – thereby avoiding any model dependent orbital artifacts.

DSCOVR Figure 1
Figure 1. NISTAR daily average shortwave (SW) radiance plotted for each year from 2017–2024. The results indicated a 10% increase in the shortwave radiance as the backscattering angle approaches 178° in December 2020. A 6% increase is noted in September of the same year.
Figure credit: Steven Lorentz (L-1 Standards and Technology)

Clark Weaver [University of Maryland, College Park (UMD)] used spectral information from the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY), which flew on the European Space Agency’s (ESA) Envisat satellite from 2002–2012, to fill EPIC spectral gaps. He reported on construction of a composite height resolution spectrum that was spectrally integrated to produce SW energy. Weaver explained that he compared the EPIC reflected SW with four-hour averages from Band 4 on NISTAR. He used spectral information from SCIAMACHY to fill in gaps. Weaver also discussed results of a comparison of area integrated EPIC SW energy with observations from NISTAR . 

Andrew Lacis [GISS] reported on results of analysis of seven years of EPIC-derived planetary albedo for Earth, which reveal global-scale longitudinal variability occurring over a wide range of frequencies – with strong correlation between nearby longitudes and strong anticorrelation between diametrically opposed longitudes. This behavior in the Earth’s global-scale energy budget variability is fully corroborated by seven years of NISTAR silicon photodiode measurements, which view the Earth with 1º longitudinal resolution. This analysis establishes the DSCOVR mission EPIC/NISTAR measurements as a new and unmatched observational data source for evaluating global climate model performance– e.g., see Figure 2.

DSCOVR Figure 2
Figure 2. This graph shows the diurnal variation in planetary albedo as measured by EPIC for five different eight-day-Blurred Meridians relative to Global Mean for 2021 [left] and 2022 [right].
Figure credit: Andrew Lacis [GISS]

Wenying Su [LaRC] discussed global daytime mean SW fluxes within the EPIC field of view produced from January 2016–June 2024. These quasi-hourly SW fluxes agree very well with the Synoptic data product from the Clouds and the Earth’s Radiant Energy System (CERES) instruments (currently flying on the Terra and Aqua, Suomi NPP, and NOAA-20 platforms) with the root mean square errors (rmse) less than 3 W/m2. This SW flux processing framework will be used to calculate NISTAR SW flux when Version 4 (V4) of the NISTAR radiance becomes available. Su noted that SW fluxes from EPIC are not suitable to study interannual variability as the magnitude of EPIC flux is sensitive to the percentage of daytime area visible to EPIC.

Update on EPIC Products and Science Results

EPIC has a suite of data products available. The following subsections summarize content during the DSCOVR STM related to these products. The updates focus on several data products and the related algorithm improvements. 

Total Column Ozone

Jerry Ziemke [Morgan State University (MSU), Goddard Earth Sciences Technology and Research–II (GESTAR II)] and Natalya Kramarova [GSFC] reported that tropospheric O3 from DSCOVR EPIC shows anomalous reductions of ~10% throughout the Northern Hemisphere (NH) starting in Spring 2020 that continues to the present. The EPIC data, along with other satellite-based (e.g., Ozone Monitoring Instrument (OMI) on NASA’s Aura platform) and ground-based (e.g., Pandora) data, indicate that the observed NH reductions in O3 are due to combined effects from meteorology and reduced pollution, including reduced shipping pollution in early 2020 (during COVID) – see Figure 3. EPIC 1–2 hourly data are also used to evaluate hourly total O3 and derived tropospheric O3 from NASA’s Tropospheric Emissions: Monitoring of Pollution (TEMPO) geostationary instrument. Ziemke explained that comparison of TEMPO data with EPIC data has helped the researchers characterize a persistent latitude-dependent offset in TEMPO total O3 data of ~10–15% from south to north over the North American continent.

DSCOVR Figure 3
Figure 3. This dataset combines input from EPIC, OMPS, and OMI from 2004–2022. The onset of the COVID-19 pandemic in 2020 can be seen clearly in the data as it corresponds to a sudden drop in tropospheric column ozone by ~3 Dobson Units in the Northern Hemisphere.
Figure credit: Jerry Ziemke (Morgan State University, GESTAR-II)

Algorithm Improvement for Ozone and Sulfur Dioxide Products

Kai Yang [UMD] presented a comprehensive evaluation of total and tropospheric O3 retrievals, highlighting the long-term stability and high accuracy of EPIC measurements. He also validated EPIC’s volcanic sulfur dioxide (SO2) retrievals by comparing them with ground-based Brewer spectrophotometer measurements and summarized EPIC’s observations of SO2 from recent volcanic eruptions.

Simon Carn [University of Michigan] showed the first comparisons between the EPIC L2 volcanic SO2 product and SO2 retrievals from the Geostationary Environment Monitoring Spectrometer (GEMS) on the Korean GEO-Kompsat-2B satellite. GEMS observes East Asia as part of the new geostationary UV air quality (GEO-AQ) satellite constellation (which also includes TEMPO that observes North America and will include the Ultraviolet–Visible–Near Infrared (UVN) instrument on the European Copernicus Sentinel-4 mission, that will be launched in 2025 to observe Europe and surrounding areas) – but is not optimized for measurements of high SO2 columns during volcanic eruptions. EPIC SO2 data for the 2024 eruption of Ruang volcano in Indonesia are being used to validate a new GEMS volcanic SO2 product. Initial comparisons show good agreement between EPIC and GEMS before volcanic cloud dispersal and confirm the greater sensitivity of the hyperspectral GEMS instrument to low SO2 column amounts.

Aerosols

Alexei Lyapustin [GSFC] reported that the latest EPIC aerosols algorithm (V3) simultaneously retrieves aerosol optical depth, aerosol spectral absorption, and aerosol layer height (ALH) – achieving high accuracy. He showed that global validation of the single scattering albedo in the blue and red shows 66% and 81–95% agreement respectively, with Aerosol Robotic Network (AERONET) observations – which is within the expected error of 0.03 for smoke and dust aerosols. Lyapustin also reported on a comparison of EPIC aerosol data collected from 2015–2023 by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), which flew on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission. The results show that ALH is retrieved with rmse ~1.1 km (0.7 mi). ALH is unbiased over the ocean and is underestimated by 450 m (1470 ft) for the smoke and by 750 m (2460 ft) for the dust aerosols over land. 

Myungje Choi and Sujung Go [both from University of Maryland, Baltimore County’s (UMBC), GESTAR II] presented results from a global smoke and dust characterization using Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm. This study characterized smoke and dust aerosol properties derived from MAIAC EPIC processing, examining spectral absorption, ALH, and chemical composition (e.g., black and brown carbon). Regions with smoldering wildfires, e.g., North America and Siberia, exhibited high ALH and a significant fraction of brown carbon, while Central Africa showed lower ALH with higher black carbon emissions.

Omar Torres [GSFC] discussed how L1 DSCOVR-EPIC observations are being used to study air quality (i.e., tropospheric O3 and aerosols) globally. Torres noted that this application of EPIC-L1 observations is of particular interest in the Southern Hemisphere (SH) where, unlike over the NH, there are currently no space GEO-based air quality measurements – and no plans for them in the foreseeable future.

Hiren Jethva [MSU, GESTAR II] presented the new results of the aerosol optical centroid height retrieved from the EPIC Oxygen-B band observations. He described the algorithm details, showed retrieval maps, and reviewed the comparative analysis against CALIOP backscatter-weighted measurements. The analysis showed a good level of agreement with more than 70% of matchup data within 1–1.5 km (0.6–0.9 mi) difference.

Jun Wang [University of Iowa] presented his team’s work on advancing the second generation of the aerosol optical centroid height (AOCH) algorithm for EPIC. Key advancements included: constraining surface reflectance in aerosol retrieval using an EPIC-based climatology of surface reflectance ratios between 442–680 nm; incorporating a dynamic aerosol model to characterize aged smoke particles; and employing a spectral slope technique to distinguish thick smoke plumes from clouds. Results show that both atmospheric optical depth (AOD) and AOCH retrievals are improved in the second generation of AOCH algorithm.

Olga Kalashnikova [NASA/Jet Propulsion Laboratory (JPL)] reported on improving brown carbon evolution processes in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) model with EPIC products. She indicated that DSCOVR product evaluation, using lidar aerosol height measurements from CALIOP, led to an improved operational brown carbon product. To better resolve the temporal evolution of brown carbon, chemical transport models need to include more information about near-source fires.

Mike Garay [NASA/Jet Propulsion Laboratory (JPL)] discussed constraining near-source brown carbon emissions from 2024 Canadian ‘zombie’ fires with EPIC products. He reported that fires in British Columbia, Canada showed differences in brown carbon emission near the sources.  Garay explained that their investigation has revealed that these differences were related to fire intensity and variations in vegetation/soil content.

Yuekui Yang [GSFC] presented work that examined the impact of Earth’s curvature consideration on EPIC cloud height retrievals. Biases under the Plane Parallel (PPL) assumption is studied by comparing results using the improved pseudo-spherical shell approximation. PPL retrievals in general bias high and for a cloud with height of 5 km (3 mi), the bias is about 6%.

Alfonso Delgado Bonal [UMBC] stated that the EPIC vantage point offers a unique opportunity to observe not only the current state of the Earth but also its temporal evolution. By capturing multiple observations of the planet throughout the day, EPIC enables statistical reconstruction of diurnal patterns in clouds and other atmospheric parameters. Bonal’s team focused their research on O3 (primarily tropospheric) over the U.S. to demonstrate the presence of a diurnal cycle in the western regions of the continental U.S. However, ground-based data from PANDORA for specific locations do not support these diurnal variations – underscoring the critical role of space-based O3 retrievals. The proposed methodology is not limited to clouds or O3 but is broadly applicable to other EPIC measurements for the dynamic nature of our planet.

Elizabeth Berry [Atmospheric and Environmental Research (AER)] presented results from a coincident DSCOVR–CloudSat dataset [covering 2015–2020]. Cloud properties (e.g., cloud height and optical depth) from DSCOVR and CloudSat are moderately correlated and show quite good agreement given differences in the instruments sensitivities and footprints. Berry explained that a machine-learning model trained on the coincident data demonstrates high accuracy at predicting the presence of vertical cloud layers. However, precision and recall metrics highlight the challenge of predicting the precise location of cloud boundaries.

Anthony Davis [JPL] presented a pathway toward accurate estimation of the cloud optical thickness (COT) of opaque clouds and cloud systems, e.g., supercells, mesoscale convective complexes, and tropical cyclones (TCs). He described the approach, which uses differential oxygen absorption spectroscopy (DOAS) that has resolving power greater than 104 – which is comparable to that of the high-resolution spectrometers on NASA’s Orbiting Carbon Observatory–2 (OCO-2) – but is based upon the cloud information content of EPIC’s O2 A- and B-band radiances. Unlike the current operational retrieval of COT – which uses data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua – the DOAS-based technique does not saturate at COT exceeding ~60. According to a popular TC model with two-moment microphysics, COT in a tropical storm or hurricane can reach well into the hundreds, sometimes exceeding 1000. Davis said that once the new COT estimates become available, they will provide new observational constraints on process and forecast models for TCs.

Ocean

Robert Frouin [Scripps Institution of Oceanography, University of California] discussed ocean surface radiation products derived from EPIC data. He explained that significant advancements have been achieved in processing and evaluating ocean biology and biogeochemistry products derived from EPIC imagery. V1 updates enhanced accuracy by integrating Modern-Era Retrospective analysis for Research and Applications V2 (MERRA-2) ancillary data and refining calculations for atmospheric and surface parameters. Frouin introduced several diurnal products, including hourly photosynthetically active radiation (PAR) fluxes, spectral water reflectance, and chlorophyll-a concentrations. He said that these new MODIS-derived products have been validated through comparisons with data from the Advanced Himawari Imager on the Japanese Himawar–8 and –9 satellites. In order to address the gaps in these diurnal products, Frouin explained that the team developed a convolutional neural network that has been used effectively to reconstruct missing PAR values with high accuracy.

Vegetation

Yuri Knyazikhin [Boston University] reported on the status of the Vegetation Earth System Data Record (VESDR) that provides a variety of parameters including: Leaf Area Index (LAI), diurnal courses of Normalized Difference Vegetation Index (NDVI), Sunlit LAI (SLAI), Fraction of incident Photosynthetically Active Radiation (FPAR) absorbed by the vegetation, Directional Area Scattering Function (DASF), Earth Reflector Type Index (ERTI), and Canopy Scattering Coefficient (CSC). Knyazikhin discussed analysis of the diurnal and seasonal variations of these quantities. EPIC LAI and FPAR are consistent with MODIS-derived measurements of the same parameters.

Jan Pisek [University of Tartu/Tartu Observatory, Estonia] discussed efforts to derive leaf inclination information from EPIC data. The very first evaluation over Tumbarumba site (in New South Wales, Australia) showed that the angular variation in parameters obtained from EPIC reflects the expected variations due to the erectophile vegetation present at the site.

Sun Glint

Tamás Várnai [UMBC, JCET] discussed EPIC observations of Sun glint from ice clouds. The cloud glints come mostly from horizontally oriented ice crystals and have strong impact in EPIC cloud retrievals. Várnai reported that the EPIC glint product is available from the ASDC – see Figure 4. Glint data can help reduce the uncertainties related to horizontally oriented ice crystals and yield additional new insights about the microphysical and radiative properties of ice clouds.

DSCOVR Figure 4
Figure 4. [top row] EPIC glint mask examples over land in [left to right] Paraguay, Sudan, Thailand, and Brazil. [bottom row] The corresponding EPIC glint mask for each image on the top row indicates the band (red, green and blue) and the size of sun glint for each of them.
Figure credit: Tamás Várnai (University of Maryland, Baltimore County)

Alexander Kostinski [Michigan Technology University] explained that because they detected climatic signals (i.e., longer-term changes and semi-permanent features, e.g., ocean glitter), they developed a technique to suppress geographic “noise” in EPIC images that involves introducing temporally (monthly) and conditionally (classifying by surface/cover type, e.g., land, ocean, clouds) averaged reflectance images – see Figure 5. The resulting images display seasonal dependence in a striking manner. Additionally, cloud-free, ocean-only images highlight prominent regions of ocean glitter.

DSCOVR Figure 5
Figure 5. Monthly reflectances for clear land pixels. Earth masquerading as Jupiter; latitudinal bright bands are caused by features such as the Sahara and Antarctica. Black spots are due to the lack or dearth of clear land pixels at that latitude. Repeated spots within latitudinal bands reflect roughly bi-hourly image sampling.
Figure credit: Alexander Kostinski (Michigan Technology University); from a 2024 paper published in Frontiers of Remote Sensing

Jiani Yang [Caltech] reported that spatially resolving light curves from DSCOVR is crucial for evaluating time-varying surface features and the presence of an atmosphere. Both of these features are essential for sustaining life on Earth – and thus can be used to assess the potential habitability of exoplanets. Using epsilon machine reconstruction, the statistical complexity from the time series data of these light curves can be calculated. The results show that statistical complexity serves as a reliable metric for quantifying the intricacy of planetary features. Higher levels of planetary complexity qualitatively correspond to increased statistical complexity and Shannon entropy, illustrating the effectiveness of this approach in identifying planets with the most dynamic characteristics.

Other EPIC Science Results

Guoyong Wen [MSU, GESTAR II] analyzed the variability of global spectral reflectance from EPIC and the integrated broadband reflectance on different timescales. He reported that on a diurnal timescale, the global reflectance variations in UV and blue bands are statistically similar – and drastically different from those observed in longer wavelength bands (i.e., green to NIR). The researchers also did an analysis of monthly average results and found that temporal averaging of the global reflectance reduces the variability across the wavelength and that the variability of broadband reflectance is similar to that for the red band on both timescales. These results are mainly due to the rotation of the Earth on diurnal timescale and the change of the Earth’s tilt angle. 

Nick Gorkavyi [Science Systems and Applications, Inc. (SSAI)] reported that EPIC – located at the L1 point, 1.5 million km (0.9 million mi) away from Earth – can capture images of the far side of the Moon in multiple wavelengths. These images, taken under full solar illumination, can be used to calibrate photographs obtained by lunar artificial satellites. Additionally, he discussed the impact of lunar libration – the changing view of the Moon from Earth, or it’s apparent “wobble” – on Earth observations from the Moon. 

Jay Herman [UMBC] discussed a comparison of EPIC O3 with TEMPO satellite and Pandora ground-based measurement. The results show that total column O3 does not have a significant photochemical diurnal variation. Instead, the daily observed diurnal variation is caused by weather changes in atmospheric pressure. This measurement result agrees with model calculations.

Conclusion

Alexander MarshakJay Herman, and Adam Szabo led a closing discussion with ST participants on how to make the EPIC and NISTAR instruments more visible in the community. It was noted that the EPIC website now allows visitors to observe daily fluctuations of aerosol index, cloud fraction, cloud height, and the ocean surface – as observed from the L1 point. More daily products, (e.g., aerosol height and sunlit leaf area index) will be added soon, which should attract more users to the website.

Overall, the 2023 DSCOVR EPIC and NISTAR STM was successful. It provided an opportunity for participants to learn the status of DSCOVR’s Earth-observing instruments, EPIC and NISTAR, the status of recently released L2 data products, and the science results being achieved from the L1 point. As more people use DSCOVR data worldwide, the ST hopes to hear from users and team members at its next meeting. The latest updates from the mission can be found on the EPIC website

Alexander Marshak
NASA’s Goddard Space Flight Center
alexander.marshak@nasa.gov

Adam Szabo
NASA’s Goddard Space Flight Center
adam.szabo@nasa.gov

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Feb 14, 2025

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      Parker Solar Probe was developed as part of NASA’s Living With a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living With a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. The Applied Physics Laboratory designed, built, and operates the spacecraft and manages the mission for NASA.
      By Geoff Brown
      Johns Hopkins University Applied Physics Laboratory
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      Last Updated Mar 25, 2025 Editor Sarah Frazier Contact Abbey Interrante abbey.a.interrante@nasa.gov Location Goddard Space Flight Center Related Terms
      Heliophysics Goddard Space Flight Center Heliophysics Division Parker Solar Probe (PSP) The Sun Explore More
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    • By NASA
      NASA astronaut Butch Wilmore, left, Roscosmos cosmonaut Aleksandr Gorbunov, second from left, and NASA astronauts Nick Hague, second from right, and Suni Williams, right, are seen inside a SpaceX Dragon spacecraft shortly after splashing down off the coast of Florida, Tuesday, March 18, 2025. NASA’s SpaceX Crew-9 mission returned from a long-duration science expedition aboard the International Space Station. Photo Credit: (Credit: NASA).NASA/Keegan Barber After completing a long-duration stay aboard the International Space Station, NASA’s SpaceX Crew-9 astronauts will discuss their science mission during a postflight news conference at 2:30 p.m. EDT Monday, March 31, from the agency’s Johnson Space Center in Houston. Following the news conference, the crew will be available for a limited number of individual interviews at 3:30 p.m.
      NASA astronauts Nick Hague, Suni Williams, and Butch Wilmore will answer questions about their time in space. The three NASA crew members and Roscosmos cosmonaut Aleksandr Gorbunov returned to Earth on March 18. Gorbunov will not participate in the news conference because of his travel schedule.
      Watch live coverage on NASA+. Learn how to watch NASA content through a variety of additional platforms, including social media.
      Media are invited to attend in person or virtually. U.S. media requesting in-person attendance or media seeking an interview with the crew must contact the NASA Johnson newsroom no later than 5 p.m. on Friday, March 28, at 281-483-5111 or jsccommu@mail.nasa.gov. A copy of NASA’s media accreditation policy is available on the agency’s website. Media participating by phone must dial into the news conference no later than 10 minutes before the start of the event to ask questions. Questions also may be submitted on social media using #AskNASA.
      Hague and Gorbunov lifted off at 1:17 p.m. Sept. 28, 2024, on a SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida. The next day, they docked to the forward-facing port of the station’s Harmony module. Williams and Wilmore launched aboard Boeing’s Starliner spacecraft and United Launch Alliance Atlas V rocket on June 5, 2024, from Space Launch Complex 41 as part of the agency’s Boeing Crew Flight Test. The duo arrived at the space station on June 6. In August, NASA announced the uncrewed return of Starliner to Earth and integrated Wilmore and Williams as part of the space station’s Expedition 71/72 for a return on Crew-9.
      Williams and Wilmore traveled 121,347,491 miles during their mission, spent 286 days in space, and completed 4,576 orbits around Earth. Hague and Gorbunov traveled 72,553,920 miles during their mission, spent 171 days in space, and completed 2,736 orbits around Earth.
      Hague, Williams, and Wilmore completed over 900 hours of research, conducting more than 150 unique experiments. During their time in orbit, the crew studied plant growth and development, tested stem cell technology to improve patient outcomes on Earth, and participated in research to understand how the space environment affects material degradation. They also performed a spacewalk and collected samples from the station’s exterior, studying the survivability of microorganisms in space. Additionally, the crew supported 30 ham radio events with students worldwide and conducted a student-led genetic experiment, helping to inspire the next generation of explorers.
      NASA’s Commercial Crew Program has delivered on its goal of safe, reliable, and cost-effective transportation to and from the International Space Station from the United States through a partnership with American private industry. This partnership is changing the arc of human spaceflight history by opening access to low Earth orbit and the International Space Station to more people, more science, and more commercial opportunities. The space station remains the springboard to NASA’s next great leap in space exploration, including future missions to the Moon and, eventually, to Mars.
      Find more information on NASA’s Commercial Crew Program at:
      https://www.nasa.gov/commercialcrew
      -end-
      Joshua Finch / Jimi Russell
      Headquarters, Washington
      202-358-1100
      joshua.a.finch@nasa.gov / james.j.russell@nasa.gov
      Courtney Beasley
      Johnson Space Center, Houston
      281-483-5111
      courtney.m.beasley@nasa.gov
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      Last Updated Mar 24, 2025 LocationNASA Headquarters Related Terms
      Humans in Space International Space Station (ISS) Missions View the full article
    • By NASA
      NASA Science Live: Aurora Glow, Electric Flow & the EZIE Mission
    • By NASA
      After delivering ten NASA science and technology payloads to the near side of the Moon through NASA’s CLPS (Commercial Lunar Payload Services) initiative and Artemis campaign, Firefly Aerospace’s Blue Ghost Mission 1 lander captured this image of a sunset from the lunar surface. Credit: Firefly Aerospace After landing on the Moon with NASA science and technology demonstrations March 2, Firefly Aerospace’s Blue Ghost Mission 1 concluded its mission March 16. Analysis of data returned to Earth from the NASA instruments continues, benefitting future lunar missions.
      As part of NASA’s CLPS (Commercial Lunar Payload Services) initiative and Artemis campaign, Firefly’s Blue Ghost lunar lander delivered 10 NASA science and technology instruments to the Mare Crisium basin on the near side of the Moon. During the mission, Blue Ghost captured several images and videos, including imaging a total solar eclipse and a sunset from the surface of the Moon. The mission lasted for about 14 days, or the equivalent of one lunar day, and multiple hours into the lunar night before coming to an end.
      “Firefly’s Blue Ghost Mission 1 marks the longest surface duration commercial mission on the Moon to date, collecting extraordinary science data that will benefit humanity for decades to come,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington. “With NASA’s CLPS initiative, American companies are now at the forefront of an emerging lunar economy that lights the way for the agency’s exploration goals on the Moon and beyond.”
      All 10 NASA payloads successfully activated, collected data, and performed operations on the Moon. Throughout the mission, Blue Ghost transmitted 119 gigabytes of data back to Earth, including 51 gigabytes of science and technology data. In addition, all payloads were afforded additional opportunities to conduct science and gather more data for analysis, including during the eclipse and lunar sunset.
      “Operating on the Moon is complex; carrying 10 payloads, more than has ever flown on a CLPS delivery before, makes the mission that much more impressive,” said Joel Kearns, deputy associate administrator for exploration, Science Mission Directorate, NASA Headquarters. “Teams are eagerly analyzing their data, and we are extremely excited for the expected scientific findings that will be gained from this mission.”
      Among other achievements, many of the NASA instruments performed first-of-their-kind science and technology demonstrations, including:
      The Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity  is now the deepest robotic planetary subsurface thermal probe, drilling  up to 3 feet and providing a first-of-its kind demonstration of robotic thermal measurements at varying depths. The Lunar GNSS Receiver Experiment acquired and tracked Global Navigation Satellite Systems (GNSS) signals, from satellite networks such as GPS and Galileo, for the first time enroute to and on the Moon’s surface. The LuGRE payload’s record-breaking success indicates that GNSS signals could complement other navigation methods and be used to support future Artemis missions. It also acts as a stepping stone to future navigation systems on Mars.  The Radiation Tolerant Computer successfully operated in transit through Earth’s Van Allen belts, as well as on the lunar surface into the lunar night, verifying solutions to mitigate radiation effects on computers that could make future missions safer for equipment and more cost effective. The Electrodynamic Dust Shield successfully lifted and removed lunar soil, or regolith, from surfaces using electrodynamic forces, demonstrating a promising solution for dust mitigation on future lunar and interplanetary surface operations. The Lunar Magnetotelluric Sounder successfully deployed five sensors to study the Moon’s interior by measuring electric and magnetic fields. The instrument allows scientists to characterize the interior of the Moon to depths up to 700 miles, or more than half the distance to the Moon’s center. The Lunar Environment heliospheric X-ray Imager captured a series of X-ray images to study the interaction of the solar wind and Earth’s magnetic field, providing insights into how space weather and other cosmic forces surrounding Earth affect the planet.  The Next Generation Lunar Retroreflector successfully reflected and returned laser light from two Lunar Laser Ranging Observatories, returning measurements allowing scientists to precisely measure the Moon’s shape and distance from Earth, expanding our understanding of the Moon’s inner structure.  The Stereo Cameras for Lunar Plume-Surface Studies instrument captured about 9,000 images during the spacecraft’s lunar descent and touchdown on the Moon, providing insights into the effects engine plumes have on the surface. The payload also operated during the lunar sunset and into the lunar night. The Lunar PlanetVac was deployed on the lander’s surface access arm and successfully collected, transferred, and sorted lunar soil using pressurized nitrogen gas, demonstrating a low-cost, low-mass solution for future robotic sample collection. The Regolith Adherence Characterization instrument examined how lunar regolith sticks to a range of materials exposed to the Moon’s environment, which can help test, improve, and protect spacecraft, spacesuits, and habitats from abrasive lunar dust or regolith. The data captured will benefit humanity in many ways, providing insights into how space weather and other cosmic forces may impact Earth. Establishing an improved awareness of the lunar environment ahead of future crewed missions will help plan for long-duration surface operations under Artemis.
      To date, five vendors have been awarded 11 lunar deliveries under CLPS and are sending more than 50 instruments to various locations on the Moon, including the lunar South Pole and far side.
      Learn more about NASA’s CLPS initiative at:
      https://www.nasa.gov/clps
      -end-
      Alise Fisher 
      Headquarters, Washington
      202-617-4977
      alise.m.fisher@nasa.gov
      Natalia Riusech / Nilufar Ramji
      Johnson Space Center, Houston
      281-483-5111
      nataila.s.riusech@nasa.gov / nilufar.ramji@nasa.gov
      Antonia Jaramillo
      Kennedy Space Center, Florida
      321-501-8425
      antonia.jaramillobotero@nasa.gov
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      Last Updated Mar 18, 2025 LocationNASA Headquarters Related Terms
      Commercial Lunar Payload Services (CLPS) Artemis Blue Ghost (lander) Johnson Space Center Kennedy Space Center NASA Headquarters View the full article
    • By NASA
      3 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Media are invited to meet leaders in the space community during the 62nd annual Goddard Space Science Symposium, taking place from Wednesday, March 19, to Friday, March 21, at Martin’s Crosswinds in Greenbelt, Maryland. The symposium will also be streamed online.
      Hosted by the American Astronautical Society (AAS) in conjunction with NASA’s Goddard Space Flight Center in Greenbelt, the symposium examines the current state and future of space science and space exploration at large by convening leading minds across NASA, other government agencies, policy, academia, and industry – collectively navigating a path forward by identifying the opportunities and challenges ahead.
      This year’s theme, “Pathways and Partnerships for U.S. Leadership in Earth and Space Science,” highlights the evolving collaborative landscape between the public and private sectors, as well as how it is helping the United States remain and grow as a leading space power. 
      “Earth and space science are complex by nature, with a growing list of public and private enterprises carving out their space,” said Christa Peters-Lidard, co-chair of the symposium planning committee and Goddard’s director of sciences and exploration. “It’s an exciting time as we work to determine the future trajectory of space exploration in this new era, and the Goddard Space Science Symposium is an instrumental tool for gathering the insights of leading experts across a broad spectrum.”
      AAS President Ron Birk and Goddard Deputy Center Director Cynthia Simmons will deliver the symposium’s opening remarks on March 19, followed by panels on enabling science and exploration from the Moon to Mars and navigating space science and exploration policy. Greg Autry, associate provost for space commercialization and strategy at the University of Central Florida, will deliver the keynote address. The first day will conclude with an industry night reception.
      The second day of the symposium on Thursday, March 20, will feature panels on enhancing U.S. economic leadership through science, the Habitable Worlds Observatory, and the confluence of public science and the private sector. Gillian Bussey, deputy chief science officer for the U.S. Space Force, will serve as the luncheon speaker.
      Panels on the third and final day, March 21, will discuss integrating multi-sector data to advance Earth and space science, the Heliophysics Decadal Survey, and the space weather enterprise. Mark Clampin, acting deputy associate administrator for the NASA Science Mission Directorate, will provide the luncheon address.
      Media interested in arranging interviews with NASA speakers should contact Jacob Richmond, Goddard acting news chief.
      For more information on the Goddard Space Science Symposium and the updated program, or to register as a media representative, visit https://astronautical.org/events/goddard.
      For more information on NASA’s Goddard Space Flight Center, visit https://www.nasa.gov/goddard.
      Media Contact:
      Jacob Richmond
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
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      Last Updated Mar 18, 2025 EditorJamie AdkinsLocationNASA Goddard Space Flight Center Related Terms
      Goddard Space Flight Center View the full article
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