Geodesy and Geophysics Laboratory (61A) Local News Archive

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Geodesy Technology Innovation


The Summer 2022 issue of CuttingEdge (A NASA GSFC periodical dedicated to emerging technologies) features work by Scott Luthcke (61A) and partners on the gravity-measuring Atom Interferometer Gravity Gradiometer (AIGG) in an article entitled "Satellite Geodesy – Innovation Born at Goddard" (pp. 7–9).

The Atom Interferometer Gravity Gradiometer, developed in partnership with the Fremont, California-based AOSense, offers the potential for accurate, direct, real-time measurement of Earth’s gravitational field and its changes over time. Scott Luthcke and Goddard physicist Babak Saif (Code 551) led development of the gravity-measuring technology, which works by pulsing a laser through a cloud of super-cooled atoms. Measuring the laser’s interaction with the atoms creates an interference pattern. Scientists know how the atoms should be-have at a quantum level, so the interference serves as a real-time measurement of gravity’s pull on the atoms.

Shortest Day Gets Attention

Stephen Merkowitz (61A) was recently interviewed by media outlets such as the Associated Press, The World on Public Radio, and Verify for articles about the recent shortest length of day on record. Measurements of the Earth’s length of day are performed daily by the Space Geodesy Project as part of NASA’s participation in the National Earth Orientation Service.

NASA Space Geodesy Project Hosts Summer Interns


The NASA Space Geodesy Project hosted seven interns over the summer: two high school students, four undergraduates, and one graduate student. Six interns were partly or completely virtual, one was onsite; These interns worked with different scientists and engineers of the of the Space Geodesy Project over the summer (June - August 2022) on projects related to Very Long Baseline Interferometry (VLBI) or Lunar Laser Ranging (LLR).

The interns and their projects were:
  • Josh Wu ( Texas Academy of Math & Science ). Project: “Modeling RF Notch Filter to Predict 20K Insertion Loss and Rejection”. NASA Mentors: Lawrence Hilliard (NASA SGP VLBI Technologist) & Jeffrey Dorman (NASA SGP Operations Manager).
  • Joseph Conaty ( Eleanor Roosevelt High School, Greenbelt, Maryland ). Project: “Cryo STEM: Radio Frequency Monitoring System (RFMS) Graphical User Interface (GUI).” NASA Mentors: Lawrence Hilliard (NASA SGP VLBI Technologist) & Jeffrey Dorman (NASA SGP Operations Manager).
  • Simon Matin (University of New Mexico). Project: “Avoiding Spaceborne Radio Frequency Interference for Astronomical Observations”. NASA mentors: Dr. Nlingi Habana (SAIC@ Code 61A) & Lawrence Hilliard (NASA SGP VLBI Technologist).
  • Joshua Batstone ( University of Maryland, College Park ) Project: "Star image Analysis for Lunar Laser Ranging (LLR)" Worked both virtually and onsite with NASA Mentor Evan Hoffman (Code 61A), and Dr. Russet Macmillan ( Apache Point LLR Observatory, New Mexico) to develop improved software to aid in the calibration of star images for use at Apache Point during LLR.
  • Joseph Skeens. ( University of Texas at Austin): Project: “Automated detection of spurious signals in VLBI phase calibration data”. Worked onsite with NASA mentor, VLBI scientist Leonid Petrov (Code 61A) as an SAIC summer intern. Joe is a Ph.D Student at the University of Texas at Austin, and his advisor is Dr. Srinivas Bettadpur.
  • Ludvig Rodung & Tuss Anzelius ( Chalmers University, Sweden), hosted in Greenbelt by NVI inc. Project: “Deriving gaussian models for (radio) sources”. Worked with John Gipson (NVI @ Code 61A, NASA GSFC), IVS Analysis Coordinator and leader of the NVI VLBI group for the NASA Space Geodesy Project.
We hope the in situ and virtual experiences were enjoyable for the interns. All the interns who were in the Greenbelt area were at some time able to interact in person with the NASA scientists, and also visit the Goddard Geophysical and Astronomical Observatory (GGAO) . The GGAO is one of the handful of sites in the world that hosts all four geodetic techniques, and is critical for the maintenance of the International Terrestrial Reference Frame (ITRF).
Frank Lemoine

NASA GLOBE Land Cover Challenge 2022: Land Cover in a Changing Climate

The Global Learning and Observations to Benefit the Environment (GLOBE) Program invites you to take part in our upcoming Land Cover Challenge: “Land Cover in a Changing Climate.”

The photos you take using The GLOBE Program’s GLOBE Observer app document the current land cover and may also show evidence of land cover or land use change in the area. We especially encourage you to look for places you know have changed (or where you know change is coming), and put any information about the reasons or timing for that change in the field notes section. While existing land cover databases (such as the 50-year record from the Landsat satellite) may be able to indicate where change is happening, they don’t always include the reasons why those changes occurred, so any local, on-the-ground knowledge you share with us can be especially helpful.

Loomis Recognized for Excellence

Bryant Loomis (61A) was awarded the AGU 2021 Editor’s Citation for Excellence in Refereeing for outstanding service to the authors and readers of JGR: Solid Earth.

SLAP in Spain for LIAISE Field Campaign

Goddard's Scanning L-band Active Passive (SLAP) airborne soil moisture sensor is participating in the European Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment (LIAISE) campaign, with applications to Planetary Boundary Layer and related science. Ed Kim (617), Hessam Izadkhah (617/Aerotek), Albert Wu (61A/ATA Aerospace), and NASA Langley's B200 aircraft are currently in Spain for the campaign.

Habana Authors Article for The Orbital Index

The Orbital Index’s latest issue featured a guest article, “GRACE, the bumpy road so far,” by Nlingi Habana (61A/SSAI) highlighting some of the role and some of the main findings of the GRACE mission and those of its successor, GRACE-FO.

Space Geodesy Project Hosts Tour

The Space Geodesy Project (SGP) hosted NASA Acting Administrator Steve Jurczyk, Associate Administrator for Science Mission Directorate Thomas Zurbuchen, and the NASA Goddard Executive Council for a tour of the geodetic stations at the Goddard Geophysical and Astronomical Observatory (GGAO). Stephen Merkowitz (61A), Jan McGarry (61A), Evan Hoffman (61A), Mark Clampin (600), Jim Irons (610), and several other members of SGP supported the tour. The clear sky that evening provided excellent viewing of the laser from the MOBLAS-7 Satellite Laser Ranging Station as seen in this tweet by Dr. Zurbuchen.

NCSA Science Story Features SAA Work

National Center for Super Computing Applications (NCSA) featured a science story on geomagnetic South Atlantic Anomaly (SAA) prediction results from 61A's Geomagnetic Group.

Kuang, Sabaka, and Tangborn Highlight the SAA

Weijia Kuang (61A), Terence J. Sabaka (61A) and Andrew Tangborn (UMBC) contributed texts and figures of South Atlantic Anomaly (SAA) to the EOS Science News article entitled “The Herky-Jerky Weirdness of Earth’s Magnetic Field” by J. Duncombe.

CNN Article Mentions GEDI and SED Scientists

Change in the South Atlantic Anomaly (SAA) was the subject of the CNN article 'A growing dent in Earth's magnetic field could impact satellites and spacecraft.' Highlighted in the article was the Global Ecosystem Dynamics Investigation (GEDI) mission, laboratory members Bryan Blair, Terry Sabaka, Weijia Kuang, and Andrew Tangborn, as well as Shri Kanekal from GSFC's Heliospheric Physics Laboratory (672).

Coronavirus Impacts Field Work

Goddard Space Flight Center airborne campaigns are highlighted in a recent Capital Weather Gang article in The Washington Post. The article describes the novel coronavirus's impact on scientific research and field campaigns.

NASA Code61A personnel received Honor Awards in 2019

Bryan Blair (Code 61A) David Rowlands (Code 61A) received NASA Honor awards in 2019. Carey Noll received an SLR Pioneer Certificate from the International Laser Ranging Service (ILRS). David Gordon received the Peter McGregor Prize of the Astronomical Society of Australia, as part of the DiFX Collaboration.

Bryan Blair (Code 61A) received the NASA Honor Award - Exceptional Technology Achievement Medal, with the citation: "For pioneering development of waveform lidar sensor technology for land surface characterization, vegetation structure, biomass, and mapping land and sea ice change. "

David Rowlands (Code 61A) received the NASA Honor Award - Exceptional Service Medal, with the citation, "For nearly four decades of sustained exemplary performance delivering technical innovations and capabilities that have advanced numerous NASA Earth and planetary missions."

Dr. Toshimichi Otsubo, Chair of the International Laser Ranging Service (LRS), presented Carey Noll (Code 61A) with a "Pioneer Certificate" at the 2019 SLR Technical Workshop in Stuttgart, Germany (Oct. 21-24, 2019), "In recognition of her dedication, vision and creativity in supporting all aspects of the ILRS".

David Gordon (NVI @ Code 61A, NASA GSFC) received the Peter McGregor Prize of the Astronomical Society of Australia as part of the DiFX Collaboration (an international team) for contributing to the development of the DiFX software with the following Citation:
"The Distributed FX Correlator (DiFX) is a software package that contains tools necessary to turn an array of radio telescope signals into a functioning radio interferometer. The DiFX has contributed significantly to reducing the barrier to entry and play a major role in radio astronomy research internationally. The system has enabled a wide range of science, as testified by the very high number of references to the key technical papers. The open-access nature of the software has put a new tool in the hands of astronomers, with demonstrated positive results. Its scalability and adaptability has and continues to enable researchers to tailor its behaviour and pursue what would otherwise be difficult science goals."
The members of the DiFX collaboration include: Adam Deller (Leader, Swinburne University of Technology, Australia), Walter Alef (Max Planck Institute for Radio Astronomy, Bonn, Germany), James Anderson (GFZ/Potsdam, Germany), Matthias Bark (NRAO, USA), Matthew Bailes (Swinburne University of Technology, Australia), Walter Brisken (NRAO, USA). Roger Cappallo (MIT Haystack Observatory, USA), Geoff Crew (MIT Haystack Observatory, USA), Richard Dodson (The University of Western Australia), David Gordon (NVI @ Code 61A, NASA GSFC), Zheng Meyer-Zhao (Netherlands Institute for Radio Astronomy, The Netherlands), John Morgan (Curtin University, Australia), Chris Phillips (CSIRO Australia), Cormac Reynolds (CSIRO Australia), Jon Romney (NRAO, USA), Helge Rottman (Max Planck Institute for Radio Astronomy, Bonn, Germany), John Spitzak (US Naval Observatory), Matteo Stagni (National Institute for Astrophysics, Italy), Steven Tingay (Curtin University, Australia), Jan Wagner (Max Planck Institute for Radio Astronomy, Bonn, Germany), Mark Wainright (NRAO, USA) Randall Wayth (Curtin University, Australia).
Scott Luthcke

Proceedings of the 2018 IVS General Meeting in Longyearbyen (Svalbard) are now available online

The "Proceedings of the International VLBI Service for Geodesy and Astrometry 2018 General Meeting, Global Geodesy and the Role of VGOS–Fundamental to Sustainable Development”, has been published and is available online as a NASA Conference Publication: NASA/CP–2019-219039 . The document was edited by Dirk Behrend, Kyla Armstrong and Karen Baver of NVI @ Code 61A, NASA GSFC. The volume includes 59 papers covering the following topics:

1. Building the VGOS Network.
2. VGOS Technique and Observation.
3. Legacy S/X and Mixed Legacy/VGOS Operations.
4. VLBI Core Products and Their Improvements.
5. Extending the Scope of VLBI Usage/Applications.

The full document is available at the following URL . (Size ~130 MB).
Dirk Behrend

Code 61A authors Contribute to Special Issue of the Journal of Geodesy on Satellite Laser Ranging (SLR)

The NASA Space Geodesy Project team members from the Geodesy and Geophysics Laboratory, contributed to the Journal of Geodesy special issue on Satellite Laser Ranging (SLR) , formally published as J. Geodesy, Volume 93, Number 11, November 2019. SGP team members contributed to ten of the twenty papers in the special issue as authors. The special issue highlights the current state of the technique, the science and operational products that are being delivered, and the future technological evolution of the space geodesy technique.

Some of the papers include:

Preface to the second special issue on Laser Ranging, Pavlis, E.C., Luceri, V., Otsubo, T., Schreiber, U. J Geodesy (2019) 93: 2159. .

The ILRS: approaching 20 years and planning for the future, Pearlman, M.R., Noll, C.E., Pavlis, E.C., Lemoine, F.G., Combrink, L., Degnan J.J. , Kirchner, G., Schreiber, U. J Geodesy (2019) 93: 2161.

Laser geodetic satellites: a high-accuracy scientific tool, Pearlman, M., Arnold, D., Davis, M. et al. J Geod (2019) 93: 2181.

Information resources supporting scientific research for the international laser ranging service, Noll, C.E., Ricklefs, R., Horvath, J. et al. J Geodesy (2019) 93: 2211.

NASA’s satellite laser ranging systems for the twenty-first century, McGarry, J.F., Hoffman, E.D., Degnan, J.J. et al. J Geod (2019) 93: 2249.

Modernizing and expanding the NASA Space Geodesy Network to meet future geodetic requirements, Merkowitz, S.M., Bolotin, S., Elosegui, P. et al. J Geodesy (2019) 93: 2263.

Transitioning the NASA SLR network to Event Timing Mode for reduced systematics, improved stability and data precision, Varghese, T., Ricklefs, R.L., Pavlis, E.C., Kuzmicz-Cieslak, M., Merkowitz, S.M. J Geodesy (2019) 93: 2345.

Systematic errors in SLR data and their impact on the ILRS products, Luceri, V., Pirri, M., Rodríguez, J., Appleby, G., Pavlis, E.C., Müller, H. J Geod (2019) 93: 2357.

Time and laser ranging: a window of opportunity for geodesy, navigation, and metrology , Exertier, P., Belli, A., Samain, E., Meng, W., Zhang, H., Tang, K., Schlicht, A., Schreiber, U., Hugentobler, U., Prochàzka, I., Sun, X., Mcgarry, J.F., Mao, D., Neumann, G.A. J Geodesy (2019) 93: 2389.

Rapid response quality control service for the laser ranging tracking network, Otsubo, T., Müller, H., Pavlis, E.C. et al. J Geodesy (2019) 93: 2335.
Stephen Merkowitz

Smithsonian's Air & Space features Space Geodesy

The September issue of the Smithsonian's Air & Space magazine describes how space geodesy is tracking the effects of global change down to the millimeter and highlights the Space Geodesy Project’s (SGP) new station in Texas. Several laboratory members were quoted in the article.

New NASA VGOS Antenna Installed and Passes Site Acceptance Test at McDonald Observatory

NASA and University of Texas Team at McDonald Geodetic Observatory in front of new NASA VGOS Antenna, March 3, 2019 (Photo, courtesy Univ. of Texas)
"Photo of the NASA visitors, and the University of Texas team at the McDonald Geodetic Observatory, Fort Davis, Texas, in front of the new NASA VLBI Geodetic Observing System (VGOS) antenna, on March 3, 2019 (Photo courtesy of the University of Texas)."

The NASA Space Geodesy Project (SGP) has taken the next step in expanding the NASA Space Geodesy Network (NSGN) with the procurement of a VLBI Global Observing System (VGOS) 12-m radio telescope for a new core site located at the McDonald Observatory, near Fort Davis, Texas. Intertronic Solutions Inc. completed the installation of the antenna early in February 2019. An engineering room-temperature feed, developed and installed by MIT/Haystack Observatory, was used to support the pointing tests. On February 15, 2019 several extragalactic sources were observed. The antenna successfully passed the Site Acceptance Test (SAT) on February 20, 2019. A cryogenic, broad-band signal chain will be installed in April 2019. Afterwards the station will begin commissioning activities, and later in the year will being participating in VGOS test sessions, organized in coordination with the International VLBI Service for Geodesy and Astrometry (IVS).

Contact Stephen Merkowitz ( for more information.

Stephen Merkowitz

Poster Blowout 2019 is in the books!

photo of people at the poster party

Photos from this year's Poster Blowout are available now. Congratulations to everyone, especially this year's winners!

Bryan Blair is the 2018 recipient of the Moe I. Schneebaum Memorial Award for Engineering.


Bryan Blair (NASA GSFC, Code 61A)is the 2018 recipient of the Moe I Schneebaum Award in Engineering. The Moe I. Schneebaum Memorial Award for Engineering was created in memory of Moe I. Schneebaum’s far-reaching contributions to space technology and to the Goddard Space Flight Center. This award is the Center’s highest recognition for engineering contributions toward advancing and extending the technology of space flight.

There will be an award ceremony held in September/October 2018.

Scott Luthcke

CDDIS as part of EOSDIS receives the 2015 Pecora Award

William T Pecora Award Certificate for 2015 for the NASA CDDIS

EOSDIS was awarded the 2015 Pecora award. This prestigious William T. Pecora award is given to groups that make outstanding contributions toward understanding the Earth by means of remote sensing. The citation highlights the EOSDIS accomplishments in providing an open archive system for a global user community.

CDDIS is one of twelve DAACs supporting EOSDIS efforts through the Earth Science Data and Information System (ESDIS) project. Carey Noll , CDDIS Manager, accepted their award certificate from Andy Mitchell, ESDIS Project Manager, and Jeanne Behnke, Deputy Project Manager/Operations, at the February 2018 EOSDIS Distributed Active Archive Center (DAAC) Managers Meeting, at Oak Ridge National Laboratory, Tennessee.
Carey Noll

Poster Blowout 2018

Note from the Director:
I would like to thank the Director’s Science Committee for putting on an amazingly successful event where scientists and engineers across Goddard shared their work and made new contacts. The interdisciplinary interactions were especially exciting and crossed all four science disciplines.

Click the title of this news item or the image below for more images from the poster party. scientists standing in front of a poster

The NASA CDDIS has another year of record growth in 2017


The Crustal Dynamics Data Information System (CDDIS) had another year of record growth with 1.7B file downloads (206TB) of data transferred to over 260K unique users in 2017. EOSDIS (Earth Observing System Data and Information System) reports that CDDIS led the twelve Distributed Active Archive (DAACs) in the number of files downloaded last year. Furthermore, CDDIS GNSS (Global Navigation Satellite System) data/products accounted for three of the top data sets distributed by EOSDIS.

- The CDDIS now provides GNSS real-time streams from over 330 global sites as well as nearly 40 real-time product streams to the public through the NTRIP (Networked Transport of RTCM via Internet Protocol) real-time caster. These data streams include 38 NASA GDGPS (Global Differential GPS) sites as well as 31 sites provided by the University of Chile for testing in support of the READI (Real-time Earthquake Analysis for Disaster Mitigation) initiative.

- In December 2016, CDDIS installed an extensive system upgrade using virtual machine architecture for reliability and expandability, providing better infrastructure (power, network connectivity) and increased storage capability. A streamlined archive operations architecture and data upload process were also implemented.

Carey Noll

NASA Takes Next Step for a New VGOS Antenna in Texas

Aerial View of McDonald Geodetic Observatory in Fort Davis Texas, showing locations of the new VLBI and SLR stations
"Aerial view of the proposed locations for the VLBi and SLR instruments at McDonald Observatory, Fort Davis, Texas. The SLR site is located on Mt. Fowlkes, at an elevation of 2027.4 m; the VLBI instrument will be in the valley at an elevation of 1906.1 m. A distance of 827.3 m will separate the two geodetic instruments."

The NASA Space Geodesy Project (SGP) is taking the next step in expanding the NASA Space Geodesy Network (NSGN) with the procurement of a VLBI Global Observing System (VGOS) 12-m radio telescope for a new core site to be located at the McDonald Observatory, near Fort Davis, Texas. NASA recently awarded a contract to InterTronics Solutions, Inc for a 12-m VGOS radio telescope to be installed in the Fall of 2018. The proposed McDonald Geodetic Observatory (MGO) is being developed by NASA and the University of Texas-Austin Center for Space Research and will be hosted by the University of Texas McDonald Observatory. MGO will also include the NASA next-generation Satellite Laser Ranging (SLR) system and permanent GNSS receivers. The MGO VGOS station will be the fourth broadband-capable station in the NASA network, which now includes Kokee Park (Hawaii), the Goddard Geophysical and Astronomical Observatory (GGAO, Greenbelt, Maryland), and the Haystack Observatory (Westford, Massachusetts).

Contact Jim Long ( for more information.

James Long

Correlated Atmosphere Noise in VLBI Analysis

Hana Krásná (TU Wien) made a presentation at the IAG meeting in Kobe, Japan: ''Correlated Atmosphere Noise in VLBI Analysis'', by Hana Krásná and John Gipson (NVI @ NASA GSFC, Code 61A) . She demonstrated that modeling station dependent measurement noise in the VieVs VLBI analysis software improves the repeatability of station positions and the agreement between VLBI and GPS determinations of Polar Motion. John Gipson had demonstrated the same effect in Solve, the Goddard VLBI software, in 2007, but the new study provides the first independent verification.

Contact John Gipson ( for more information.

John Gipson

Richard Ray Contributes to Review Volume on Satellite Altimetry

Richard Ray (NASA GSFC @ Code 61A) and Gary Egbert (Oregon State University, Coravallis, Oregon) have co-authored a chapter entitled "Tides and Satellite Altimetry" in a new book to be published in the Autumn 2017 by CRC Press. The volume includes 18 separate chapters on different applications of satellite alitmetry. The editors for this volume are Professor Detlef Stammer (Universität Hamburg, Germany) and Dr. Anny Cazenave (Laboratoire d’Etudes en Géophysique et Océanographie Spatiale, Centre National d’Etudes Spatiales, Toulouse, France). The new volume is an update to an earlier book volume on satellite altimetry "Satellite Altimetry and Earth Sciences" edited by L.L. Fu and A. Cazeanve, published in 2001 by Academic Press.

Contact Richard Ray ( for more information.

Richard Ray

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