Geodesy and Geophysics Laboratory (61A) Local News Archive

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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

LVIS Team Deployed to Greenland as part of Operatiion IceBridge

' LVIS Team in Thule, Greenland
LVIS Team in Thule, Greenland.

High resolution (50mpixel) LVIS image
An example image from LVIS’ downlooking camera (50 Megapixel Canon 5DSR) showing unique and complex patterns present in the refreezing sea ice adjacent to the calving front of Nioghalvfjerdsbrae Glacier near 79 deg. N, (upper left) in northeastern Greenland, taken on August 29,2017 from 28,000 feet.

The LVIS team is currently deployed in Greenland for an “end of melt season” laser altimeter-mapping mission for the Operation IceBridge. Project . The LVIS sensor was installed on a commercial aircraft (Dynamic Aviation’s B-200T N44U) in early August and deployed on August 22nd to Thule, Greenland. The team completed three science flights out of Thule and has now transitioned to Kangerlussuaq for the next three weeks to complete as many as 13 additional flights. This is the second deployment for the new LVIS Facility sensor following the ABOVE campaign in Canada and Alaska. Michelle Hofton (61A/UMD) is the Mission Scientist leading the field operations. Bryan Blair (61A) led LVIS operations in Thule and David Rabine (61A) is leading LVIS operations in Kangerlussuaq.

Contact Bryan Blair ( for more information.

Bryan Blair

NASA GSFC (Code 61A & Code 595) help OSIRIS-REx Navigation Team In Advance of Earth Flyby

OSIRIS REX Mission Logo

The OSIRIS-REx navigation team has members from the NASA GSFC Navigation and Mission Design Branch (Code 595) and the NASA GSFC Geodesy and Geophysics Laboratory (Code 61A) as well as from other organizations. The Navigation team has been preparing for the OSIRIS-REx (OREX) Gravity Assist (EGA) which will take place on on September 22, 2017 at 12:52 EDT (16:52 UTC) at an altitude of about 16,000 km. This is a close flyby of the Earth and will require detailed Earth modeling for accurate trajectory computation. The purpose of the Earth flyby is to alter the heliocentric trajectory of the spacecraft to continue on its way to rendezvous with the asteroid 101955 Bennu in 2018. The Code 61A version of the NASA precise orbit determination and geodetic parameter estimation software (GEODYN) will be used to compute OREX trajectories during the EGA. In preparation for the EGA, GEODYN has been given extra optical image (camera) capabilities that allow point images of the Earth and the Earth's moon to be used as tracking data. In addition to the camera images, the EGA OREX trajectory solutions will use Earth-based Delta-DOR (Differential-one-way Ranging), Doppler and range tracking data from NASA's Deep Space Network (DSN). GEODYN's high fidelity Earth force models will play an important role. The NASA GSFC personnel participating in Navigation for OSIRIS REx for the Earth flyby include Kenny Getzandanner, Dolan Highsmith, Andrew Liounis (Code 595), and David Rowlands, Joseph Nicholas, Despina Pavlis, Terence Sabaka, and David Rubincam (Code 61A).

Contact David Rowlands for more information.

David Rowlands

Code 61A Personnel attend 25th anniversary celebration of TOPEX launch

Poster Celebrating 25th Anniversary of TOPEX launch
"TOPEX/Poseidon: The most sucessful ocean experiment of all time" -- Professor Walter H. Munk (Scripps Intitute of Oceanography)

Richard Ray (Code 61A) and Brian Beckley (SGT@ Code 61A) attended a celebration in Pasadena, California, commemorating the 25th anniversary of the launch of TOPEX/Poseidon, "the most successful ocean experiment of all time", according to Dr. Walter Munk (UC San Diego/Scripps Institute of Oceanography). The celbration included a series of speeches at presentations at the Van Karman Auditorium (JPL) and in Dabney Hall (Caltech). The presentations included talks by former mission managers, engineers, and scientists from NASA and the CNES. Richard Ray delivered an address on TOPEX and tide models that discussed the seven stages of Tides and TOPEX starting with "Tides are a Nuisance", "Fake Rossby waves are really Tidal signals", to "Everybody is doing it" ... to "Using Internal Tides as an Ocean Thermometer"

Contact Richard Ray ( for more information.

Richard Ray

NASA personnel attend UN GGIM (Global Geospatial Information Management) Meeting

The Seventh Session of the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM) was held on August 2-4, 2017 at the United Nations Headquarters in New York, preceded by a number of related side events on July 31 through August 1, 2017. The meetings brought together senior officials and executives from national geospatial information and statistical authorities within Member States, and international geospatial experts from across the globe. An important outcome of this session was the establishment of a Subcommittee on Geodesy to provide stability and longer-term planning for the Global Geodetic Reference Frame (GGRF). Participating from NASA’s Space Geodesy Program were: Benjamin Phillips (NASA/HQ), Stephen Merkowitz (NASA/GSFC), and Allison Craddock (NASA/JPL) as US Delegates, and Michael Pearlman (Smithsonian Astrophysical Observatory) as a representative of the International Association of Geodesy.

Contact Stephen Merkowitz ( for more information.

Stephen Merkowitz

Printed Version of VLBI Special Issue (Journal of Geodesy) now available

The printed version of the Journal of Geodesy Special Issue on VLBI: Journal of Geodesy, Volume 91, Issue 7, July 2017, is now available at . This volume includes a Preface and 14 scientific articles devoted to various aspects of the VLBI theory, methodology and data analysis.

The special issue includes three papers involving NASA GSFC (Code 61A Authors)

(1) "International VLBI Service for Geodesy and Astrometry, A. Nothnagel, T. Artz, D. Behrend, Z. Malkin, J. Geodesy, 91(7), 711-721, doi: 10.1007/s00190-016-0950-5. URL Link:

(2) "Impact of the VLBI on reference frame and earth orientation studies", David Gordon, 91(7), 735-742, 2017. URL Link:

(3) "EOP and scale from continuous VLBI observing: CONT campaigns to future VGOS networks", Dan MacMillan, J. Geodesy, 91(7), 819-829, 2017. URL Link:

Contact Dirk Behrend ( for more information.

GSFC VLBI Group members contribute to the 9th IVS Technical Operators Workshop (TOW) at MIT Haystack Observatory

Four GSFC VLBI group members contributed to the 9th IVS Technical Operations Workshop (TOW) that was held at the MIT Haystack Observatory in Westford, Massachusetts from April 30 to May 4, 2017. Dirk Behrend organized the 9th IVS Technical Operations Workshop (TOW) together with staff from MIT Haystack Observatory. He was responsible for the overall program and class assignments. He chaired two sessions and moderated the teachers' meeting. Ed Himwich taught classes about four subjects: automated pointing models, Field System station software coding, the impact of operations on data analysis, and near term Field System plans. David Horsley trained VLBI operators in the TIG monitoring suite and Linux System administration. Karine Le Bail gave a science overview lecture that presented various results and applications derived from VLBI data.

Contact Dirk Behrend ( for more information.

Successful Very Long Baseline Interferometry Global Observing System (VGOS) trial on May 22, 2017

The Space Geodesy Project successfully ran a 24-hour trial session of the next generation Very Long Baseline Interferometry Global Observing System (VGOS) on 05/22/2017. Participating stations were: Westford in Massachusetts, Goddard Geophysical and Astronomical Observatory (GGAO) in Maryland, Kōkeʻe Park Geophysical Observatory (KPGO) in Hawaii, Wettzell in Germany, and Yebes in Spain. This session is a first of its kind with the KPGO-Wettzell baseline being the first trans-Pacific/Arctic/Atlantic VGOS fringes ever.

Contact Stephen Merkowitz ( for more information.

Richard Ray co-author on paper analyzing historical tide data from St. Helena

The astronomer Manuel Johnson, a future President of the Royal Astronomical Society, recorded the ocean tides with his own instrument at St. Helena in 1826–1827. With authors David Cartwright (FRS), and Phillip L. Woodworth (National Oceanography Centre, Liverpool, UK), Richard Ray (NASA GSFC, Code 61A) recovered and reanalyzed the St. Helena data, and compared it to modern tidal predictions. The historical data have been digitized and are available online for other researchers. The paper was published in the journal "History of Geo and Space Sceinces". The full text is available at the URL:

Contact Richard Ray ( for more information.

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