Geodesy and Geophysics Laboratory (61A) Local News Archive

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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.

Estimate of Global Mean Sea Level Variations updated with NASA GSFC std1504 orbits through 2017.1

Mean Sea Level Curve Computed from TOPEX, Jason-1, Jason-2, Jason-3 altimeter data 1993 to 2017.1, 3.2 mm/yr

As part of the MEASURES project, NASA GSFC/Code 61A (F. Lemoine, N. Zelensky, B. Beckley, R. Ray) routinely provide updates for the "Integrated Multi-Mission Ocean Altimeter Data for Climate Research" product at NASA's Physical Oceanography Distributed Active Archive Center (PODAAC). NASA GSFC's contributions include the Satellite Laser Ranging (SLR) and DORIS Doppler-determined orbits (computed with the std1504 standards) as well as refinements to the altimeter data and validation of the altimetric product. The development of the SSH Climate Data Record (CDR) is a collaborative effort under the auspices of the NASA MEaSURE’s program from NASA/GSFC, JPL, University of South Florida, University of Colorado, and the NOAA Laboratory for Satellite Altimetry.

The URL for the direct link to the altimetry data at PODAAC is:
Frank Lemoine & Richard Ray

NRK TV (Norway) features the need for a precise Terrestrial Reference Frame, & discusses role of NASA & the Space Geodesy Program


Image of VLBI antenna

NRK TV in Norway has published a video feature (in Norwegian) discussing the importance,and challenges of global cooperation in making precise measurements to support the maintenance of an international terrestrial reference frame necessary for natural hazard and global change studies. The video also discusses the future plans for cooperation with NASA in the construction of the geodetic station in Ny Alesund. The video features interviews (in English) with SGP Manager Stephen Merkowitz (Code 61A @ NASA GSFC; time index 5:26, 8:45, 10:20) and colleagues Hayo Hase ( AGGO, La Plata Argentina ; time index 11:14 20:07) Ludwig Combrinck ( HartRAO, South Africa ; time index 6:24, 17:24; Per Erik Opseth, Laila Lovhoiden, Gary Johnston (Geoscience Australia, time index 20:53, 23:05), and others, as well as a visit to NASA GSFC and GGAO . The full URL for the television program is:

Stephen Merkowitz

Weijia Kuang (61A), Terence Sabaka (61A) and Antti Pulkkinen (674) are awarded a Goddard Senior Fellows Innovation Challenges grant


Depiction of Magnetic field lines coming out of the Earth's core

Weijia Kuang (61A), Terence Sabaka (61A) and Antti Pulkkinen (674, Space Weather Laboratory) have been awarded a Goddard Senior Fellows Innovation Challenges grant, entitled “Development of a prototype high-precision dynamic geomagnetic framework." This grant will be used to test the idea of combining geodynamo modeling (MoSST_DAS; Modular Scalable Self-consistent and Three dimensional Data Assimilation Scheme: [Reference, Kuang et al., IUGG, Melbourne, Australia, 2011]) and geomagnetic field modeling (CM) to develop a dynamic-based geomagnetic modeling system (currently called "dynamic field modeling"), and apply this new system to other science research and applications.

Weijia Kuang

Successful Asynchronous Laser Ranging Between GGAO & LRO

Depiction of Greenbelt Laser Station to LRO Spacecraft Geometry

Evan Hoffman (61A), Xiaoli Sun (698, Planetary Geology, Geophysics and Geochemistry Laboratory),Tom Zagwodzki (61A) and Jan McGarry (61A) had great success with the two-way asynchronous laser ranging to the Lunar Orbiter Laser Altimeter (LOLA) in orbit about the Moon, on Sunday and Tuesday nights this week (April 2, 2017 & April 4, 2017). The Lunar Reconnaissance Orbiter (LRO) spacecraft was temporarily pointed at the Earth such that the approximately 100 microradian spot size of the laser (about 35 km on the Earth's surface) would periodically pass over the Greenbelt (Maryland) site over a 30 minute period. Uplink laser pulses at 1064nm were recorded by LOLA, and downlink pulses were recorded at the 1.2 m (48 inch) telescope at the Goddard Geophysical and Astronomical Observatory (GGAO). As a test prior to the LOLA ranging, the Ajisai geodetic satellite (altitude 1485 km, inclination 50 deg), was tracked in the infrared (IR) using the 48" (1.2m) telescope. The 48” (1.2 m) telescope performed extremely well. The main purpose of the ranging to & from Lunar Reconnaissance Orbiter (LRO) was to verify the performance of LOLA laser #2, and re-calibrate the pointing of the instrument, nearly nine years after the launch of the LRO spacecraft into lunar orbit.

Jan Mcgarry & Evan Hoffman

Science Team Meetings for GEDI and ICESAT-2


GEDI Science Team Meeting (Annapolis, MD), April 4-6, 2017. Code 61A attendees were Bryan Blair , Michelle Hofton and Scott Luthcke.


ICESAT-2 Science Team Meeting (Austin, TX), April 10-12, 2017. The Code 61A attendees were Claudia Carabajal, Scott Luthcke and Taylor Thomas.

Scott Luthcke

Bryant Loomis (SGT @ Code 61A) wins RHG award, "Exceptional Achievement for Science"


Image of RHG Award Recipient, B. Loomis

Bryant Loomis (SGT @ Code 61A) has won the RHG award for Exceptional Achievement for Science for his work developing the GSFC mascon products for GRACE , and science preparations for GRACE Follow-On .

Scott Luthcke

"EOP and scale from continuous VLBI observing: CONT campaigns to future VGOS networks"

Dan Macmillan (NVI Inc @ Code 61A) has published a paper in the Journal of Geodesy. This paper discusses the precision of the EOP (Earth Orientation Parameters) and terrestrial scale from VLBI CONT campaigns (~3 week sessions of continuous VLBI observations) and shows that most recent CONTs are close to the GNSS level of precision. Further, simulations shown in the paper demonstrate that the continuous observations available from the VGOS network in 5-10 yrs will yield precision 3X better than current CONTs for networks of 25-30 sites. The paper (Macmillan, 2017) is available from the URL:
Dan Macmillan & John Gipson

GEDI passes CDR!!

The GEDI (Global Ecosystem Dynamics Investigation) Lidar mission passed CDR (Critical Design Review) on February 24, 2017. This is a major mission milestone. It means full steam ahead for Launch Readiness by September 2018, and to be manifested for flight to the International Space Station by early 2019.
Scott Luthcke

A 10-Year Comparison of Water Levels Measured with a Geodetic GPS Receiver versus a Conventional Tide Gauge

Richard Ray (Code 61A) has published a paper as co-author with Kristine M. Larson (University of Colorado, Boulder, USA), & Simon Williams (National Oceanography Center, UK) analyzing ten years of sea level data from the Friday Harbour tide gauge (San Juan islands, Washington State) with water levels derived using GPS reflections from a geodetic GPS receiver. The full paper in the "Journal of Atmospheric and Ocean Technology" is available at the URL:
Richard Ray

New Laboratory Created

The Codes 610 and 690 Division Directors, Piers and Paul, agreed that it made sense to change the organizational structure of Codes 610 and 690 to better align the organizations with their funding lines from HQ SMD. In order to accomplish this, a new Laboratory was created in Code 610 named the Geodesy and Geophysics Laboratory, Code 61A. Some of the members of Codes 694, 698, 690.1 and 690.2 are now a part of this new lab. The current Code 698 has been renamed the Planetary Geology, Geophysics, and Geochemistry Laboratory and retains some of the members of the previous Code 698 along with one member from Code 694. A few members of Codes 694 and 698 will be realigned into the current Codes 612, 614, and 618. Codes 690.2 and 694 have been disbanded.

These changes are not meant to have any impact on your work in Codes 690 and 610, or your collaborations with colleagues across the directorate. The vast majority of people will not move offices either. We count on intra-directorate collaboration to make Goddard stronger and more productive than ever before.

Your Sciences Directorate management is firmly committed to pulling down barriers that might impede productive collaborations. We need to leverage the strength that collaborations across our science endeavors can bring to our research and continue enhancing our fine collaborations with technologists, scientists and engineers both inside and outside the Agency.

Content will be added to the Geodesy and Geophysics Lab's pages as it is made available.
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