• Laser ranging to the moon
    Laser Ranging to the Moon
    NGSLR, located at NASA GSFC's Goddard Geophysical and Astronomical
    Observatory (GGAO),is shown ranging to the Lunar Reconnaissance Orbiter (LRO)
    orbiting the Moon. The LRO Laser Ranging (LR) system enables the spacecraft
    to achieve its precision orbit determination requirement.
  • antenna
    VLBI 2010
    VLBI2010, located at NASA GSFC's Goddard
    Geophysical and Astronomical Observatory
    (GGAO), is the next generation of
    geodetic VLBI systems currently
    under development.
  • Monument brace
    Drilled Brace Monument for GNSS Antenna
    The newly installed drilled brace monument for the
    Global Navigation Satellite System (GNSS) antenna at
    NASA GSFC's Goddard Geophysical and Astronomical
    Observatory (GGAO). The multi-GNSS-capable
    receiver will track signals from several GNSS including
    GPS, GLONASS, and Galileo.
    DORIS Antenna
    The Doppler Orbitography and Radio-positioning Integrated
    by Satellite (DORIS) antenna located at NASA GSFC's Goddard
    Geophysical and Astronomical Observatory (GGAO) tracks
    satellites equipped with DORIS beacons; NGSLR can be seen
    in the background.

  • Sun pointing test

SGP is completing the implementation of a new 12-meter broadband Very Long Baseline Interferometry (VLBI) station at NASA's Kōkeʻe Park Geophysical Observatory (KPGO) on Kauai, Hawaii. This blog follows the progress towards the station completion with updates from the team about once a week.

Latest news

Special collection of DORIS-related titled, "The Scientific Applications of DORIS in Space Geodesy", published in the journal "Advances in Space Research"
IDS logo The International DORIS Service (IDS) has just published in the journal "Advances in Space Research" a special collection of papers entitled "The Scientific Applications of DORIS in Space Geodesy". DORIS is one of the four fundamental techniques that contributes to the terrestrial reference frame. It is also a prime tracking technique for LEO satellites, including those that map the oceans with radar altimetry.

The eighteen papers in the special issue cover five themes:

  • ITRF2014 -- the papers discuss the DORIS contribution to the new realization of the International Terrestrial Reference Frame (ITRF);
  • DORIS Ultra-Stable Oscillator (USO), Jason-2;
  • Precise Orbit Determination;
  • DORIS System and Network;
  • Intertechnique comparisons of DORIS products.

The papers are published in Volume 58, Number 12 of the Journal Adv. Space Res. Of the 18 papers, four were led or featured significant contributions from NASA GSFC & JPL authors. The Guest Editors of the special issue were Frank G. Lemoine (Code 61A, Geodesy & Geophysics Laboratory, NASA GSFC) and Ernst J.O. Schrama (Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands).

This special issue marks the third time the DORIS community has published a special issue in a peer-reviewed journal dedicated to scientific and technical aspects of the DORIS technique. The previous special issues dedicated to DORIS were published in the journal Adv. Space Res. (two volumes in 2010) and in the Journal of Geodesy (2006).

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CDDIS unavailable November 30-December 01 for transition to new systems
CDDIS logoOn November 30, 2016 at 13:00 UTC, CDDIS will terminate all services (ftp, CDDIS/ILRS/SGP websites, data deliveries) as we transition to all new hardware and facilities. We are projecting about 24 hours to fully move to our new facilities and ensure all operations are back to normal. As such, all users need to plan on a 24+ hour disruption of service to the CDDIS archive with resumption of normal operations no earlier than December 01, 2016 at 17:00 UTC.

In summary the following will take place:

  • 30 November 2016 at 13:00 UTC – All current production services (ftp, http, etc) will be shutdown.
  • 01 December 2016 at 17:00 UTC – all web and anonymous ftp access is restored for access to the archive. NOTE: restoration could occur sooner but no guarantees are made.
  • Currently used addresses, e.g., cddis.nasa.gov or cddis.gsfc.nasa.gov, will continue to work as before the transition. However, if you are using a numeric IP address to access any CDDIS resources your scripts will fail as all current IP addresses will change during the transition.
  • 02 December 2016 – All CDDIS operations should be returned to normal service.

While CDDIS is unavailable, users can access one of the other data centers supporting the services:

All questions on the CDDIS transition should be directed to cddis-help@lists.nasa.gov.

Space Geodesy Project Issues Solicitation for New VLBI Antennas
SGP logoThe Space Geodesy Project posted a request for proposal for the construction, deployment and commissioning of up to three Very Long Baseline Interferometer (VLBI) antennas that will be part of the new NASA Space Geodesy Network (NSGN) and the VLBI2010 Global Observing System (VGOS). Details on the solicitation can be found here:

User Profile: Dr. Erricos C. Pavlis
Dr. Erricos PavlisNASA Earthdata has published a user profile of Dr. Erricos Pavlis as part of their "Who uses NASA Earth science data?" series.

First Circular for the 20th International Workshop on Laser Ranging Released
LW20 logoGFZ Potsdam and the International Laser Ranging Service (ILRS) are pleased to announce that the 20th International Workshop on Laser Ranging will be held in Potsdam Germany during the week of October 09-14, 2016 at GFZ Potsdam, Telegrafenberg. The first circular has been released.

LARES + LAGEOS 1&2 Lense-Thirring results selected as EPJ-C cover
March 2016 cover of the European Physical JournalThe article, "A test of general relativity using the LARES and LAGEOS satellites and a GRACE Earth gravity model," (Ciufolini et. al.) has been published in the March 2016 issue of the European Physical Journal-C. Furthermore, a figure from this paper has been selected for the cover of that issue.

The passing of Dr. Bob Coates
Crustal Dynamics Project logo.We are saddened to report the passing of Dr. Bob Coates, a long time colleague in the field of space geodesy. Bob was the Project Manager for NASA’s very successful Crustal Dynamics Project (CDP). Bob helped advance the SLR and VLBI technologies at NASA GSFC, incorporating them as the key measurement components of the CDP, which succeeded in describing the relative motions of the Earth’s plates with unprecedented accuracies. He will be remembered for his many contributions in both science and engineering, and for his guidance and encouragement to those who worked in the program.

Positive leap second to be introduced
image of upper part of a clock showing numbers 11, 12 and 1.A positive leap second will be introduced at the end of December 2016. More information is available from the IERS.

Now 40, NASA's LAGEOS Set the Bar for Studies of Earth
LAGEOS satelliteOn May 4, 1976, NASA launched a cannonball-shaped satellite that transformed studies of Earth’s shape, rotation and gravity field.

LAGEOS – short for Laser Geodynamic Satellite – was the first NASA orbiter dedicated to the precision measurement technique called laser ranging. With it, scientists have measured the movement of Earth’s tectonic plates, detected irregularities in the rotation of the planet, weighed it, and tracked small shifts in its center of mass.

Small deviations in the satellite’s orbit were used to develop early models of Earth’s gravitational field. Further perturbations in the orbit helped explain how sunlight heating small objects can affect their orbits, including near-Earth asteroids.

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NASA Station Leads Way for Improved Measurements of Earth Orientation, Shape
12-meter (39-foot) antenna at the Kōke‘e Park Geophysical Observatory in HawaiiNASA has demonstrated the success of advanced technology for making precise measurements of Earth’s orientation and rotation – information that helps provide a foundation for navigation of all space missions and for geophysical studies of our planet.

The technology includes a new class of radio antenna and electronics that provide broadband capabilities for Very Long Baseline Interferometry, or VLBI. This technique is used to make precise measurements of Earth in space and time.

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Using Quasars to Measure the Earth: A Brief History of VLBI

Looking Down a Well: A Brief History of Geodesy

Staff profiles