GRGS > The GRGS > About the GRGS

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The Space Geodesy Research Group (GRGS) was officially created on February 17, 1971 at 4:00 pm at the Bureau des Longitudes, at a meeting attended by:

  • the President of the Bureau des Longitudes (BdL ; A. Gougenheim),
  • the President of the Centre National d’Etudes Spatiales (CNES ; J-F. Denisse),
  • the Director of the Institut Géographique National (IGN ; G. Laclavère),
  • the Director of the Observatoire de Paris (OP ; J. Delhaye).

These four original directors also created the GRGS Steering Committee that day, and they laid out its ground rules in a simple, co-signed letter describing the constituent elements of the GRGS and its rules of operation:

  • a Steering Committee
  • a Scientific Council (whose members were designated that day)
  • an Executive Director appointed for a three-year, renewable term (the first was J. Kovalevsky)
  • research staff belonging to member organizations or to other agencies
  • technical and administrative staff made available by member organizations or recruited on a contractual basis (J. Villecrose from the IGN was appointed Administrative Secretary. There is a separate budget for each team, as well as a common budget administered together).

This was the culmination of successive actions that had occurred since the launching of the first artificial Earth satellite on October 4, 1957 and the state of events that had happened many years previously. To understand the French context in February 1971 and the decisions taken, it is necessary to recall the events that have shaped, prepared, and marked the period before the creation of the GRGS.

1 - The French geodetic community, and in particular IGN, put considerable energy into international cooperation and had done so since its inception, specifically with the International Union of Geodesy and Geophysics, or IUGG (the IUGG was established in November 1918 and its statutes were adopted in 1919) and the International Association of Geodesy (IAG). P.Tardi was Secretary General of the AIG from 1945 to 1960, J-J. Levallois held this position from 1960 to 1975 followed by M. Louis, with assistant secretaries for the same periods (J-J Levallois, M. Louis, C. Boucher).

2 - At the international level, France was thus responsible for the International Time Bureau (BIH) housed at the Observatoire de Paris (Director: B. Guinot) and for the International Gravimetric Bureau (BGI) (P. Tardi was its director from 1958 to 1974).

3 - From 1952, the French community (IGN and IPGP) was heavily involved in preparing for the International Geophysical Year 1957-1958, with the creation of the French National Committee of the AIG, under the Chairpersonship of the R-P.Lejay, then President of the French National Committee of Geodesy and Geophysics (CNFGG) with J. Coulomb as Secretary General. J. Coulomb, G. Laclavère, P. Tardi became part of the special committee of the International Geophysical Year established by the International Commission of Scientific Unions in which 77 countries participated. On October 4, 1957, the first artificial satellite was launched by the USSR, which had been planned within the framework of this commission, but which few countries actually believed would happen. This event created a shock wave as we know in all these disciplines and in the political world.

The International Council of Scientific Unions thus created a special committee on space research, COSPAR (Committee of Space Research).The first meeting was held in Nice in 1960 with P. Muller, astronomer at the Observatoire de Paris-Meudon, who had performed the first astrometric observations of artificial satellites, as the French representative. CNES, the French Space Agency, was created on December 19, 1961.

4 - Thanks to A. Danjon, Director of the Observatoire de Paris, celestial mechanics in France had a new start with the Bureau des Longitudes with J. Kovalevsky as Director, (PhD in the U.S. in 1958 with D. Brouwer, author of the first analytical theory of artificial satellite motion in 1959), and Assistant B. Morando (who had done research on the resonances of artificial satellites). The Thursday seminars at the Bureau des Longitudes played an important role as a crucible for creating a space geodetic community bringing together people from various institutes, universities, and CNES. Courses on spatial and celestial mechanics were created along with a diploma (Observatoire de Paris and University of Paris VI) from the beginning of the first space age.

5 - The first international experiments in geodesy were undertaken to establish a global geodetic network using the ECHO 1 and 2 satellites (1961-1963). In France, we had the Muller cameras and the ballistic chambers at IGN. The results were presented at the Geodetic Symposium in Paris in 1964 (liaison between France-North Africa) led by J-J. Levallois (IGN). In addition, the first results were obtained with Doppler receivers and the American system, TRANSIT, and the first results were also obtained with the flashes emitted by the satellite (American satellite ANNA then satellites from the GEOS series. Photographs were also taken at Meudon with the Schmitt telescope).

6 - French geodetic experiments began with the launch of the first geodetic satellite Diapason (February 1966) and Diademe (February 1967) from Hammaguir (Algeria). The French had their first success in laser telemetry with the first echoes obtained at St. Michel (FRANCE) in January 1965 from the American satellite BEB (experiment conducted by the Aeronomy Department of the CNRS under the direction of J-E. Blamont, by Mr. and Mrs. Bivas, and then J. Gaignebet). The first echoes were obtained in the U.S. in October 1964. Success was also obtained later by ONERA with photography of laser echoes and the development of a cooperation between ONERA and the geodetic community in several areas.

7 - Cooperative research was carried out in the program RCP 133, created by CNRS management on February 20, 1967 for geodetic mesurement by artificial satellites from Europe to Africa and South America. The French satellites DIADEMES and the American satellites PAGEOS, and GEOS A and B were used. (Director J-J. Levallois, assistant F. Barlier). Franco-American exchanges and cooperation continued to increase, with several missions and visits to U.S. centres and many exchanges (M. Lefebvre, G. Balmino, G. Brachet). Participation in the founding conference of Space Geophysics in Williamstown, Massachusetts (US) in July 1969 (J-C. Husson, F. Barlier, A. Orsag, O. Calame). Arrival at the Observatoire Paris-Meudon of researchers (K. Lambeck and M. Gaposchkin) who had contributed to the first models of the Earth’s gravitational field, Standard Earth I and II, which had been developed at the Smithsonian Astrophysical Observatory in Cambridge.

8 - European cooperation: the Journées Luxembourgeoises de Géodynamique were a crucible for developing European cooperation in space geodesy: cooperation with ORB, P. Melchior, P. Package and Luxembourg; J. Flick, cooperation with the DGFI of Munich (M. Schneider, C. Reigber); cooperation with the countries of Eastern Europe and the USSR (cooperation Interobs and Intercosmos).

9 - The implementation of the international and global programme ISAGEX under French management with G. Brachet as the Executive Director (1970). France had privileged relationships of cooperation with the U.S.A. as well as the USSR. The following countries were members: East and West Germany, Australia, USA, Finland, France, Greece, Japan, Netherlands, Poland, the United Kingdom, sweden, Switzerland, the USSR. Laser data was used as well as satellited image data obtained by photographing the satellite on a background of stars, or flashes of light emitted by teh satellite (satellite GEOS). The French satellite PEOLE, in orbit at a longitude slightly higher than the euqator, was launched from Kourou (French Guiana) in December, 1970, and has been very useful for space geodesy.

10 - Following the various events mentioned above, and the recommendations of the Williamstown Conference (July 1969), and given the long-term proposals in geodynamics (F. Barlier and F. Lefebvre, late 1969), a department of "Space Geodesy" was created within the Mathematics and Processing Division of the Space Centre in Bretigny, France on March 27, 1970 (J-F. Denisse). On 1 April, 1971, the staff who would make up the Department of Space Geodesy of the GRGS, newly created on February 17, 1971, were assigned for a period of one year. (General Aubinière). This assignment would be renewed each year.

11 - There were many international research projects to be done and several international partnerships to be developed.

In conclusion, as J-J. Levallois wrote in a note to mark the 20th anniversary of the GRGS, the creation of this organization has led to greater efficiency in project implementation, more economical management of funds, the designation of a single organization qualified to make international commitments, to organize the choice of research subjects, and admission to the status of 'laboratory' by CNES, and a link with the CNRS.