Accession Number : ADP009130

Title :   Hydrogen Maser Clocks in Space for Solid-Earth Research and Time-Transfer Applications: Experiment Overview and Evaluation of Russian Miniature Sapphire Loaded Cavity,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GREENBELT MD GODDARD SPACE FLIG HT CENTER

Personal Author(s) : Busca, G. ; Bernier, L. G. ; Silvestrin, P. ; Feltham, S. ; Gayerov, B. A.

Report Date : 02 DEC 1993

Pagination or Media Count : 14

Abstract : The Observatoire Cantonal de Neuchatel (ON) is developing for ESTEC a compact H-maser for space use based upon a miniature sapphire loaded microwave cavity, a technique pioneered at VNIIFTRI. Various contacts between West-European parties, headed by ESA, and the Russian parties, headed by RSA, Led to the proposal for flying two H-masers on Meteor 3M, a Russian meteorology satellite in low polar orbit. The experiment will include two masers, one provided by ON and the other by VNIIFTRI. T/F transfer and precise positioning will be performed by both a microwave link, using PRARE equipment, and an optical link, using LASSO-like equipment. The main objectives of the experiment are precise orbit determination and point positioning for geodetic/geophysical research, ultra-accurate time comparison and dissemination as well as in-orbit demonstration of operation and performance of H-masers. Within the scope of a preliminary space H-maser development phase performed for ESTEC at ON in preparation to the joint experiment, a Russian miniature sapphire loaded microwave cavity, on Loan from VNIIFTRI, was evaluated in a full-size EFOS hydrogen maser built by ON. The experimental evaluation confirmed the theoretical expectation that with a hydrogen storage volume of only 0.6S liter an atomic quality factor of 1.5 x 109 can be obtained for a -105 dBm output power. This represents a theoretical Allan deviation of 1.7 x 10-15 averaged on a 1000 s time interval. From a full-size design to a compact one, therefore, the sacrifice in performance due to the reduction of the storage volume is very small.

Descriptors :   *MASERS, *FREQUENCY STANDARDS, *EXPERIMENTAL DESIGN, ARTIFICIAL SATELLITES, COMPARISON, DEMONSTRATIONS, HYDROGEN, INTERVALS, MICROWAVES, OPERATION, ORBITS, OUTPUT, PHASE, POWER, QUALITY, SAPPHIRE, TIME INTERVALS, USSR, NETHERLANDS, SWITZERLAND, SOLID STATE LASERS, CAVITY RESONATORS, COMPARISON, SPACECRAFT COMPONENTS.

Subject Categories : Test Facilities, Equipment and Methods
      Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE