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Title: Astrometry of Cassini with the VLBA to improve the Saturn ephemeris

Planetary ephemerides have been developed and improved over centuries. They are a fundamental tool for understanding solar system dynamics, and essential for planetary and small body mass determinations, occultation predictions, high-precision tests of general relativity, pulsar timing, and interplanetary spacecraft navigation. This paper presents recent results from a continuing program of high-precision astrometric very long baseline interferometry (VLBI) observations of the Cassini spacecraft orbiting Saturn, using the Very Long Baseline Array (VLBA). We have previously shown that VLBA measurements can be combined with spacecraft orbit determinations from Doppler and range tracking and VLBI links to the inertial extragalactic reference frame to provide the most accurate barycentric positions currently available for Saturn. Here we report an additional five years of VLBA observations along with improved phase reference source positions, resulting in an improvement in residuals with respect to the Jet Propulsion Laboratory's dynamical ephemeris.
Authors:
; ; ;  [1] ; ;  [2] ;  [3]
  1. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
  2. National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
  3. National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
Publication Date:
OSTI Identifier:
22342154
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 149; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; DOPPLER EFFECT; ECLIPSE; FORECASTING; GENERAL RELATIVITY THEORY; INTERFEROMETRY; MASS; ORBITS; PULSARS; SATELLITES; SATURN PLANET; SOLAR SYSTEM