Forthcoming Close Angular Approaches of Planets to Radio Sources and
  Possibilities to Use Them as GR Tests
  During close angular approaches of solar system planets to astrometric radio
sources, the apparent positions of these sources shift due to relativistic
effects and, thus, these events may be used for testing the theory of general
relativity; this fact was successfully demonstrated in the experiments on the
measurements of radio source position shifts during the approaches of Jupiter
carried out in 1988 and 2002. An analysis, performed within the frames of the
present work, showed that when a source is observed near a planet's disk edge,
i.e., practically in the case of occultation, the current experimental accuracy
makes it possible to measure the relativistic effects for all planets. However,
radio occultations are fairly rare events. At the same time, only Jupiter and
Saturn provide noticeable relativistic effects approaching the radio sources at
angular distances of about a few planet radii. Our analysis resulted in the
creation of a catalog of forthcoming occultations and approaches of planets to
astrometric radio sources for the time period of 2008-2050, which can be used
for planning experiments on testing gravity theories and other purposes. For
all events included in the catalog, the main relativistic effects are
calculated both for ground-based and space (Earth-Moon) interferometer
baselines.
