Title: A possible flyby anomaly for Juno at Jupiter,
Abstract: In the last decades there have been an increasing interest in improving the
accuracy of spacecraft navigation and trajectory data. In the course of this
plan some anomalies have been found that cannot, in principle, be explained in
the context of the most accurate orbital models including all known effects
from classical dynamics and general relativity. Of particular interest for its
puzzling nature, and the lack of any accepted explanation for the moment, is
the flyby anomaly discovered in some spacecraft flybys of the Earth over the
course of twenty years. This anomaly manifest itself as the impossibility of
matching the pre and post-encounter Doppler tracking and ranging data within a
single orbit but, on the contrary, a difference of a few mm$/$s in the
asymptotic velocities is required to perform the fitting.
Nevertheless, no dedicated missions have been carried out to elucidate the
origin of this phenomenon with the objective either of revising our
understanding of gravity or to improve the accuracy of spacecraft Doppler
tracking by revealing a conventional origin.
With the occasion of the Juno mission arrival at Jupiter and the close flybys
of this planet, that are currently been performed, we have developed an orbital
model suited to the time window close to the perijove. This model shows that an
anomalous acceleration of a few mm$/$s$^2$ is also present in this case. The
chance for overlooked conventional or possible unconventional explanations is
discussed.