  The recurrent nova and symbiotic binary RS Oph erupted again in August 2021
for its eighth known outburst. As part of a multi-epoch and frequency campaign,
we observed RS Oph 34 days after the outburst at 5 GHz with the European VLBI
Network (EVN). The radio image is elongated over the east-west direction for a
total extension of about 90 mas (or about 240 AU at the Gaia DR3 distance
d=2.68 [-0.15/+0.17] kpc), and shows a bright and compact central component
coincident with the Gaia astrometric position, and two lobes east and west of
it, expanding perpendicular to the orbital plane. By comparing with the
evolution of emission-line profiles on optical spectra, we found the leading
edge of the lobes to be expanding at 7550 km/s, and i=54 deg as the orbital
inclination of the binary. The 2021 radio structure is remarkably similar to
that observed following the 2006 eruption. The obscuring role of the density
enhancement on the orbital plane (DEOP) is discussed in connection to the
time-dependent visibility of the receding lobe in the background to the DEOP,
and the origin of the triple-peaked profiles is traced to the ring structure
formed by the nova ejecta impacting the DEOP.
