  The RadioAstron space radio telescope provides a unique opportunity to study
the extreme brightness temperatures ($\mathrm{T_B }$) in AGNs with
unprecedented long baselines of up to 28 Earth diameters. Since interstellar
scintillation (ISS) may affect the visibilities observed with space VLBI
(sVLBI), a complementary ground based flux density monitoring of the
RadioAstron targets, which is performed near in time to the VLBI observation,
could be beneficial. The combination/comparison with the sVLBI data can help to
unravel the relative influence of source intrinsic and ISS induced effects,
which in the end may alter the conclusions on the $\mathrm{T_B }$ measurements
from sVLBI. Since 2013, a dedicated monitoring program has been ongoing to
observe the ISS of RadioAstron AGN targets with a number of radio telescopes.
Here we briefly introduce the program and present results from the statistical
analysis of the Effelsberg monitoring data. We discuss the possible effects of
ISS on $\mathrm{T_B }$ measurements for the RadioAstron target B0529+483 as a
case study.
