  In 1999, the highly compact and variable BL Lac object AO 0235+164 was
identified as the highest brightness temperature active galactic nucleus
observed with the VLBI Space Observatory Programme (VSOP), with T_B > 5.8 x
10^{13} K. The sub-milliarcsecond radio structure of this source has been
studied with dual-frequency (1.6 and 5 GHz), polarization-sensitive VSOP
observations during 2001 and 2002. Here we present the results of this
monitoring campaign. At the time of these observations, the source was weakly
polarized and characterized by a radio core that is clearly resolved on
space-ground baselines.
