  With the launch of Gaia satellite, detection of many different types of
transient sources will be possible, one of them being optical afterglows of
gamma-ray bursts (GRBs). Using the knowledge of the satellites dynamics and
properties of GRB optical afterglows we performed a simulation in order to
estimate an average GRB detection rate with Gaia. Here we present the
simulation results for two types of GRB optical afterglows, differing in the
observer's line-of-sight compared to a GRB jet axis: regular (on-axis) and
orphan afterglows. Results show that for on-axis GRBs, less than 10 detections
in five years of foreseen Gaia operational time are expected. The orphan
afterglows simulation results are more promising, giving a more optimistic
number of several tens of detections in five years.
