  We report a simulation and quantification of the impact of the Starlink
constellation on LSST in terms of the trail surface brightness using a
BRDF-based satellite photometric model. A total of 11,908 satellites from the
Gen1 and Gen2A constellations are used to focus on the interference to the
initial phase of LSST operation. The all-sky simulation shows that
approximately 69.33% of the visible satellites over station have an apparent
brightness greater than 7 mag with a v1.5 satellite model. The impact of
satellite streaks exhibit a non-monotonic relationship to the solar altitude,
with the worst moments occurring around $-15^{\circ}$ solar altitude. The
assessment based on simulated schedules indicates that no trails can reach the
saturation-level magnitude, but 71.61% trails show a surface brightness
brighter than the best-case crosstalk correctable limits, and this percentage
increases as the dodging weight increases. Therefore, avoiding satellites in
the scheduler algorithm is an effective mitigation method, but both the number
of streaks and their brightness should be taken into account simultaneously.
