  SpaceX recently proposed to orbit 19,440 Starlink internet satellites at a
low altitude of 350 km instead of the current 550 km. The distribution in the
sky and the apparent magnitudes of these spacecraft are simulated in this
paper. During astronomical twilight the impact of spacecraft at 350 km on
astronomical observations would be more severe than those at 550 km. However,
during the hours of darkness those at 350 km would have a less severe impact.
The qualitative statement made by SpaceX to the US Federal Communications
Commision is consistent with the quantitative results reported here.
