For a much smaller Death Star, most of the problems with the Dyson sphere go away. The 13.2 km diameter reactor core would only require a mass 370 times less than our moon's.

The 13.2km diameter reactor core would only require a mass 370 times less than our moon's. ... The pressures involved inside our Death Star reactor would be immense.

For a much smaller Death Star, most of the problems with the Dyson sphere go away. The 13.2km diameter reactor core would only require a mass 370 times less than our moon’s.