SPAM - concreting in space

> That would make a near sun location my first choice were it is
> possible, to use direct sun irradiation to heat up the concrete. For
> instance using black painted forms for the parts of a bernal sphere
> and than place it in a appropriate distance to sun to get the positive
> overall temperature .
In space you can have any temperature you want, within reasonable limits. If you want low temperatures, use a sun shade. If you want heat, concentrate the sunlight with parabolic mirrors. If you want more heat, use a bigger mirror, or more than one.