Catalyzes the condensation of (R)-4-phosphopantoate and beta-alanine to 4'-phosphopantothenate in the CoA biosynthesis pathway. (R)-4-phosphopantoate + ATP + beta-alanine = (R)-4'-phosphopantothenate + AMP + diphosphate + H(+) Cofactor biosynthesis; coenzyme A biosynthesis. Homodimer. Belongs to the archaeal phosphopantothenate synthetase family.