This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the transport of calcium. ATP + Ca(2+)(in) + H2O = ADP + Ca(2+)(out) + H(+) + phosphate Expressed from 4 hours and peaks at 9 hours after onset of sporulation. Spores are less resistant to heat and germinate at a slower rate. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IIA subfamily.