ATK [ATK] executives said the company reached an agreement in principle to acquire PSI Group, a manufacturer of satellite components and propellant tanks. According to ATK, PSI provides mission-critical components to the emerging needs of the U.S. military, including next-generation global positioning, navigation and communications satellites. The transaction should close in mid-August, pending federal regulatory review and approval, and ATK will end up with all PSI Group companies, including Pressure Systems Inc., Programmed Composites Inc. and Able Engineering Co. Inc.