The Defense Department has formally changed its plans for the first phase of a Strategic Defense Initiative anti-missile defensive system, slashing the cost estimate for a rudimentary system from $115 billion to $69 billion, it announced Thursday. "This is a startling change," top Pentagon officials told a joint hearing of the House and Senate Armed Services Committees. But the lowered cost is the result of changes in the program, the Pentagon said. The changes are designed to keep the research moving forward while addressing concerns that it would cost too much to begin deploying a system on the ground and in space, the Pentagon said.