Command headquarters is located at Aberdeen Proving Ground, Maryland.

The decision led to the redesignation of the Operational Test and Evaluation Command to ATEC on 1 Oct. 1999.

[2] ATEC conducts testing for all branches of the military and maintains a large customer base that includes the National Security Agency, Joint Chiefs of Staff, allied foreign countries, and Congress.

ATEC employs approximately 9,000 military, civilian and contract employees that are highly skilled test officers, engineers, scientists, technicians, researchers, and evaluators.

ATEC is involved in more than 1,100 tests daily that encompass everything from individual weapons to National Missile Defense systems.