AMPAC-ISP is a leader in the development and manufacture of liquid rocket engines, tanks and propulsion systems for commercial military launch vehicles and spacecraft, serving international customers. AMPAC-ISP was formerly the liquid propulsion division of Atlantic Research Corporation. It was acquired by AMPAC in 2004 and maintains product development, manufacturing and test facilities in Niagara Falls, New York, and Westcott, United Kingdom (AMPAC-ISP UK Limited). AMPAC-ISP is the largest provider of bipropellant attitude control system engines in the world.

AMPAC In-Space Propulsion (ISP)
AMPAC-ISP designs and builds in-space propulsion systems, thrusters and propellant tanks.

AMPAC-ISP UK Limited
AMPAC-ISP UK Limited manufactures liquid rocket
engines and has capabilities in machining and welding specialty metals.