The financial details of the contract, which has a three-year base period and two option years, were not disclosed.
KBR will provide systems engineering, programme management, modelling and simulation, quality, logistics and deployment and other related services for the Patriot missile system.
Work under the contract also includes hardware and software integration, field surveillance, and test and evaluation.
KBR Government Solutions president Byron Bright said: “We have a long history supporting NSPA and we’re proud to continue this trusted relationship.
“KBR’s expertise in cutting-edge research will assist NSPA in responding to today’s dynamic threat environment in multiple theatres worldwide.”
Furthermore, NSPA has requested KBR to conduct studies, engineering evaluations and other investigations.
KBR will carry out work primarily at its facilities in Huntsville, Alabama, and other global US government deployment locations.
Patriot is a long-range, all-altitude, all-weather, advanced surface-to-air guided air and missile defence system used by several Nato countries.
It is designed to counter tactical ballistic missiles, cruise missiles and advanced aircraft.
Patriot is in service throughout the US, Germany, Greece, Israel, Japan, Kuwait, the Netherlands, Saudi Arabia, Korea, Poland, Sweden, Qatar, the UAE, Romania, Spain and Taiwan.
For more than four decades, KBR has been providing advisory and assistance services associated with research and development (R&D), production, deployment, as well as sustainment for the PATRIOT defence system.
Last August, KBR secured a $165m task order for a project within the US Army Program Executive Office Missiles and Space.