Seeking an experienced Senior Systems Engineer for onsite work in Marlborough, MA, supporting advanced communication systems in aerospace and defense. The role involves leading full lifecycle development, system integration, testing, and validation of ground and airborne communication solutions, including SATCOM and LOS systems. Candidates must hold an active Secret security clearance and U.S. citizenship, with at least 5 years of relevant experience or an advanced degree with 3 years. Preferred experience includes communication radio systems, environmental testing, system IV&V, and proficiency with modeling tools. The position offers comprehensive benefits, relocation assistance, and opportunities to contribute to mission-critical projects in a dynamic environment. Candidates should demonstrate strong communication skills and the ability to influence decision-making across teams. The role is key to supporting complex aerospace missions and ensuring system performance and security.