Sr. Principal Software Engineer
Date Posted: 2026-08-11 | Location: Pelham, NH (US-NH-PELHAM-PE1, 50 Bush Hill Rd, BLDG 1) | Onsite role | Active and transferable U.S. government-issued Secret security clearance required prior to start date. U.S. citizenship is required.
About the Role
RTX, the world's largest aerospace and defense company, is seeking a Senior Principal Software Engineer to join the National Advanced Surface-to-air Missile (NASAMS) program within the Missile Defense Sensors (MDS) software department. The department provides world-class Missile Defense and Surveillance Radar Software for radar and effector systems deployed on land and sea. Our software teams use Agile Scrum and DevSecOps processes to rapidly design, code, and integrate capabilities into a mature solution for our customers.
Responsibilities
- Work with external partners to design interfaces across distinct products.
- Interpret requirements, design, code, test, and integrate new features in C.
- Lab configuration and maintenance, including maintaining configurations, monitoring status, and updating software.
- Attend Software Review Boards (SRBs) and Change Control Boards (CCBs).
- Perform analysis of data received from systems and/or test events.
- Support the execution of all new business development activities.
- Collaborate with systems engineers, integration and test engineers, and other stakeholders to define system requirements and ensure seamless integration of software components.
- Represent the software team in program-level discussions, providing technical expertise and ensuring alignment with program objectives.
Requirements
- Bachelor’s Degree in Science, Technology, Engineering, or Mathematics (STEM) field and typically 10 years of relevant experience. An advanced degree may count for additional years of experience.
- Experience with C and/or C++.
- Experience with Linux, VxWorks, and/or other Real-Time Operating Systems.
- Experience with development of real-time, multi-threaded applications.
- Experience with User Interface/User Experience (UI/UX) design.
- Active and transferable U.S. government-issued Secret security clearance required prior to start date. U.S. citizenship is required.
Preferred Qualifications
- Experience with system-level integration and test.
- Experience with VxWorks Workbench and/or Tornado.
- Experience with Clearcase and/or Git.
- Experience with makefiles and make environments.
- Experience with Windows application development.
- Experience with DOORS or other Requirements Tracking Systems.
- Experience with writing scripts and utilizing Matlab for testing.
- Experience with UDP/IP and TCP/IP networking protocols.
- Prior NASAMS experience.
- Experience interfacing with external partners and leading technical solutions with complex user requirements.
- Experience with subcontract and/or partner management.
- Experience with cost estimation and developing government technical proposals.
- Experience with Software Development in a DoD environment.
- Experience working well independently with little oversight.
- Experience driving creative solutions to complex technical problems in a fast-paced environment.
Pay
The salary range for this role is $132,400 – $251,600 USD. The range provided is a good-faith estimate representative of all experience levels. RTX considers several factors when extending an offer, including role, function, responsibilities, work experience, location, education/training, and key skills.
Benefits
- Medical, dental, and vision insurance.
- Life insurance, short-term disability, and long-term disability.
- 401(k) match.
- Flexible spending accounts.
- Flexible work schedules.
- Employee assistance program.
- Employee Scholar Program.
- Parental leave.
- Paid time off and holidays.
- Eligibility for annual short-term and/or long-term incentive compensation programs (dependent on role level and collective-bargaining agreement status).