**MANTECH** seeks a skilled and motivated **Propulsion Systems Project Engineer** to support the U.S. Space Force Space Systems Command (SSC), Launch Enterprise Directorate (SMC/LE), in executing the National Security Space Launch (NSSL) Program. This position is located in **El Segundo, CA.** You will play a pivotal role in validating launch vehicle propulsion systems—ensuring these systems meet mission needs and are ready to safely and reliably deliver critical National Security Space (NSS) payloads. This position offers the opportunity to contribute to groundbreaking missions involving new launch vehicles such as ULA’s Vulcan and SpaceX Falcon systems. **Responsibilities include, but are not limited to:** As a Propulsion Systems Project Engineer, you will support launch vehicle propulsion system integration and readiness across design, manufacturing, and launch operations phases. + Provide systems and technical project engineering support for both recurring and non-recurring design validation of launch vehicles used in NSSL missions + Participate in propulsion system design reviews, working groups, and Engineering Review Boards (ERBs); assess propulsion component test plans and review completed technical documentation for quality and completeness + Collaborate across multidisciplinary teams including Contractors, Vendors, FFRDCs, and Space Force stakeholders; contribute to risk and schedule management processes + Support rehearsals, launch operations, and anomaly resolution; prepare certification and training material and document lessons learned + Contribute to the development and evolution of Day of Launch tools, CONOPs, and technical processes + Conduct integrated technical assessments of launch vehicle and pad design, testing, manufacturing, and operations; manage engineering data, perform data mining, and deliver technical reporting + Plan, coordinate, and present briefings at Chief Engineer Review Boards and interface regularly with Aerospace Corporation, Launch Service Providers (LSPs), and factory and launch site teams **Minimum Qualifications:** To be successful in this role, you will need: + Bachelor’s degree in mechanical engineering, Aerospace Engineering, or other STEM discipline + 10+ years of experience in aerospace or mechanical engineering fields, with at least 3 years in NSSL, Launch/Range, DoD, NASA, or equivalent launch systems engineering roles + Proven expertise in launch vehicle propulsion systems and component-level assessments + Strong initiative, proactive problem-solving, and the ability to work effectively in a fast-paced, cross-functional environment + Familiarity with MS Office tools (Word, Excel, PowerPoint, Project), SharePoint, and information system databases + Proficient in Confluence and Jira platforms + Demonstrated ability to conduct design reviews, support failure analysis efforts, and collaborate across design, test, and operations disciplines **Preferred Qualifications:** Candidates with the following qualifications will be preferred: + Prior launch console experience providing technical expertise during live launch operations + Previous experience supporting SMC (now SSC) or other U.S. Government space agencies + Strong analytical thinking, interpersonal communication, and organizational skills + Strong written and verbal communication skills with the ability to present technical findings to senior stakeholders + Prior military or launch vehicle systems experience **Clearance Requirements:** + Must be able to obtain and maintain a Department of Defense Secret clearance **Physical Requirements:** + Must be able to remain in a stationary position for 50% of the time. + Needs to occasionally move about inside the office to access file cabinets, office machinery, etc. + Constantly operates a computer and other office productivity machinery. ManTech International Corporation, as well as its subsidiaries proactively fulfills its role as an equal opportunity employer. We do not discriminate against any employee or applicant for employment. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran. If you are a qualified individual with a disability and require a reasonable accommodation to apply for a position with ManTech through its online applicant system, please email us at careers@mantech.com and provide your name and contact information.