Mass Properties Engineer

About UsWe're a combat-tested group of engineers, operators, and entrepreneurs who believe America's edge depends on autonomous airpower that's trusted and deployable today not in 2040. Backed by tier-one investors, we've secured the runway - financial, regulatory, and literal - to move at startup speed while tackling a national-security mission that matters. We've structured the company for radical ownership: no silos, no "systems integrator" overhead, just tightly knit mission-focused IPTs that live and breathe the hardware and code they ship.If you thrive where hard-tech ambition meets national-security urgency, you'll build faster here than anywhere else. Let's get after it.Culture That ShipsStrong Core Values, Startup Execution. Integrity, Service Before Self, Excellence, Honor, Courage, Commitment-powered by a bias for action and a "figure it out" mindset.Self-Starters Only. You'll have clear objectives, a blank sheet of paper, and the trust (plus capital) to move fast. Bureaucracy stays out of your way.One Team, No Tourists. Whether you're tuning a control law at 2 a.m. or heat-treating a Ti-6Al-4V spar, everyone sweats the details. We celebrate wins together and own failures together.What's In It for YouMission With a Pulse. Every line of code, bracket, or test you deliver expands the toolbox of the warfighter on Day 1 of a conflict.Resources Without Red Tape. VC speed + DoD customer pull: access to test ranges, flight hours, and operator feedback while retaining startup agility.Career-Defining Upside. Significant equity, best-in-class benefits, and the chance to see your product deliver in months, not decades.The Principal Mass Properties Engineer is a technical role responsible for predicting, tracking, and managing the mass, center of gravity, and inertia of advanced aerospace vehicles. This role requires a dynamic engineer capable of working throughout the development lifecycle from conceptual design and rapid prototyping through design reviews, first flight, and large scale production. The successful candidate will establish mass properties fundamentals as a core systems engineering discipline and serve as the primary point of contact for this function. They will coordinate closely with multidisciplinary engineering teams and suppliers and ensure that air vehicles comply with airworthiness regulations and industry standards.KEY RESPONSIBILITIESProgrammatic LeadershipEstablish and mature mass properties fundamentals and control processes for a large (>80,000 lb MTOW) UAV development program from conceptual design through high rate full scale production.Collaborate across multiple cross-functional teams and suppliers to ensure seamless integration of mass properties management, including technical performance metrics, maturity margins, and weight reduction efforts for overweight systems.Manage and mitigate mass property risks throughout the program lifecycle, assessing the uncertainty and consequences of weight impacts.Provide vital deliverables to internal stakeholders, including accurate, comprehensive status reporting, subsystem weight allocations, and complex CG/weight optimization trade studies.Foster a culture of accountability, collaboration, and continuous improvement.Operational ExcellenceManage aircraft CG within extremely tight tolerances ahead of taxi and flight events, coordinating heavily with fuel and software teams to ensure correct requirements are implemented.Get hands-on with the aircraft by writing procedures for, leading, and executing critical ground tests, including physical aircraft weighing operations, control surface inertia testing, weight on wheels, ground vibration testing (GVT), and fuel tilt testing.Prepare and generate key regulatory and operational documentation, including Form F and official Weight & Balance (W&B) Manuals.Tool Development & Process ImprovementSpearhead the development, evaluation, and integration of mass properties workflows within major 3D CAD and PLM environments (such as CATIA and Siemens Teamcenter).Lead the logic processing and integration of advanced weight analytics software within existing engineering toolsets to streamline the extraction of mass data directly from 3D parametric models.QUALIFICATIONSEducationBachelor's degree in Aerospace Engineering, Mechanical Engineering, Physics, Mathematics, or a closely related STEM field.Experience and Technical SkillsMinimum 5 years of progressive experience in mass properties or weight engineering, with a proven track record of taking complex aerospace vehicles through the development lifecycle to first flight and production.Deep understanding of weight and balance principles, coordinate system transformations, and the calculation of 3-axis centers of gravity, moments, and products of inertia.Expertise in 3D CAD, PLM, and mass properties data tracking software, specifically Siemens Teamcenter, CATIA, and Excel.Direct, hands-on experience conducting aircraft weighing operations, spin balance testing, and physical inspections on the factory floor or at test sites.Exceptional communication and cross-functional leadership skills, capable of serving as the primary mass properties point of contact for executive leadership, subsystem teams, third party suppliers, and external customers.Ability to thrive in a fast-paced, dynamic environment with competing priorities.Bonus QualificationsBackground in mass properties software development or standing up/integrating commercial weight analytic tools into enterprise PLM systems.Experience or deep understanding of airworthiness certification processes under FAA for 14 CFR Part 25 aircraft.A proven dedication to fostering team development, such as experience with company mentorship programs.Experience in generating Form F documentation, W&B handbooks, and conducting ground tests.WORKING CONDITIONSProfessional office environment with regular meetings and collaborative work sessions.Requires direct hands-on support at test sites and manufacturing facilities during critical integration, ground testing, and flight testing events.Ability to work across multiple time zones to coordinate with the other remote team members across the US.Why You'll Love Working Here (Compensation and Benefits)Base Salary: $155,000 to 235,000 USDThe salary range for this role is an estimate based on a wide range of compensation factors, inclusive of base salary only. Actual salary offer may vary based on (but not limited to) work experience, education and/or training, critical skills, and/or business considerations. Highly competitive equity grants are included in the majority of full time offers; and are considered part of Atropos's total compensation package. Additionally, Atropos offers top-tier benefits for full-time employees, including:Platinum Healthcare Benefits:Atropos offers comprehensive medical, dental, and vision plans with 100% employer-paid premiums and little to no cost to youBasic Life/AD&D and long-term disability insurance 100% covered by Atropos, plus the option to purchase additional life insurance for you and your dependentsUnlimited PTO, with minimum of 15 days enforced20 weeks of paid Caregiver & Wellness Leave to care for a family member, bond with your baby, or tend to your own medical conditionFamily Planning & Parenting Support: Fertility (eg, IVF, preservation), adoption, and gestational carrier coverage with additional benefits and resources to provide support from planning to parentingMental Health Resources: We provide free mental health resources 24/7 including therapy, life coaching, and more. Additional work-life services, such as free legal and financial support, available to you as wellTuition and professional development reimbursement for STEM, MBA, and licensesDaily Lunch cateredCompany-funded child care stipendCompany-funded commuter benefits available based on your region.Relocation assistance (depending on role eligibility).401(k) retirement savings plan - both a traditional and Roth 401(k). 6% employer matching contributionThe recruiter assigned to this role can share more information about the specific compensation and benefit details associated with this role during the hiring process.