Senior Optomechanical Engineer

Location: Onsite — Austin, TX

Employment Type: Direct Hire, Full-Time

Job Title: Senior Optomechanical Engineer

About 9 Mothers

The modern battlefield has changed. Cheap, autonomous suicide drones have turned the tactical advantage upside down, and the world is looking for a solution. At 9 Mothers, we aren’t just "innovating"—we are building the shield.

Backed by top-tier investors, we develop AI powered machines designed to intercept and neutralize Group 1/sUAS threats in real-time. Our flagship product is a low-power, counter-drone system built for the edge—on vehicles, at bases, or in a soldier's pack.

Why 9 Mothers?

While others build for "awareness" or "long-term research," we build for the immediate survival of those in harm’s way. We are a team of hackers, engineers, and mission-driven builders who value field-ready capability over polished slide decks. If you want to see your code or hardware in the field next month—not next year—this is your playground.

Position Summary

• We are hiring a Senior Optomechanical Engineer to own the optics-related subsystems on our robotic weapon platforms: the cameras, thermal imagers, rangefinders, and sensor heads that let our systems find and engage small drones, and the windows, housings, and mounts that keep them working. This role exists because our optics have to hold alignment and image quality on a machine that fires shotguns, slews hard, and lives outdoors in Texas heat, dust, and rain.

• This is not an optical design role. Our lens trains are designed by others, inside and outside the company. Your job is everything that happens to those optics once they leave the designer: how they are held, aligned, sealed, kept clean and dry, protected from shock and vibration, and made to perform the same at 0 °F as they do at 140 °F. You are the person who makes sure we get every bit of performance the optical designer put on paper, and you are the person who tells the designer early when a prescription will not survive the mount it needs.

• The person we want thinks in degrees of freedom. You know where an optic is constrained and where it is free to move, how much it will move with temperature and load, and what that does to focus, boresight, and MTF. You have strong opinions on bonded versus clamped versus flexure mounts, and the experience to back them. You know what Invar, titanium, and stainless buy you over aluminum, and you know when aluminum is the right answer because the error budget allows it and the price does not.

• This is a hands-on role. You will build and align your own assemblies, put them on the shaker and in the thermal chamber, take them to the range, and measure what moved.

Essential Duties

• Own the optical subsystems. Be the responsible engineer for every sensor head, camera module, and optical window on the platform, from concept and requirements through production and field support. Own the optomechanical error budget and the drawings, ICDs, and test procedures that go with it.

• Mount optics properly. Design kinematic, semi-kinematic, flexure, bonded, and retained mounts for lenses, windows, mirrors, filters, and focal plane assemblies. Control preload, bond line thickness, and stress birefringence. Make mounts that can be aligned once and stay aligned.

• Choose materials on purpose. Select housing, cell, spacer, and fastener materials to balance CTE match, stiffness, mass, machinability, corrosion, and cost. Run the athermalization math for focus and boresight, and make the cost-versus-stability call with numbers behind it.

• Manage shock and vibration. Design for weapon recoil, gunfire shock, and gimbal slew loads. Drive structural modes away from excitation, specify or design isolation where it helps, and keep line-of-sight jitter and boresight shift within budget. Run modal and structural FEA and correlate it to test.

• Keep it clean and dry. Design sealed, purged, and desiccated housings that keep moisture, dust, and contaminants off the glass for years in the field. Specify seals, breathers, purge and fill procedures, window coatings, and anti-fog and window-clearing approaches. Set up the clean assembly practices and handling procedures our technicians will follow.

• Align and boresight. Develop alignment and co-boresighting methods and fixtures for multiple sensors on a common mount and to the weapon. Make alignment repeatable on a production floor, not just on your bench.

• Work with the optical designers. Turn lens prescriptions into buildable assemblies. Feed tolerance sensitivities and mechanical constraints back early. Support integrated structural-thermal-optical (STOP) analysis where it earns its keep.

• Test and prove it. Plan and run thermal cycling, vibration, shock, humidity, and water-ingress testing on optical assemblies. Measure what moved, in focus, boresight, and image quality, and close the loop into the next revision.

• Make it manufacturable. Work with our machine shop and suppliers on tolerances, surface finishes, and process capability. Qualify optics, coating, and window vendors. Write the assembly and inspection procedures that get us repeatable units.

• Support the field. Go to the range. Watch the sensors under fire. Bring back what you learn.

Requirements

• 10+ years of optomechanical engineering experience, with optical assemblies you designed that shipped and held up in the field, ideally in harsh environments.

• Deep, hands-on expertise in kinematic and exact-constraint mounting. You can explain where every degree of freedom in your mounts goes, and you have designed flexures, three-point and semi-kinematic mounts, bonded cells, and retaining-ring mounts. We will ask you to walk us through mounts you designed and what went wrong with them.

• Strong materials judgment for thermal stability versus cost: CTE matching, athermalization of focus and boresight, adhesives and bond line design, and the real cost and lead-time differences between aluminum, stainless, titanium, Invar, and composites.

• Practical shock and vibration experience: modal analysis, random vibration and shock response, isolation, preload design, and the test methods to verify them (MIL-STD-810 or equivalent). You know the difference between a mount that passes the shaker and a mount that holds boresight after it.

• Experience designing and building sealed optical housings: O-ring and gasket design, dry nitrogen purge, desiccants, pressure equalization, window selection and mounting, and contamination control during assembly.

• Fluency with optical tolerance and error budgets. You can read a lens prescription and drawing, understand which tolerances matter, and translate image-quality and boresight requirements into mechanical requirements.

• Proficiency in FEA (modal, structural, thermal) and the judgment to know when the model is wrong.

• Strong GD&T and drawing skills. Your drawings fully define an optical assembly and suppliers can build to them.

• Hands-on alignment and test skills: autocollimators, collimators, alignment telescopes, interferometry or MTF benches, and building your own fixtures when the right one does not exist.

• A bachelor's degree in mechanical engineering, optical engineering, or physics, or equivalent experience.

• Efficient, low-ego, and easy to work with. You say no clearly when a design will not survive, and you move work forward without drama.

Nice-to-Have

• Experience with weapon-mounted or gun-fire-exposed optics: fire control sensors, weapon sights, remote weapon stations, or gimbaled EO/IR turrets.

• Experience with infrared optics and windows (germanium, ZnS, ZnSe, chalcogenides, sapphire) and their mounting, coating, and thermal quirks. Experience integrating uncooled thermal cores.

• Experience with laser rangefinders or other active optical systems, including transmit/receive boresight.

• STOP analysis experience with tools such as Zemax OpticStudio, Code V, or Sigmadyne SigFit.

• Experience with gimbal and stabilized-platform design, where structural stiffness and line-of-sight stability drive the architecture.

• Experience taking optical assemblies from prototype into rate production, including vendor qualification and production alignment fixtures.

• An interest in firearms and the problems they create for everything bolted to them.

• Experience in a venture-backed hardware startup.

Benefits

• Meaningful Early Equity: You aren't just an employee; you are a foundational owner. Your contributions directly drive the value of your stake in the company.

• Direct Roadmap Influence: Forget the bureaucracy of big defense. You will have a seat at the table, directly shaping our product and technology trajectory from day one.

• Mission-Critical Work: We don't build for "what if." We build systems the Department of War actively needs to counter immediate, real-world threats.

• The Builder's Playground: Work in a brand-new lab fully optimized for rapid prototyping, equipped with NVIDIA Jetsons, high-end scopes, and 3-D printers.

• 100% Employer-Paid Premiums: We cover 100% of your medical, dental, and vision insurance premiums and cover 50% of healthcare premiums for your dependents.

• Unlimited PTO: We value results, not clock-watching. Take the time you need to stay sharp and recharge.

• Zero Red Tape: You have the autonomy to make technical decisions that would take months of committee approval at a larger firm.

• Austin-Based Culture: Join an onsite team in Austin, TX, where we prioritize high-bandwidth collaboration and rapid field-testing.

• Relocation Assistance: We want the best talent in the room. If you aren't in Austin yet, we’ll help you get here, to make your transition to the Silicon Hills seamless.

About the Interview

1. Initial screen with recruiter (30 min phone call)

2. Virtual interview with Director of Hardware Operations (30 min via MS Teams)

3. Onsite interview at our Austin facility (1 hour in-person)