Build Engineer I​/II - Space

About Us

At Antares, our long-term mission is to make clean energy abundant from Earth to the Asteroid Belt. We’re fueled by the belief that advanced nuclear energy can strengthen our military, solve the climate crisis, elevate global living standards, and expand humanity's presence in outer space. To achieve our mission, we’re building mass-producible, inherently safe, deployable microreactors that can be used terrestrially, underwater, and in space.

The Antares team hails from SpaceX, the White House, the Pentagon, the Department of Energy, MIT, Rigetti Computing, General Atomics, Relativity Space, Ursa Major, and National Laboratories like Idaho, Oak Ridge, Los Alamos, and Savannah River. Antares has raised over $600M in venture capital from top-tier investors and has hundreds of million-dollars on contract with the military services, NASA, and the Department of Energy.

As a Build Engineer I/II on Antares’ Space team, you will turn engineering designs into hardware that advances nuclear power for space missions. You will own development, prototype, and pathfinder builds from planning through assembly, testing, and as-built closeout. Working closely with design engineers and technicians, you will solve hands-on integration challenges and develop repeatable build processes that support qualification and transition to production.

• Plan assembly sequences, build flow, and schedules using engineering drawings and CAD models; update models as needed.

• Write build procedures and work orders, maintaining accurate as-built records and hardware configuration throughout each build.

• Assemble mechanical and fluid hardware using appropriate tools, torque specifications, and hardware selections; support design reviews to confirm adequate safety factors and margins.

• Install instrumentation and wiring, perform mid-build checkouts, and support verification, validation, and qualification testing, including test installation, operations, teardown, and post-test inspection.

• Design, procure, and build fixtures, handling equipment, and development tooling.

• Source commercial off-the-shelf hardware, quick-turn machined parts, and consumables; inspect incoming parts and resolve fit or quality discrepancies before assembly.

• Troubleshoot assembly and integration issues, document redlines, and coordinate changes with design owners to preserve requirements, interfaces, and design intent.

• Capture lessons learned and incorporate process improvements into build documentation to support repeatable production and handoff.

• Maintain a safe, organized build area when working with pressurized systems, high temperatures, and heavy hardware.

• Bachelor’s degree in mechanical or aerospace engineering, or a related engineering discipline.

• 1+ years of hands-on experience building, assembling, or integrating mechanical hardware; internships and hardware-focused student projects qualify.

• Ability to read and interpret engineering drawings and 3D CAD models.

• Experience owning a hardware build from planning through completion, including on collegiate rocketry, satellite, or similar project teams.

• Proficiency with geometric dimensioning and tolerancing (GD&T) and tolerance stack-ups.

• 3D CAD experience designing fixtures and tooling;
  Siemens NX preferred.

• Experience writing build procedures, travelers, or work instructions for flight or flight-like hardware.

• Hands-on experience with fluid systems, including tube fittings, valves, regulators, seals, precision cleaning, and helium leak checking.

• Strong understanding of bolted joints, including torque, preload, and thread locking.

• Experience operating manual mills and lathes, with familiarity in welding, brazing, sheet metal…