ABOUT POSEIDON AEROSPACE: Poseidon Aerospace is reimagining how the world moves goods. We build and operate full-size autonomous cargo aircraft - capable of carrying two tons of payload over a thousand nautical miles. From remote communities to contested logistics operations, our platforms unlock a new cost curve for air freight, making it faster, cheaper, and accessible anywhere it's needed. Headquartered in the San Francisco Bay Area with locations in Washington DC, Oregon, and Maine; we're building something consequential. ABOUT THE ROLE Test and Validation finds problems on the ground before they show up in flight. As a Test and Validation Engineer you will build and run the hardware-in-the-loop benches, simulation environments, and automated validators that every flight software release and every piece of avionics hardware must pass before it goes on the aircraft. You will also design and run environmental and durability tests on aircraft hardware. The faster you find faults, the faster the aircraft flies. RESPONSIBILITIES - Bring up and maintain hardware-in-the-loop benches with flight computers, actuators, sensors, and power hardware in the loop - Maintain the software-in-the-loop environment and the real-time simulation that drives the benches - Integrate vehicle, sensor, and actuator models from GNC and flight sciences into the simulation - Write validators: automated checks that evaluate simulation, bench, and flight data against requirements - Build automated regression testing that runs each flight software release through simulation and hardware-in-the-loop - Develop fault injection for sensor, actuator, data bus, and power failures - Build data pipelines and analysis tooling for test and flight data - Design and run environmental and durability tests on aircraft hardware, including vibration, thermal, and ingress - Integrate instrumentation and data acquisition on test rigs - Write test plans and procedures from requirements and failure mode analyses, and report results - Investigate anomalies found in test and drive root cause with the owning team - Support aircraft ground test and flight test with validators and data analysis, including travel to our flight test site REQUIRED QUALIFICATIONS - B.S. in electrical, mechanical, aerospace, or computer engineering, or a related field, or equivalent experience - 2+ years testing complex electromechanical or embedded systems - Proficiency in Python and working knowledge of C or C++ - Experience building or operating hardware-in-the-loop, software-in-the-loop, or automated test systems - Hands-on electrical debugging skills and familiarity with common vehicle data buses PREFERRED QUALIFICATIONS - Test experience on aircraft, UAS, spacecraft, or automotive systems - Experience with real-time simulation platforms such as Speedgoat, dSPACE, or NI - Experience with environmental testing to DO-160 or MIL-STD-810 - Experience with actuators, motor controllers, or power systems - Experience with continuous integration for embedded software - Familiarity with FMEA and reliability analysis - Experience analyzing flight or vehicle test data WHY THIS ROLE Every flight software release and every avionics box passes through what you build before it reaches the aircraft. You will work with nearly every engineering team, see problems before anyone else does, and directly set how fast the program can fly safely. WHAT YOU GET FROM US - Competitive salary and meaningful early-stage equity - Relocation support if applicable - Employee Health Benefit Plans - 6% Retirement matching - Flexible PTO - Free lunches, snacks, and a stocked fridge at our offices - AI tools and subscriptions