Test Engineer - Solar Simulator

Exowatt is revolutionizing the energy landscape for the AI era with our groundbreaking P3 system that captures solar energy, stores it as heat, and generates electricity on demand. Founded in 2023 and backed by leading investors including Andreessen Horowitz, Sam Altman, and Felicis, we're committed to providing clean, modular, and scalable power that meets the rapidly growing demands of AI infrastructure. Our mission is to make sustainable renewable energy always available and almost free, enabling technological advancement while protecting our planet.

We're hiring a Test Engineer to own day-to-day operation of the solar simulator and lead the characterization and validation testing that feeds directly into our product development. This is a hands-on role for someone who likes working with real hardware, high-flux optics, and high-temperature systems — and who gets energized by the fact that the data they generate actually drives design decisions.

Key Responsibilities

Plan, set up, and execute test campaigns on the solar simulator, including thermal receiver characterization, material testing, and sub-system validation

Design and build test fixtures, instrumentation setups, and data acquisition systems to capture high-quality experimental data

Operate and maintain the simulator and supporting lab infrastructure — lamp arrays, optics, cooling, controls, and safety systems

Perform flux mapping, spectral characterization, and calibration to ensure test conditions are well-understood and repeatable

Instrument test articles with thermocouples, pyrometers, flow meters, flux sensors, and related diagnostics

Develop data acquisition and control scripts (LabVIEW, Python, or similar) and automate repetitive test sequences

Analyze test data, identify anomalies, and communicate results clearly to R&D, engineering, and leadership stakeholders

Partner closely with design engineers to translate test findings into design improvements

Write test plans, procedures, and reports; maintain rigorous records of configurations, calibrations, and results

Enforce and continuously improve lab safety practices for high-flux, high-temperature, and high-voltage work

Support troubleshooting and root-cause investigations on prototype hardware

Required Qualifications

Bachelor's degree in Mechanical, Aerospace, Electrical, or a related engineering field

3+ years of hands-on test engineering experience in a lab or prototype environment

Experience designing and executing test plans, including instrumentation selection and test fixture design

Proficiency with data acquisition tools (LabVIEW, Python, MATLAB, or similar) and common lab instrumentation

Strong understanding of heat transfer, thermodynamics, or thermal-fluid systems

Comfort working with high-temperature, high-voltage, or otherwise hazardous equipment, and a demonstrated safety-first mindset

Clear technical writing and the ability to communicate findings to technical and non-technical audiences

Preferred Qualifications

Experience with solar simulators, high-flux testing, or other high-intensity optical systems

Familiarity with thermal receivers, heat exchangers, or high-temperature storage materials

Experience calibrating optical or thermal instrumentation (pyrometers, flux gauges, radiometers)

Background in mechanical fabrication, machining, or hands-on prototype assembly

Previous work in a fast-moving hardware startup environment