Thermal Systems Engineer in Harwell

At Open Cosmos we are solving the world’s biggest challenges from space, providing businesses, governments and researchers access to more readily available information than ever before. Working in our Chief Technology Office (CTO), the CTO division is where Open Cosmos technology comes to life. Covering engineering, product development, and technical innovation, the team designs, builds, and operates the satellites, systems, and platforms that make our missions possible. It’s a highly collaborative environment where ideas become real hardware, software, and data solutions that deliver impact from space.

Our Systems Team brings together brilliant Systems, AOCS and Thermal Engineers who turn ambitious mission concepts into reality. They design, integrate, and optimise every detail – from spacecraft architecture to next-generation optical payloads – making sure every system fits, works, and thrives in orbit. From first sketch to launch day, they own the journey, ensuring our satellites deliver maximum impact back on Earth.

What You'll Be Doing

• You’ll run the thermal work package for multiple missions, model and analyse spacecraft thermal behaviour, and plan and run thermal tests.
• You’ll work hands‑on during AIT, support anomaly resolution, and be part of the team that ensures Open Cosmos missions perform as expected in space.
• You’ll also collaborate with our other subsystem engineers, feed into our product roadmap, and help us continuously improve how we design and deliver missions.

What You’ll Bring

• Strong knowledge of spacecraft thermal control and space thermal environments.
• Proficiency with thermal modelling tools (e.g. ESATAN-TMS, Thermica, Thermal Desktop).
• Proven ability to plan and deliver thermal tests from start to finish.
• Solid understanding of satellite subsystems and confidence working across disciplines.
• Knowledge of mission analysis and overall space system design.
• Clear communication skills – comfortable engaging with colleagues, partners, and customers.
• A proactive, adaptable approach that thrives in a fast‑moving, growing company.

For this role you can be based in either Harwell, UK, Porto, Portugal or Barcelona, Spain. To apply, you must have the legal right to work in your chosen location. Please submit your application in English.

Why Open Cosmos?

• Work at the cutting edge of space technology with customers around the globe.
• A mission‑driven company making space accessible to help solve real‑world challenges.
• A diverse, ambitious, and supportive team.

Equal opportunity employer: At Open Cosmos, we are dedicated to fostering a workplace built on respect, dignity, and belonging. As an equal opportunity employer, we actively challenge bias to ensure every candidate and employee feels truly welcome. We celebrate diversity in all its forms and are committed to maintaining an inclusive environment where everyone has the opportunity to thrive.