Thermal Engineer

**About the role** You'll be our first thermal engineer and the person responsible for the thermal architecture of Spark-1, a 150 kg reentry vehicle that hosts payloads in orbit and brings them back to Earth. This is a founding role. You'll decide where heat goes on the vehicle: which surfaces radiate, how heat moves from the electronics and payloads to those surfaces, what gets heaters and what gets isolated, and how the architecture holds up across orbit cases, safe mode, and reentry.

At our stage that means you build the models, set the requirements, and then put the hardware in the chamber yourself. You'll work directly with the founders every day. **Responsibilities** - Define the spacecraft thermal architecture and carry it from trade studies through CDR and into flight - Build and own the vehicle thermal model in Thermal Desktop, Simcenter Space Systems Thermal, or ESATAN-TMS - Design the thermal control hardware, including heaters and control zones, radiators, MLI, coatings, straps, and the conductive paths through structure - Define payload thermal interfaces and the thermal section of the payload user's guide - Work the couplings with the other subsystems, since attitude drives the sun cases, the power budget drives dissipation, and the heat shield sets the reentry boundary - Plan and run thermal balance and thermal vacuum tests, correlate the model, and carry the margins to flight **Required qualifications** - 3+ years in spacecraft thermal engineering on flight or flight-relevant programs - You have owned the thermal architecture of a spacecraft or a major subsystem, and can explain the trades you made and how they held up - Proficiency in Thermal Desktop, Simcenter Space Systems Thermal, or ESATAN-TMS, with a model you built that flew or went through thermal vacuum - Thermal balance and thermal vacuum test experience, including correlating the model afterward - Comfortable with the hardware, so heaters, thermistors, blankets, straps, and interface fillers are things you have specified and installed - Comfortable working across disciplines at an early-stage company - Must be a US person.

US export control (ITAR/EAR) requires this. **Nice to have** - Reentry vehicle or capsule thermal experience, including heat shield bondline and structure temperatures - Two-phase systems such as loop heat pipes, pumped loops, or deployable radiators - Thermal design for high dissipation electronics - Flight heritage on a small team where you were the only thermal engineer