Mechanical Engineer - Active Cooling

Cowboy Space Corp.

1d•$100,000 - $300,000•Onsite

About The Position

Cowboy Space Corp. is building the infrastructure to power and connect the orbital economy. Our satellites operate in Low Earth Orbit to collect sunlight and enable a new class of capabilities—from powering on-orbit compute, to transmitting energy via infrared lasers (space-to-earth and space-to-space), powering on-orbit compute to delivering secure, high-bandwidth optical data. By rethinking how energy and data are generated and distributed in space, we’re unlocking entirely new ways to operate both in orbit and on Earth. Founded in 2024 by Baiju Bhatt (co-founder of Robinhood), Cowboy Space Corp. is backed by leading investors and built by a team from top aerospace and defense organizations. We’re moving quickly to solve complex technical challenges and build a new category of space infrastructure. As a Mechanical Engineer – Active Cooling, you will be the responsible engineer for the liquid cooling loop that keeps our on-orbit GPU compute hardware temperature controlled. This is a hands-on role that sits at the intersection of fluid systems and mechanical design. You will architect the pumped coolant loop, select and size its component (pumps, valves, accumulators, cold plates, instrumentation, etc) and own the mechanical packaging, structures, and interfaces that integrate it into the spacecraft. You will own this hardware end to end, from concept and analysis through the ground testbeds used to prove it out, qualification, and on-orbit operation. You will work closely with thermal, power, structures, avionics, propulsion, and software teams to deliver an integrated cooling solution. We’re looking for a strong fluids background paired with strong mechanical design skills. Someone who can move quickly, iterate often, and take full ownership of hardware that directly determines whether our compute payload survives and performs in orbit.

Requirements

BS or MS in Mechanical Engineering, Aerospace Engineering, or a related field
3+ years of experience designing or analyzing fluid systems and/or mechanical hardware in aerospace, automotive, energy, data-center cooling, or other high-performance environments
Strong fluids fundamentals: compressible/incompressible flow, thermodynamics, heat transfer, and pressure systems
Hands-on experience with fluid components including pumps, valves, regulators, tubing, and instrumentation
Experience taking hardware from concept through build and test, with hands-on integration and test experience
Strong mechanical design fundamentals in mechanics, materials, and thermal systems
Proficiency with CAD (e.g., NX, SolidWorks, or similar)
Experience working in fast-paced, hardware-focused development environments

Nice To Haves

Direct experience designing pumped liquid cooling loops, two-phase cooling, or cold-plate/coolant systems for high heat-flux electronics or GPU/compute hardware
Experience designing for space environments (thermal, vibration, vacuum) and background in spacecraft structures, mechanisms, or thermal systems
3+ years of experience with spacecraft, launch vehicle, satellite fluid, or thermal systems
Familiarity with thermal control systems and thermal-fluid coupling at the spacecraft system level
Experience with FEA, thermal, and fluid simulation tools.
Knowledge of aerospace standards (MIL-SPEC, NASA-STD, ECSS) and spaceflight hardware qualification and acceptance margins
Hands-on experience with prototyping, machining, test setups, leak testing, or pressure vessel design
Startup or early-stage hardware experience; comfort operating with significant technical ambiguity

Responsibilities

Own the design of the spacecraft liquid cooling loop for GPU compute hardware from concept through flight, including cold plates, pumps, valves, accumulators, heat exchangers, tubing, fittings, and instrumentation.
Perform pressure-drop, flow, and thermal-fluid analyses to size the loop and predict system behavior across the full mission profile, balancing heat rejection, pump power, mass, and reliability.
Design the mechanical packaging, structures, mounts, and mechanisms that house and integrate the cooling loop, and couple it to radiators and the broader thermal control system.
Design, build, and operate ground testbeds and dev rigs to characterize components, validate the loop, and de-risk the flight design ahead of qualification.
Develop and execute proof-pressure, leak, flow, thermal-vacuum, and qualification/acceptance test programs to verify flight-worthiness.
Author and maintain schematics, drawings, interface control documents, analysis reports, test procedures, and release/configuration records.
Select, size, and integrate coolant loop components to meet performance, mass, and reliability requirements, and work with suppliers to ensure high-quality, scalable production.
Diagnose and resolve cooling-system anomalies during integration and test, applying root-cause analysis and implementing corrective actions.
Partner with thermal, power, structures, avionics, propulsion, and software teams to ensure the cooling loop integrates seamlessly within the overall spacecraft architecture.
Embrace a fast-paced development environment, driving quick design cycles, hardware builds, and test campaigns to accelerate the program schedule.