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Added 1 hour ago
Principal/Sr. Principal Mechanical Engineer
Northrop Grumman
Goleta
…space components and services, launch vehicles and related propulsion systems, missile products, subsystems and defense electronics, precision weapons, armament systems, and advanced…
Added 1 hour ago
Manufacturing Engineer - Level 2 or Level 3
Northrop Grumman
Dulles
Northrop Grumman is hiring a Manufacturing Engineer - Level 2 or Level 3 to to join our team in Dulles, VA . This position is 100% onsite and cannot accommodate telecommute work.
Added 1 hour ago
Principal/Sr. Principal Mechanical Engineer
SP - Space Components
United States
…space components and services, launch vehicles and related propulsion systems, missile products, subsystems and defense electronics, precision weapons, armament systems, and advanced…
Added 1 hour ago
Systems Integration/Test Engineer Sr - E3
Lockheed Martin
Littleton, CO · Littleton
System design and test experience with one or more subsystems or fields outside of Systems Engineering (e.g., Electrical Mechanical, Propulsion, RF, Software, etc.)
Added 2 hours ago
Design Engineer
Safran
Walton, KY
Safran is an international high-technology group operating in the fields of aerospace (propulsion, equipment and interiors), space and defense. Its mission is to contribute sustainably to a…
Added 2 hours ago
Propulsion Engineer II (Analyst)
Quantum Space
CA · Hawthorne, CA · 801 Thompson Ave. Suite 201 Rockville, MD
We are seeking a motivated and technically driven Propulsion Engineer II to contribute to the development and analysis of advanced propellant tanks, pumps, and next-generation spacecraft…
Added 3 hours ago
Project Management, Senior Advisor to the Fleet Maintenance Officer (N43D)
Noblis
Norfolk, VA
Prior service as Chief Engineer, Main Propulsion Assistant, or Damage Control Assistant aboard a commissioned warship.
Added 3 hours ago
Hardware Test Engineer
Matternet
Mountain View, CA
We’re seeking a Hardware Test Engineer to build the electrical and mechanical test capability that proves our hardware works, from board bring-up and mechanism life testing to environmental…
Added 3 hours ago
TS
Mechanical Engineer II
Turion Space
Irvine, CA
- $100,000 to $150,000 USD / year
As a Mechanical Engineer, you’ll work across the full development lifecycle from early concept and detailed design through analysis, fabrication, integration, and testing. You’ll…
Added 3 hours ago
TS
Senior Propulsion Engineer, Cryogenic & Chemical Systems
Turion Space
Irvine, CA
- $150,000 to $200,000 USD / year
As a Senior Propulsion Engineer, Cryogenic & Chemical Systems, you will assist the team in the system design, development, integration, testing, and analysis of satellite propulsion…
Added 3 hours ago
Senior Manufacturing Test Engineering, Propulsion
Anduril Industries
Ashville, OH · Costa Mesa, CA
As a Senior Propulsion Test Engineer, you will develop, build, and execute the test campaigns that qualify mission-critical air vehicle propulsion systems and micro-turbojets for…
Added 4 hours ago
M
Hardware Test Engineer
Matternet
Mountain View, CA
- $128,000 to $164,000 USD / year
We’re seeking a Hardware Test Engineer to build the electrical and mechanical test capability that proves our hardware works, from board bring-up and mechanism life testing to environmental…
Added 4 hours ago
Senior Mechanical Engineer – Thermal Analysis (SRM Focus)
Insight Global
Huntsville, AL
Insight Global is seeking a Senior Mechanical Engineer to join a growing Solid Rocket Motor Engineering team. The ideal candidate will possess a strong understanding of thermal analysis…
Added 4 hours ago
Thrust Vector Control Systems Integration & Component Development Hydraulic Engineer (ES4)
Amentum
Huntsville, AL
We are seeking a Thrust Vector Control (TVC) Systems Integration & Components Engineer to support advanced propulsion systems development, integration, testing, and flight operations. This…
Added 4 hours ago
Controls Engineer II
Austal USA
Mobile, AL
REPORTS TO: Program Engineer & Project Department Engineer
Added 4 hours ago
Support Engineer III
INSPYR Solutions
Redmond, WA
Build development focused on Propulsion system assemblies and subassemblies as requested by customers
Added 4 hours ago
A
Propulsion Technician
Aerotek
Redmond, WA
- $38 to $42 USD / hour
Job Title: Propulsion Technician / Support Engineer IIIJob DescriptionThe Propulsion Technician / Support Engineer III assembles propulsion systems and related test equipment in a dynamic,…
Added 4 hours ago
Thermal Engineer I
Relativity Space
Long Beach, CA
…factory, and a business from the ground up. Whether you’re in propulsion, manufacturing, software, avionics, or a corporate function, you’ll collaborate across teams, shape decisions, and…
Added 4 hours ago
Systems Test Engineer 1
United Launch Alliance
Decatur, AL
The ULA Decatur facility is the primary location for building and testing the Vulcan-Centaur rocket. The Systems Test Engineer is a critical role to ensure successful operation of the…
Added 5 hours ago
Dream Chaser Flight Controller (Systems Engineer III)
Sierra Space
Louisville, CO
The Spacecraft Systems Flight Controller serves as the real-time systems engineer responsible for Dream Chaser spacecraft subsystem operations during mission operations. Operating from the…
Added 5 hours ago
Space Flight Dynamics Engineer
The Aerospace Corporation
El Segundo, CA · Chantilly, VA · Colorado Springs, CO · Albuquerque, NM
Analysis of vehicles with chemical and/or electric propulsion
Added 5 hours ago
Sr Data & Control Systems Engineer
Relativity Space
Stennis Space Center, MS
…factory, and a business from the ground up. Whether you’re in propulsion, manufacturing, software, avionics, or a corporate function, you’ll collaborate across teams, shape decisions, and…
Added 5 hours ago
SD
1791 - Computer Engineer
Sigma Defense
Norfolk, VA
- $130,000 to $145,000 USD / year
Sigma Defense is seeking a Computer Engineer to join our team in Norfolk, VA. The hired candidate will serve as the senior technical authority responsible for architecting, implementing,…
Added 5 hours ago
Lead, Systems Engineer
L3Harris Technologies
West Palm Beach, FL
The Missile Solutions segment of L3Harris is a leader in the design, manufacture, and deployment of advanced propulsion and energetics systems, including those for rocket motors. Our…
Added 5 hours ago
Senior Power Electronics Engineer
HX5LLC
Brook Park, OH
Senior Power Electronics Engineer Electrical Engineer V NASA Glenn Research Center Brook Park, Ohio HX5 is an award-winning provider of engineering, research and development, and technical…

Fluidstack

Mechanical Engineer, Thermofluids

Austin, TX, United States
San Francsisco, CA, United States
Los Angeles, CA, United States

$210,000 to $260,000 USD / year

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Job details

Pay: $210,000 to $260,000 USD / year
Experience: 10+ years of experience in thermofluids engineering, including thermodynamic cycle modeling, heat exchanger design, and high-pressure fluid system design.
Posting language: English
Posted: Oct 29, 2026

Original job description

ABOUT FLUIDSTACK

We exist to make humanity more free. For most of human history, you farmed or you starved. Technology gave people more time for the things they wanted to do, instead of things they had to do. Powerful AI will be the biggest lever for human choice we've ever built - but only if models are aligned with what humanity actually wants. There are groups building AI who don't share these goals. Whoever deploys frontier compute infrastructure fastest will decide whether AI expands human freedom or shrinks it.

We're singularly focused on delivering 10 to 100s of GWs of compute faster than anyone else, rethinking every layer of the stack. We acquire power, design and build data centers, and operate them - with teams spanning hardware and software. Speed and scale are our key differentiators. Come be a part of building civilization-scale infrastructure for AI.

We hire people who care deeply about this problem space. If that is you, please apply!

HOW WE OPERATE

Be a barrel. Full autonomy. Own things end to end, take on scope without being asked, no permission required to operate outside your core role.
Insane urgency. We drive everything forward as fast as possible.
Reason from first principles. Challenge every assumption. Zero analogy thinking, no egos, the best idea wins.
Love of the game. The frontier of AI is the most interesting problem of our time. We put in long hours at high intensity to push the frontier forward.
Build something that actually matters. If you're going to spend your time, spend it on something that matters to the world.

THE THERMOFLUIDS R&D TEAM

Examples of key problems the team is working on

Reject 10s of GW of heat, starting now. Fluidstack is targeting 10s of GW of compute over the next two years. Every watt of it becomes heat that has to go somewhere, and no cooling team has ever been asked to open at that scale rather than grow into it.
Design and build the machines, because nobody can supply them. The merchant compressor market cannot deliver at this rate, and the vendor base behind today’s chillers will not scale to gigawatts. We are taking compressor and chiller design in house, working on machine architectures nobody sells today, and going from blank sheet to production faster than this industry thinks is possible.
Own every thermofluids problem behind the fleet, not just the chiller. Working fluid and cycle architecture, heat exchangers at a scale that dominates the cost of the plant, two-phase heat transfer at the chip, and thermal energy storage. All of it is open, and whatever this team lands gets built thousands of times.

ROLE SCOPE

Define what the machine has to be, owning the cycle model that sets the working fluid and the pressures, temperatures and flows the compressor, turbine and exchangers are designed against.
Design heat exchangers with surface areas running into millions of square meters, among the largest single drivers of a data center’s physical footprint.
Design the fluid system around the machine: piping, valves, headers, relief and isolation, sized against the pressure-drop budget the cycle can afford and the pressures the fluid actually runs at.
Run the trades that decide the machine: air-side temperature rise, face velocity and subcooling. Derive the operating points from coupled exchanger ratings rather than asserted approach temperatures, so infeasible designs get caught in the model instead of in hardware.
Take the cycle predictions onto the test stand and reconcile them against measured COP, then say plainly where the model was wrong.

WHAT WE'RE LOOKING FOR

The below is a starting point. We always make space for exceptional people, so if you don't fit this role exactly, tell us where you would https://jobs.ashbyhq.com/fluidstack/05c2e69c-42f9-4fcb-9cf0-a467aaf98f1c.

10+ years of experience in thermofluids engineering, including thermodynamic cycle modeling, heat exchanger design, and high-pressure fluid system design.
You’ve built a thermodynamic cycle model from fluid properties up and defended its assumptions to someone actively trying to break it.
You’ve sized real heat exchangers against published correlations, and you’ve caught a case where the correlation belonged to a different geometry than the one in front of you.
You’ve calibrated a model against a machine datasheet or test data and reported the gap honestly rather than tuning until it disappeared.
You’ve written the analysis that changed a design decision, in a form that people who never ran the code could read and act on.
You’ve sized a relief path and been the one who signed off that the system was protected.
You’ve held a result open when it was still open, instead of closing it early to be helpful.
You're comfortable with regular travel: expect 25% or more, depending on business needs.
Most of our engineering team, stakeholders, and work are based in Austin, TX, and we value working in person. We have a strong preference for Austin and run a hybrid model, but we're open to other locations for the right role and candidate.
Bonus: Vapor-compression and transcritical cycles (chillers, heat pumps, refrigeration). Propulsion and cryogenic fluid systems (feed systems, regenerative cooling, two-phase transport). Piping and relief design for high-pressure fluid systems. Real-gas properties and two-phase heat-transfer correlations (CoolProp, REFPROP, Cavallini, Gnielinski, Wang). Data center thermal architecture (CDUs, dry coolers, direct-to-chip).

We are committed to pay equity and transparency.

Fluidstack is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability and protected veterans’ status, or any other characteristic protected by law. Fluidstack will consider for employment qualified applicants with arrest and conviction records pursuant to applicable law.

Applicant Privacy Notice https://fluidstack.io/legal/applicant-privacy-notice AI Screening Notice https://fluidstack.io/legal/ai-screening-notice Ashby Bias Audit https://fluidstack.io/legal/ashby-bias-audit

You will receive a confirmation email once your application has successfully been accepted. If there is an error with your submission and you did not receive a confirmation email, please email careers@fluidstack.io with your resume/CV, the role you've applied for, and the date you submitted your application-- someone from our recruiting team will be in touch.

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