Senior Cryogenic Systems Engineer

Until is a moonshot company building a “pause button” for biology. Our near-term focus is organ-scale reversible cryopreservation: preserving donated organs at subzero temperatures without ice formation, then rewarming them uniformly for transplant. By solving this grand challenge, we’re laying the foundation for whole-body reversible cryopreservation, giving patients a bridge to future cures.

To achieve our goal, we are assembling an interdisciplinary team to develop perfusion systems, cryoprotectant formulations, and vitrification and rewarming hardware.

We envision a future where no transplantable organ is lost to logistics, and no terminal diagnosis is final because patients can safely wait for future medicine to arrive.

About the Role
As a Cryogenic Process & Systems Engineer at Until, you’ll lead design and execution of high-pressure cryogenic fluid systems that support our perfusion and rewarming hardware. You’ll translate process requirements into engineered systems—pumps, piping, heat-exchangers, instrumentation, and safety infrastructure—to enable organ-scale vitrification and rewarming.

You’ll work side-by-side with mechanical engineers, materials scientists, and biologists to build, test, and iterate hardware that pushes the boundaries of cryogenic processing.

What You’ll Do:
• Design, build, and validate cryogenic fluid systems including high-pressure piping, pumps/compressors, valves, manifolds, instrumentation, and insulation.
• Create and maintain process documentation (PFDs, P&IDs), system architecture drawings, and simulation/analysis of thermal/fluid/structural performance.
• Size and select cryogenic and high-pressure equipment, coordinate integration, commissioning, and test of prototypes.
• Perform analyses of pressure drop, NPSH, fluid/thermal behavior, material embrittlement, heat in-leak, and boil-off dynamics.
• Lead safety architecture for cryogenic systems: relief/vent systems, purging strategies, instrumentation, code compliance (ASME/API/NFPA/CGA).
• Develop and run hardware test rigs, collect data, investigate failures, iterate rapidly.
• Collaborate with cross-functional teams (mechanical, thermal, materials, biology) to integrate cryogenic hardware into larger systems.

About You:
• Bachelor’s degree in Mechanical, Chemical, Petroleum or related Engineering discipline.
• At least 3 years of experience working in one or more of these areas: LNG/liquid-gas processing, cryogenic fluids (LN₂/LNG/LOX/LH₂), or high-pressure industrial gas systems.
• Hands-on experience with high-pressure piping, rotating equipment (pumps/compressors), valves and instrumentation in cryogenic or industrial-gas contexts.
• Strong foundation in fluid mechanics, thermodynamics, heat-transfer, material behavior at low temperature / high pressure.
• Comfortable working in a hardware lab environment with prototype development and test.
• Bonus points if you have experience with flow-through or perfusive cooling architectures, process simulation tools (Aspen HYSYS/ProMax), HAZOPs or safety reviews, commissioning or vendor/EPC coordination, or prior work in LNG, industrial gases, aerospace cryogenics, or advanced cooling systems.

Benefits:
• A mission-driven environment tackling one of the hardest problems in medicine.
• The opportunity to build and direct a world-class imaging program from the ground up.
• A deeply interdisciplinary team of scientists, engineers, and builders.
• Generous medical, dental and vision insurance coverage
• Flexible time off and paid holidays
• Competitive compensation package, including salary and equity
• Access to a 401(k) retirement savings plan
• FSA and commuter benefits
• Subsidized lunch daily

As an equal opportunity employer, Until is committed to providing employment opportunities to all individuals. All applicants for positions at Until will be treated without regard to race, color, ethnicity, religion, sex, gender, gender identity and expression, sexual orientation, national origin, disability, age, marital status, veteran status, pregnancy, or any other basis prohibited by applicable law.