Mechanical Engineer, Composites and TPS

The Mission

Space is the infrastructure layer for humanity's next industrial revolution. While reusable rockets have opened the door, true economic transformation requires orbital logistics that are as accessible and reliable as commercial aviation. At Lux Aeterna, we're building that future by developing the first fully reusable satellite platform built for reliable reentry, recovery, and rapid redeployment, transforming space from a one-way street into a two-way highway for innovation and commerce.

The Opportunity

We are seeking a Mechanical Engineer to lead composites and thermal protection system (TPS) engineering on Lux Aeterna's reentry vehicles. Our vehicle structure and TPS systems utilize state of the art composites, metallics, ablatives, and ceramic materials.

You will be the team's authority on composites: laminate and sandwich design, how the parts are made, how they fail, and how to get flight parts from a vendor that match the drawing. You will also be responsible for the vehicle's TPS. If you have designed or built ablative or reusable TPS, we want that experience. If your background is composites and TPS is new to you, you will learn it on our vehicle and take responsibility for it.

This is a mechanical engineering role. As a small team, we don't have distinct design and analysis groups. This role is a mix between design, analysis, and build. You design composite and TPS hardware and write the processes that build it. This is a unique opportunity to:

- Be the composites expert and the TPS lead on a reusable reentry vehicle, from design through flight and refurbishment
- Build Lux Aeterna's composites and TPS process specifications, material data, and test history early in the company's life
- Work hands-on with flight hardware, in our shop and at our vendors
- Work with the mechanical, aerothermal, and thermal engineers and with technical leadership on the decisions that shape the vehicle

Why Lux Aeterna?

- Pioneering Technology: We're developing the first reusable satellite platform with controlled return capability, fundamentally transforming space from a one-way journey to a two-way highway
- Real Impact: Your work will enable new industries in space manufacturing, research, and logistics while pioneering sustainable space infrastructure
- Speed & Autonomy: We maintain parallel hardware development streams and empower engineers to innovate rapidly while upholding rigorous aerospace standards
- World-Class Team: Work alongside experts from leading aerospace companies and research institutions, building technology that will reshape humanity's access to space

The Role

You'll lead composites and TPS engineering on the vehicle, including:

- Designing composite structure and TPS: laminate and sandwich design, inserts, bonded joints, TPS layout, attachment, seams, and closeouts
- Producing fabrication-ready drawings and statements of work for composite parts and TPS
- Writing process specifications for layup and cure, structural adhesive bonding, TPS bonding, and nondestructive inspection
- Selecting materials and building design allowables: coupon test plans, test vendors, and test results
- Managing TPS vendors, and supporting composite vendors, from quote through first article, including tooling, cure, inspection, and rework
- Supporting build in our shop (layup, bonding, potting, TPS installation, and bakeout) with work instructions technicians can follow
- Qualifying materials for spaceflight: outgassing (ASTM E595), vacuum bakeout, and thermal and structural testing
- Working with the aerothermal and thermal engineers on TPS sizing, material properties, and bondline temperature limits
- Leading nonconformance investigations and root cause analysis on composite and bonded hardware
- Defining how composite structure and TPS are inspected, repaired, and refurbished between flights

Required Qualifications

- BS in Mechanical or Aerospace Engineering (or related)
- 7+ years of experience designing and building composite hardware for aerospace or other high-performance applications
- Hands-on experience with prepreg layup, autoclave and out-of-autoclave cure, honeycomb sandwich structure, inserts, and secondary bonding
- Experience taking composite parts through a vendor to delivery: drawings, statements of work, tooling, first article, and nonconformance disposition
- Working knowledge of laminate analysis, composite failure modes, and coupon testing to ASTM standards
- Experience with structural adhesives and surface preparation for bonding
- Experience using 3D CAD software to produce fabrication-ready designs (Siemens NX preferable, but not required)
- Clear written communication: specifications, work instructions, and test reports that technicians and vendors can work from
- Demonstrated ability to operate effectively in a fast-paced engineering environment with shifting priorities

Desired Experience

- TPS design, installation, or test: ablative tiles, flexible ceramic insulation, or high-temperature coatings, including bonding, gaps, and seam closeouts
- Hot structures and structures subject to reentry environments (reentry vehicle, capsule, or hypersonic hardware)
- Spaceflight materials qualification: outgassing (ASTM E595), vacuum bakeout, thermal cycling, and thermal vacuum
- High-temperature resin systems (cyanate ester, BMI) and high-modulus carbon fiber
- Nondestructive inspection of composites and bonded joints (ultrasonic, tap test, thermography)
- Writing material and process specifications
- Early-stage startup experience

We are based in Denver, CO and believe in the power of in-person collaboration. We are onsite 5 days/week by default, but flexible when life requires it.

Compensation & Benefits

The anticipated base salary range for this position is $150k-$225k per year. Actual compensation will be determined based on factors including experience, qualifications, skills, and job-related responsibilities.

This position is also eligible for equity compensation, as applicable.

Lux Aeterna offers a benefits package of medical, dental, and vision insurance; paid time off and company holidays; and a 401(k) retirement plan.

How and When to Apply

Please apply at https://luxaeterna.applytojob.com/apply

Application Deadline: November 9, 2026

Certain roles may involve access to export-controlled technical data. To comply with U.S. export-control laws, access may be limited to individuals who qualify as a "U.S. person" under 22 C.F.R. §120.62 or who otherwise may lawfully receive such access.