Simulation Engineer

Spacecraft represent the most pressing unmet need across the entire aerospace industry. As more launch vehicles come online and the cost to orbit decreases, more companies launching payloads to space continue to emerge.

For the first time in history, this influx of payload companies combined with reduced launch costs has resulted in a massive increase in need for commercial spacecraft platforms, known as satellite buses. These buses hold the payloads of our customers and are flown on launch vehicles.

Apex manufactures these satellite buses at scale using a combination of software, vertical integration, and hardware that is designed for manufacturing. Our spacecraft enable the future of society: ranging from earth observation to communications and more.

We’d love for you to join us on our mission of providing humankind access to the galaxy beyond our planet.

About the Role

As a Simulation Engineer, you will be responsible for developing closed-loop spacecraft test platforms — such as six degrees of freedom simulation platform (6DOF), software-in-the-loop (SITL) and hardware-in-the-loop (HITL) — and executing simulation testing strategies to validate and verify the performance, functionality, and reliability of satellite systems. Your expertise and attention to detail will play a critical role in ensuring the successful deployment and operation of Apex's satellite buses.

In this role, you will collaborate with multidisciplinary teams of engineers and technicians to design, implement, and integrate realistic test environments using simulation and emulation tools. We are looking for motivated engineers who are eager to solve complex problems with a focus on practicality and scalability, and who thrive in a dynamic, fast-paced environment.

Responsibilities:

Own closed-loop spacecraft simulation platforms from initial design to deployment

Develop and maintain core simulation capabilities such as scheduling, data routing, diagnostics, configuration, and Monte Carlo capabilities

Develop and maintain simulation models, emulators, and hardware/software interfaces with units under test

Collaborate with cross-functional teams to define test requirements, test procedures, and execute tests

Analyze test data, identify trends, and generate meaningful insights for test results and model improvements

Develop tools to automate simulation workflows, enable data analysis, and produce test reports

Debug complex closed-loop interactions between units under test and simulation

Help shape long-term technical architecture and roadmap for our simulation platforms

Qualifications:

U.S. Person status is required as this position needs to access export-controlled data.

Bachelor’s degree in Computer Science, Computer Engineering, Electrical Engineering, Aerospace Engineering, or a related field. Master's degree is a plus.

3+ years of experience developing closed-loop simulation tools e.g. 6DOF, SITL, PITL, HITL

Strong proficiency in programming languages such as C/C++, Rust, Python.

Comfortable operating and developing within Linux environments

Familiarity with standard software development practices, including testing frameworks, Docker, CI/CD pipelines, and agile development

Experience designing, implementing, and validating physics-based simulation models for closed-loop systems

Experience emulating and integrating virtual sensors, actuators, and test equipment with serial interfaces, network interfaces, and conventional I/O interfaces

Experience with data analysis techniques, automation tools, and pipeline development

Strong analytical and problem-solving skills with keen attention to details

Excellent verbal and written communication skills

Proven ability to work independently and take ownership of technical deliverables

Proven ability to work in a fast-paced and dynamic environment while delivering results

Preferred Qualifications:

Experience in aerospace or satellite industry

Knowledge of satellite subsystems such as sensors, actuators, controls, communications, and power

Experience engineering complex systems that require precise timing, deterministic execution, and high performance, such as real-time and HPC systems

Experience developing and maintaining complex build systems, virtual test environments, and CI/CD

Knowledge of embedded Linux operating systems and/or real-time operating systems

#LI-HC1

Why Join Apex?

Apex believes in creating a work environment that you look forward to embracing every day. Our employees love working at Apex, and we want you to love it too. We're a fast-growing startup that has raised more than $500M in funding, and we invest heavily in our people from day one.

What We Offer For Full-time Employees:

Shared upside: Receive equity in Apex, letting you benefit from the work you create

Best-in-class healthcare: 100% company-paid medical, dental, and vision for you and your dependents, plus $100k life insurance at no cost

Comprehensive PTO package to reset and recharge - starting at 15 days vacation, growing to 20+ days annually, plus 10 paid holidays

Competitive 401(k) plan with generous matching - 100% match on first 3%, 50% on next 2%

8 weeks paid parental leave plus childcare reimbursement up to $350/day for work-related travel

Daily catered lunch and unlimited snacks to keep you fueled throughout the day

Vibrant community: Monthly office socials, pickleball tournaments, run club, and gatherings for you and your family

Your dream desk setup and all the tools you need to be your most productive self

World-class Playa Vista office with the benefit of in-person collaboration with amazing coworkers and flexibility to integrate work and life

Real impact opportunity: Work alongside experts from aerospace, new space, and other cutting-edge industries to make a lasting difference

Additional Information:

Compensation ranges are set by role, level, location, and alignment with market data. A candidate's specific level and base pay are determined case by case and may vary with job-related skills, education, experience, technical capabilities, and internal equity. Beyond base salary, full-time hires are also eligible for long-term incentives in the form of stock options, along with medical, dental, and vision coverage and a 401(k) retirement plan.

ITAR Requirements

Apex's work is governed by U.S. export control laws, including the International Traffic in Arms Regulations (ITAR) and the Export Administration Regulations (EAR). To be eligible for this role, applicants must either (1) qualify as a U.S. Person, meaning a U.S. citizen or national, a lawful permanent resident (green card holder), a refugee admitted under 8 U.S.C. § 1157, or an individual granted asylum under 8 U.S.C. § 1158, or (2) be able to obtain the required export authorizations from the U.S. Department of State, the U.S. Department of Commerce, or another applicable U.S. government agency. You can learn more about ITAR here .

Equal Opportunity Employer

Apex Technology, Inc. is an Equal Opportunity Employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. Candidates and employees are always evaluated based on merit, qualifications, and performance. We will never discriminate on the basis of race, color, gender, national origin, ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status.