Senior Software Engineer - Fullstack

Location
Westminster, CO

Please Note: To conform with the United States Government Space Technology Export Regulations, the applicant must be a U.S. citizen, lawful permanent resident of the U.S., conditional resident, asylee or refugee (protected individuals as defined by 8 U.S.C. 1324b(a)(3)), or eligible to obtain the required authorizations from the U.S. Department of State.

At CesiumAstro, we are developers and pioneers of out-of-the-box communication systems for satellites, UAVs, launch vehicles, and other space and airborne platforms. We take pride in our dynamic and cross-functional work environment, which allows us to learn, develop, and engage across our organization. If you are looking for hands-on, interactive, and autonomous work, CesiumAstro is the place for you. We are actively seeking passionate, collaborative, energetic, and forward-thinking individuals to join our team.


We are seeking a Senior Software Engineer to support several new, space-centric programs across the DoW and IC. We are looking for engineers who thrive in a fast-paced startup environment and enjoy solving hard problems. Our culture is simple: work hard, solve real problems, build things that matter.

JOB DUTIES AND RESPONSIBILITIES
- Build modern full-stack applications in support of space mission systems.

- Integrate and modernize legacy space-related ground and flight software.

- Develop distributed applications leveraging microservices, cloud-native architectures, and Distributed Ledger Technology (DLT)/consensus frameworks.

- Support on-orbit and ground system integration & test, including emulation, simulation, and interface validation.

- Implement DevSecOps pipelines, automated testing, and secure software practices.

- Develop modern UI/UX interfaces for mission operators and analysts.

- Work closely with space system engineers, mission integrators, and operations teams.

- Contribute to a mission-focused engineering culture where your ideas truly shape the product.

JOB REQUIREMENTS AND MINIMUM QUALIFICATIONS
- Bachelor’s degree in Software Engineering, Computer Engineering, or relevant field.

- 5+ years of relevant software engineering experience.

- Demonstrated technical leadership across software modernization or distributed systems

- Experience architecting microservices, APIs, message buses, and high-availability systems

- Expertise integrating and testing software for space-based or ground mission systems

- Ability to mentor junior engineers and guide design decisions

- Experience with DoD/IC programs, ATO processes, or DevSecOps on classified systems

- Experience developing in C++, C#, Rust, Python, or Go.

- Experience with SQL/NoSQL database design and integration.

- Experience with cloud services (AWS, Azure, or GovCloud variants).

- Experience with GitHub, Jira, and Confluence.

- U.S. Citizenship is required for this position along with the ability to obtain a Secret security clearance.

- Ability to travel up to 10%.

PREFERRED EXPERIENCE
- Existing security clearance (TS/SCI preferred).

- Experience supporting DoD/IC programs.

- Experience building software for spacecraft, OPS software, or flight/ground segment integration.

- Experience with high-performance computing, distributed processing, or real-time systems.

- Experience with performance tuning and resource-constrained environments.

- Experience with DevSecOps, IaC, and automated test frameworks.

- Familiarity with DLT, blockchain, or consensus protocols.

- Experience with modern UI/UX frameworks (React, Vue, Svelte, Blazor, etc.).

CesiumAstro considers several factors when extending an offer, including but not limited to, the role and associated responsibilities, a candidate’s work experience, education/training, and key skills.  Full-time employment offers include company stock options and a generous benefits package including health, dental, vision, HSA, FSA, life, disability and retirement plans.  
 
CesiumAstro is an Equal Opportunity employer.  All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability, protected Veteran Status, or any other characteristic protected by applicable federal, state, or local law.

Please note: CesiumAstro does not accept unsolicited resumes from contract agencies or search firms. Any unsolicited resumes submitted to our website or to CesiumAstro team members will be considered property of CesiumAstro, and we will not be obligated to pay any referral fees.

Responsibilities

Build modern full-stack applications in support of space mission systems.; Integrate and modernize legacy space-related ground and flight software.; Develop distributed applications leveraging microservices, cloud-native architectures, and Distributed Ledger Technology (DLT)/consensus frameworks.; Support on-orbit and ground system integration & test, including emulation, simulation, and interface validation.; Implement DevSecOps pipelines, automated testing, and secure software practices.; Develop modern UI/UX interfaces for mission operators and analysts.; Work closely with space system engineers, mission integrators, and operations teams.; Contribute to a mission-focused engineering culture where your ideas truly shape the product.

Requirements

Bachelor’s degree in Software Engineering, Computer Engineering, or relevant field.; 5+ years of relevant software engineering experience.; Demonstrated technical leadership across software modernization or distributed systems; Experience architecting microservices, APIs, message buses, and high-availability systems; Expertise integrating and testing software for space-based or ground mission systems; Ability to mentor junior engineers and guide design decisions; Experience with DoD/IC programs, ATO processes, or DevSecOps on classified systems; Experience developing in C++, C#, Rust, Python, or Go.; Experience with SQL/NoSQL database design and integration.; Experience with cloud services (AWS, Azure, or GovCloud variants).; Experience with GitHub, Jira, and Confluence.; U.S. Citizenship is required for this position along with the ability to obtain a Secret security clearance.; Ability to travel up to 10%.

Nice to have

Existing security clearance (TS/SCI preferred).; Experience supporting DoD/IC programs.; Experience building software for spacecraft, OPS software, or flight/ground segment integration.; Experience with high-performance computing, distributed processing, or real-time systems.; Experience with performance tuning and resource-constrained environments.; Experience with DevSecOps, IaC, and automated test frameworks.; Familiarity with DLT, blockchain, or consensus protocols.; Experience with modern UI/UX frameworks (React, Vue, Svelte, Blazor, etc.).