{"id":2985023,"url":"https://alion.io/job/castelion-mission-software-engineer","title":"Mission Software Engineer","company":{"id":1795053,"name":"Castelion","domain":"castelion.com","url":"https://alion.io/company/castelion","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Greenhouse","truth_index":null},"role":"Backend","role_family":"Backend","seniority":"middle","employment_type":null,"work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":[],"countries":[],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":104000,"max_usd":205000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":1539},"experience_years_min":3,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"C++","optional":false},{"name":"CI/CD","optional":false},{"name":"Git","optional":false},{"name":"MIL-STD-1553","optional":false},{"name":"Python","optional":false},{"name":"Rust","optional":false},{"name":"Linux","optional":true},{"name":"Protobuf","optional":true}],"status":"live","first_seen_at":"2026-09-28T18:56:06Z","employer_posted_date":"2026-09-28","last_verified_at":"2026-10-28T16:15:11Z","board_verified":true,"closed_at":null,"days_open":29,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":29},"description":"Why Castelion, Why Now \nCastelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability. \nThis is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function. \nMission Software Engineer\nCastelion is seeking a Mission Software Engineer to build the software that connects our products into an integrated mission capability.\nMission Software spans Castelion’s full product portfolio, including weapons, launchers, command-and-control systems, sensors, mission planning tools, and external platforms. Engineers on this team build the software that allows operators and systems to plan missions, exchange targeting and sensor data, command assets, initialize and employ weapons, and execute missions end to end.\nThis is a hands-on software engineering role. You will design, write, review, test, and commit production code to Castelion’s software stack while working closely with flight software, avionics, guidance and navigation, systems engineering, test, and integration teams.\nThe work crosses traditional software boundaries. You may be developing mission planning software, integrating a tactical C2 interface, building services that move targeting data between systems, debugging communication between a launcher and weapon, or supporting an integrated flight test.\nCore Responsibilities\nDesign, develop, test, and deploy production software supporting weapons, launchers, C2 systems, sensors, and mission planning.\nDevelop and integrate command-and-control software connecting operators, sensors, weapons, launchers, tactical networks, and external platforms.\nBuild APIs, services, and data pipelines that move targeting, mission, telemetry, and system-state data throughout the mission architecture.\nDevelop software interfaces between Castelion products and aircraft, launchers, mission computers, fire-control systems, sensors, and government C2 systems.\nImplement communications across interfaces and protocols such as Ethernet, TCP/UDP, CAN, MIL-STD-1553, MIL-STD-1760, and other tactical interfaces.\nTranslate operational concepts, system requirements, and ICDs into scalable software architectures and working implementations.\nDevelop simulators, tools, and test infrastructure for software-in-the-loop, hardware-in-the-loop, and system-level testing.\nDebug complex issues spanning application software, embedded systems, networks, avionics, sensors, and hardware.\nContribute production code using modern Git-based workflows, code review, automated testing, and continuous integration.\nSupport integration and test activities from laboratory testing through ground and flight test.\nWork directly with government customers, platform partners, operators, and other engineering teams during integration and fielding.\nOwn software capabilities from initial architecture through implementation, test, deployment, and operational use.\nBasic Qualifications\nBachelor's degree in Computer Science, Computer Engineering, Electrical Engineering, Aerospace Engineering, or a related technical field.\n3+ years of professional software engineering experience.\nStrong software development experience in C++, Rust, Python, Go, C, or similar languages.\nExperience contributing to a production software codebase using Git, code review, automated testing, and CI/CD.\nStrong understanding of software architecture, APIs, networking, data serialization, concurrency, and distributed systems.\nExperience developing software that interfaces with hardware, embedded systems, or external services.\nExperience debugging complex integrated software systems.\nAbility to independently take software capabilities from requirements and architecture through implementation and test.\nStrong communication skills and the ability to work across software, hardware, systems, and operations teams.\nAbility to obtain and maintain a U.S. security clearance.\nPreferred Skills and Experience\nExperience developing mission planning, C2, fire control, targeting, autonomy, sensor integration, or weapon-system software.\nExperience with weapons, launchers, aircraft avionics, autonomous systems, spacecraft, robotics, or other mission-critical systems.\nExperience with MIL-STD-1553, MIL-STD-1760, UAI, CAN, Ethernet, TCP/UDP, protobuf, tactical data links, or military mission systems.\nExperience with geospatial software, coordinate systems, targeting, route planning, trajectory generation, or mission-data processing.\nExperience developing software that integrates sensors, shooters, operators, and command-and-control systems.\nExperience with embedded or real-time software.\nExperience developing Linux-based applications and services.\nExperience with SIL, HIL, vehicle-in-the-loop, or flight-test environments.\nExperience supporting complex system-level integration and test campaigns.\nActive Secret or Top Secret clearance.\nAdditional Requirements\nAbility to put in extended hours, including evenings and weekends, when required to meet aggressive timelines\nThis role is based in Torrance, CA and requires full-time onsite presence\nWhat Success Looks Like\nYou will own software that connects Castelion systems across the mission - from sensing and targeting through mission planning, C2, launch, and weapon employment.\nYour work will move from architecture and production code into integrated system test, flight test, and operational fielding. You will help define how Castelion’s products communicate and operate together as a complete mission system.\nCastelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details. \nOther Duties \nPlease note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice. \nAdditional Eligibility Requirements \nThis position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply. \nAffirmative Action/EEO Statement \nCastelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law. \nCastelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact . Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law. \nCastelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation. \nEAR/ITAR Requirements \nThis position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.","description_format":"text","description_chars":8356,"description_truncated":false,"requirements":{"experience_years_min":3,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":{"level":"bachelor","optional":false},"security_clearance":true,"languages":[]},"benefits":[],"hiring_locations":[{"name":"United States","iso":"US","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Missiles","Defense Manufacturing"],"lifecycle":[{"event":"open","at":"2026-10-21T08:14:48Z"}],"visa":[],"liveness":{"score":75,"band":"hot","label":"Hiring now","p_open":1,"p_active":0.836,"p_room":0.9,"age_days":29,"expected_fill_days":46,"reasons":["conf:3","velocity","win:mid","comp:brand"],"computed_at":"2026-10-28T05:59:10Z"},"pay":null,"html_url":"https://alion.io/job/castelion-mission-software-engineer","json_url":"https://alion.io/job/castelion-mission-software-engineer.json","meta":{"generated_at":"2026-10-28T17:19:55Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler_verified","counted_by":"address","units_charged":1,"used_today":23505,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-29T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":1795053},"rest":"https://alion.io/mcp/rest/get_company?id=1795053"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fcastelion-mission-software-engineer"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Fcastelion-mission-software-engineer"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Fcastelion-mission-software-engineer"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/castelion-mission-software-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fcastelion-mission-software-engineer"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":2985023}},{"tool":"search_jobs","arguments":{"company":"castelion.com","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":2985023},"note":"people open to offers who fit this vacancy"}],"note":"The same data through MCP tools: https://alion.io/mcp/open needs no sign-in (compact searches, postings, people); https://alion.io/mcp with an Alion account has everything. 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