Mission Brief 

You will be a senior technical contributor within Combustion Devices, responsible for high-fidelity combustion CFD and the physical understanding required to design, assess and mature liquid rocket engine combustion hardware. You will apply reactive-flow simulation, combustion fundamentals and test correlation to injectors, preburners, gas generators, ignition systems and main combustion chambers, ensuring that designs are performant, stable, thermally robust and ready for manufacture and hot-fire testing. 

Your Role in Our Space Mission: 

• Own and execute CFD analyses of reacting flows in liquid rocket engine combustion devices, from model definition and meshing through solution, verification, validation and technical recommendation. 
• Develop and apply premixed, partially premixed and non-premixed combustion models for rocket-relevant propellant systems and operating conditions. 
• Perform steady and transient RANS/URANS and, where justified, scale-resolving simulations such as LES to investigate mixing, ignition, flame stabilisation, combustion efficiency and unsteady heat release. 
• Model injector and chamber flows including atomisation, evaporation, multiphase effects, real-gas behaviour, conjugate heat transfer and wall heat flux where relevant to the design question. 
• Assess combustion stability and operability, including flame dynamics, pressure oscillations, injector coupling, acoustic interaction, chugging and high-frequency instability risks. 
• Build robust CFD workflows in Simcenter STAR-CCM+ and Ansys Fluent, including geometry preparation, meshing strategies, solver setup, automation, post-processing and model-quality documentation. 
• Correlate simulations against component, cold-flow and hot-fire test data; quantify model uncertainty and clearly define the limits of predictive confidence. 
• Translate CFD results into practical design decisions for injectors, chambers, preburners, gas generators, igniters, cooling concepts and combustion-device interfaces. 
• Work closely with design, thermal, structures, materials, test, engine systems and manufacturing teams to converge combustion-device designs and resolve multidisciplinary issues. 
• Plan analysis and validation activities, review work from colleagues and external partners, and contribute to technical reviews, development roadmaps and risk-retirement plans. 
• Advance combustion modelling methods, engineering standards and reusable best practices across the Propulsion organisation. 

Qualification Checklist 

• MSc or PhD in aerospace engineering, mechanical engineering, chemical engineering, computational engineering or a comparable technical discipline. 
• Typically 5–10 years of professional experience in rocket propulsion, with substantial hands-on responsibility for combustion CFD and combustion-device development. 
• Deep knowledge of fundamental combustion physics, chemical kinetics, flame structure, turbulence–chemistry interaction, ignition and extinction phenomena. 
• Demonstrated experience modelling reactive premixed and non-premixed flows under rocket-engine-relevant pressure, temperature and mixture-ratio conditions. 
• Advanced proficiency in Simcenter STAR-CCM+ and/or Ansys Fluent for complex reacting-flow simulations; strong capability in meshing, solver selection, convergence assessment and post-processing. 
• Strong understanding of liquid rocket engine combustion devices, particularly injectors, preburners or gas generators, main combustion chambers, igniters and associated thermal environments. 
• Experience with CFD verification and validation, mesh and time-step sensitivity, uncertainty assessment and correlation to experimental or hot-fire data. 
• Proficiency in Python, MATLAB or a comparable language for automation, data reduction and engineering analysis. 
• Strong technical ownership, first-principles judgement, clear communication and professional fluency in English. 

Bonus Skills

• Experience with LES or other scale-resolving methods for combustion dynamics, instability and injector–chamber coupling. 
• Experience with spray combustion, atomisation, evaporation, real-fluid or real-gas thermodynamics, conjugate heat transfer, radiation or reacting multiphase flows. 
• Experience supporting rocket-engine hot-fire campaigns, defining instrumentation needs and diagnosing combustion anomalies from test data. 
• Experience developing custom models, user-defined functions, reduced chemical mechanisms, HPC workflows or automated CFD pipelines. 

Benefits 

• Employee Participation Program: Share in our success through our virtual company share program
• 30 days of vacation: Enjoy the days off to relax and recharge
• Company pension plan: Secure your future with our company pension plan, featuring a 20% employer contribution after the probation period
• Subsidised lunch: Stay energised with delicious, subsidised lunches every day
• Rental clothing with laundry service: Enjoy hassle-free workwear with our convenient rental clothing and laundry service  
• Sport Clubs membership: Stay fit with our sponsored sports club memberships (EGYM Wellpass)
• Individual learning allowance: Grow your skills with an individual learning budget granted after the probation period
• Childcare allowance: Receive a childcare allowance for your non-school-age children
• Flexible mobility budget: Travel your way with a choice between a fully financed Deutschlandticket, JobRad bicycle leasing, FINN JobAuto, or a fuel allowance
• And Much More! Discover additional perks and benefits when you join our team 

Who we are

We are Isar Aerospace and we are at the forefront of New Space building a modern space business to enable faster, better and cheaper access to space.

Our mission is to help democratise space and use it for good in order to improve life on Earth now and for the future generations.

We are a fast-growing company aiming to provide sustainable and environmentally friendly launch solutions for small and medium-sized satellites and constellations into Low Earth Orbit. The company is privately funded by world-leading technology investors with strong commitment and support and our team is made of driven and talented people with a real passion for space innovation.

We're making rockets in a way that hasn't been done before disrupting a traditional industry. If you are up for the challenge, want to work on cutting-edge projects and be part of a team changing the world for better, come, join us and launch your career!

Want to find out more about us?

Visit www.isaraerospace.com

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Disclaimer
Isar Aerospace SE is an equal-opportunity employer committed to fairness and inclusivity. We do not prioritize any specific religion, gender, nationality, or background. Due to security clearance requirements, affiliations with countries listed under § 13 para. 1 no. 17 SÜG may affect the application process. All qualified applicants are encouraged to apply.