Senior Thermal Engineer

ALTEN is a global engineering and technology consultancy operating across over 35 countries worldwide. We partner with industry leaders across sectors including Aeronautics, Aerospace, Defence, Naval, Automotive, Energy, Rail, IT and many more to deliver innovative engineering solutions that drive technological advancement & support sustainable transformation.

Our teams of passionate and agile engineers work on cutting-edge projects that shape the future of technology and sustainability. At ALTEN, we empower talented engineers to innovate, solve complex challenges, and deliver impactful solutions that build tomorrow’s world—today.

Join us and start building tomorrow’s world today!

We’re seeking an experienced Senior Thermal Design Engineer to lead the design, analysis, and validation of spacecraft thermal control systems. You’ll play a key role in developing models, defining control strategies, and supporting testing to ensure mission-critical performance and reliability. Working closely with multidisciplinary engineering teams, you’ll help deliver innovative thermal solutions that meet the demanding requirements of space applications.

• Location: London
• On Site: Remote 
• Clearance: SC 
• Experience Level: Mid - Senior 

Key Responsibilities:

• Lead the end-to-end thermal design and simulation process for spacecraft components and subsystems.
• Build and validate detailed thermal models using specialist engineering software.
• Define and implement effective thermal control strategies using both active and passive methods, such as heat pipes, radiators, insulation, and heaters.
• Support all levels of testing, from component evaluation to full spacecraft system trials.
• Plan and oversee environmental qualification tests, including thermal vacuum campaigns, and review results to verify performance.
• Participate in key engineering milestones, design reviews, and technical discussions throughout the project lifecycle.
• Ensure all thermal systems comply with internal standards, performance targets, and customer expectations.
• Work collaboratively with cross-functional teams including mechanical, systems, electrical, and propulsion engineers to ensure seamless integration.
• Provide technical leadership, mentoring less experienced engineers, and encouraging best practice across the team.
• Produce and maintain high-quality engineering documentation, including test procedures, reports, specifications, and technical drawings.

Required Skills:

• Essential: Proven experience working within the space sector, supporting spacecraft or satellite programmes.
• Approximately 10+ years of experience in thermal design and analysis for space applications.
• Proficiency in thermal analysis tools (such as ESATAN-TMS, Thermal Desktop, or similar) and 3D CAD software.
• Strong understanding of heat transfer mechanisms, space environments, and thermal control design principles.
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Required Qualifications:

• A Bachelor’s or Master’s degree in Engineering, or equivalent military experience.

Desirable Skills:

• Ability to work autonomously while contributing effectively in a multidisciplinary team.
• Experience mentoring or technically guiding other engineers is advantageous.
• Experience planning and conducting thermal and environmental testing campaigns.
• Familiarity with flight hardware development and qualification processes.
• Excellent communication, documentation, and teamwork skills.

Why join us? 

We bring together entrepreneurial, tech-driven people to deliver innovative solutions for leading companies.

At ALTEN, you’ll work on exciting projects, supported by ongoing learning, mentoring, and clear career development tailored to your goals.

Join a passionate team and help build tomorrow, today.

In short you get: 

• A personalised career path and a rewarding management style 
• A huge diversity of engineering projects and industries
• Private Medical Insurance
• Cycle & Tech Scheme 
• Employee assistance programme
• Life insurance & Pension Scheme
• Social atmosphere, regular gatherings & team buildings
• Flexible way of working (role dependent)

We are proud to support the Armed Forces Covenant & actively encourage applications from members of the Armed Forces community, including veterans, reservists, service leavers, and military spouses/partners. We recognise the value of military skills and experience and are committed to ensuring that no applicant is unfairly disadvantaged during our recruitment and selection processes. 

ALTEN is committed to fostering a diverse and inclusive workplace and values the strength that comes from a global mix of backgrounds and perspectives. We welcome applications from all suitably qualified candidates, regardless of background or protected characteristics under the Equality Act 2010. If you require any reasonable adjustments during the recruitment process, please let us know. 

This role may require you to have or be willing to go through Security Clearance. As part of the onboarding process candidates will be asked to complete a Baseline Personnel Security Standard; details of the evidence required to apply may be found on the government website Gov.UK. If you are unable to meet this and any associated criteria, then your employment may be delayed, or rejected . Details of this will be discussed with you at interview.