Solar Radiation
Incident solar flux changes with geometry, orientation, season and mission attitude, creating surface-specific absorbed loads.
Space thermal engineering · MLI · Electronics stabilization
Satellite MLI Insulation and Spacecraft Thermal Control Engineering
Mission-specific thermal engineering for satellites and spacecraft—from orbital hot and cold cases to MLI blanket architecture, electronics stabilization, detailed integration and TVAC-supported verification.
Orbital thermal analysisMLI blanket engineeringElectronics stabilizationTVAC verification support
20+ YearsThermal engineering experience
Vacuum & CryogenicIntegrated thermal-system know-how
Space InfrastructureSatellite test-system experience
End-to-EndAnalyse · Design · Integrate · Verify
Mission-to-hardware thermal engineering
Spacecraft Thermal Control Is a System, Not a Single Insulation Layer
In orbital vacuum, a spacecraft does not reject heat to the external environment through normal atmospheric convection. Its temperature is governed by absorbed solar energy, planetary albedo and infrared radiation, internal equipment dissipation, conduction through the structure and radiation from external surfaces.
Multi-layer insulation (MLI) limits radiative heat exchange across selected surfaces. It does not replace the conductive heat path that transports electronics dissipation to a radiator, nor does it replace heaters required during cold mission modes. MLI, radiators, coatings, interfaces, straps, heat pipes, heaters and sensors must therefore be designed as one thermal-control architecture.
ERATHERM develops this architecture from mission inputs and component limits through analysis, MLI detail engineering, integration documentation and thermal-vacuum verification support.
Core principle: The objective is not to make every spacecraft surface equally insulated. It is to keep each component within its operational and survival limits across every required mission mode.
Orbital thermal environment
Spacecraft Thermal Control in Hot and Cold Mission Cases
A credible satellite thermal-control system is based on orbit, attitude, mission modes and equipment power profiles—not one steady operating temperature.
Albedo & Planetary IR
Reflected sunlight and planetary infrared radiation add orbit-dependent external loads that vary with view and altitude.
Eclipse & Mission Modes
Transitions between sunlight, eclipse, safe mode and operational modes create transient cold and hot conditions.
Internal Dissipation
Avionics, payloads, batteries, RF units and power electronics release different heat loads according to duty cycle.
Integrated heat-flow architecture
MLI Must Be Coordinated with the Heat-Rejection Path
MLI reduces unwanted radiative exchange, while dissipated heat still needs a controlled path from the source to a surface that can reject it to space.
Mode-dependent dissipation and allowable component temperatures.
Contact conductance, flatness, preload and interface material.
Conductive heat spreading and controlled transport.
Area, orientation, optical properties and view to space.
Protection against external loads and cold-case excursions.
Design warning: Applying MLI over an intended heat-rejection surface can trap internally generated heat. Blanket exclusion zones, radiator boundaries and harness or structural heat leaks must be resolved in the same model.
Flight-hardware detail engineering
Multi-Layer Insulation (MLI) Engineering for Satellites
Satellite MLI insulation is a lightweight blanket system of low-emittance reflective layers separated by low-conductance spacers and protected by mission-appropriate outer and inner covers. Layer architecture is selected together with mass, geometry, venting, contamination, optical and integration requirements.
More MLI layers do not automatically create better performance. Excessive layer density, local compression, metallic contact, poorly controlled seams, penetrations and fasteners can create thermal short circuits that materially reduce effective performance.
ERATHERM translates the thermal model into blanket zones, layer schedules, manufacturing patterns, closures, exclusion zones, attachment details and an as-built configuration that can be inspected and correlated with test results.
- Outer-cover and optical-property selection
- Reflective layer, spacer, layer count and density definition
- Blanket mass, thickness, venting and contamination review
- Seams, overlaps, edges, apertures and penetrations
- Attachment, stand-off, bonding and grounding coordination
Blanket architecture and integration
MLI Blanket Details That Determine As-Built Performance
The model and the manufactured blanket must describe the same thermal configuration, including real interfaces and workmanship-sensitive areas.
Cover, Reflectors & Spacers
Mission-compatible films, deposited surfaces, spacer media and protective covers selected for optical, thermal, mechanical and contamination requirements.
Layer Count & Density
Layer arrangement balanced against effective emittance, blanket thickness, mass budget, manufacturability and compression sensitivity.
Perforation & Venting
Controlled gas release during ascent and pump-down without uncontrolled billowing, trapped volumes or damage to blanket geometry.
Seams, Overlaps & Edges
Overlap direction, edge finish and local closures designed to limit radiative openings and conductive bridges.
Cut-Outs & Penetrations
Purpose-designed details around sensors, radiators, thrusters, antennas, connectors, harnesses and mechanical interfaces.
Attachments & Stand-Offs
Fastener layout, local reinforcement, isolation and access coordinated without excessive blanket compression or contact.
Bonding & Grounding
Electrical continuity and grounding provisions coordinated with spacecraft EMC, charging and customer requirements.
Cleanliness & Traceability
Approved materials, handling, identification, workmanship inspection and as-built configuration control for verification.
Passive and active thermal control
MLI Within an Integrated Satellite Thermal Control System
The correct mix of passive and active devices depends on thermal limits, gradients, stability, available power, radiator area and mission operating modes.
MLI, Coatings & Radiators
External heat absorption, internal radiative coupling and heat rejection managed through zoning, surface properties and view to space.
Interfaces, Spreaders & Straps
Thermal interface materials, structural paths, doublers and flexible straps distribute or isolate heat where required.
Heat Pipes & Loop Heat Pipes
Passive transport options considered where long heat paths, local heat density or radiator placement require enhanced transfer.
Heaters & Thermostats
Survival and operational heaters sized against cold cases, control thresholds, duty cycle, redundancy and available power.
Temperature Sensors
Sensor type and location planned around control, flight monitoring and meaningful correlation of analysis and test results.
Thermal Isolators
Low-conductance interfaces reduce parasitic heat flow while being checked against structural load, alignment and integration constraints.
Component-level temperature control
Space Electronics Thermal Stabilization
Thermal stabilization means maintaining equipment within its permitted temperature range, gradient and stability band throughout operation, standby, eclipse and survival modes. Depending on the case, the solution may need to remove heat, retain heat or add controlled heater power.
Equipment dissipation is mapped by mission mode and duty cycle. Mounting interfaces, nearby heat sources, harness conduction, allowable temperatures, radiator access and heater-power limits are then assessed together rather than as isolated component values.
Avionics & On-Board ComputersTemperature range, interface conductance and peak-mode dissipation
Power Electronics & RF UnitsHigh local heat flux, duty cycle and conductive spreading
Payloads & Electro-Optical SensorsGradients, short-term stability and line-of-sight constraints
Batteries & ActuatorsOperational/survival bands, internal heating and cold-case control
Design output: Each critical unit receives a traceable temperature prediction and margin assessment for the required hot, cold, operational and survival cases.
Orbit-to-component modelling
Spacecraft Thermal Analysis from GMM to Correlated TMM
The thermal model converts mission geometry, surface properties, conductive interfaces and equipment power profiles into component-level temperature predictions.
Model boundary: The purpose is not a single average spacecraft temperature. The model must predict temperatures and gradients at the components and interfaces that drive mission performance and qualification.
Construction and integration-ready outputs
Spacecraft Thermal Engineering Deliverables
The package can be tailored from an independent design review to a coordinated thermal-control and MLI engineering scope.
Requirements MatrixMission, component and interface thermal limits
Thermal Design BasisInputs, cases, assumptions and margins
GMM & TMMGeometry, nodes, couplings and boundary conditions
Thermal Analysis ReportHot/cold predictions and component margins
Thermal-Control ArchitecturePassive and active device coordination
MLI Design SpecificationMaterials, layers, workmanship and acceptance
Blanket Layouts & PatternsZones, cuts, seams, apertures and attachments
Thermal Interface DrawingsRadiators, straps, isolators and equipment interfaces
Heater Sizing InputsPower, set points, duty and control logic basis
Thermal-Control BOMMaterials, blankets, devices and traceability
Integration & Inspection PlanSequence, hold points and configuration checks
Model Correlation ReportTest comparison, updates and as-built model
MLI manufacturing definition
Blanket Layouts, Patterns and Configuration Control
MLI engineering becomes usable when the analysis is converted into manufacturable blanket geometry and controlled interfaces. Deliverables can include zoning plans, CAD layouts, cutting patterns, material schedules, seam and overlap details, attachment points, aperture details, radiator and sensor exclusion zones, harness interfaces and installation sequences.
Blanket identification, revision status and as-built configuration are retained so the installed hardware can be compared with the model and test article. Removal and reinstallation instructions can be defined for access-sensitive areas.
Configuration principle: Unrecorded changes to blanket geometry, compression, apertures or radiator boundaries can invalidate local model assumptions. Integration changes therefore require thermal review.
One coordinated engineering sequence
From Mission Inputs to Thermal Verification
The thermal-control architecture is matured with the spacecraft design and retained as a traceable chain from requirement to verified configuration.
Verification beyond analysis
Thermal Verification, TVAC Testing and Model Correlation
Verification confirms both the hardware configuration and the model's ability to predict temperatures under representative boundary conditions.
Materials & Workmanship
Material approval, outgassing documentation, cleanliness, layer count, seams, overlaps, attachments and configuration inspection.
TVAC & Thermal Balance
Test cases, chamber boundaries, sensor locations and power modes planned to exercise critical thermal-control functions.
Model Correlation
Predicted and measured temperatures compared, uncertain parameters adjusted within justified ranges and the model updated.
Verification distinction: Thermal cycling demonstrates survival and functional performance across specified extremes. Thermal-balance testing is structured to support correlation of the analytical thermal model. Project requirements define the final test philosophy.
Project-governed compliance framework
ECSS, Customer and Mission Requirements
Applicable standards are selected through the contract, mission assurance plan and customer requirements. They are used as project reference frameworks, not presented as a claim that every standard applies to every spacecraft or that a specific hardware configuration is automatically flight-qualified.
The governing sequence is the contract and mission requirements, approved spacecraft data and interfaces, approved materials and processes, analysis and verification plan, followed by applicable ECSS, customer or agency documents.
ECSS-E-ST-31Spacecraft thermal-control engineering framework covering definition, analysis, design, verification and operation.
ECSS-E-HB-31-01 — Part 7AThermal design handbook guidance for insulation and MLI engineering.
ECSS-E-HB-31-01 — Part 6AReference guidance for thermal-control surfaces and optical properties.
ECSS-E-HB-31-03Thermal analysis, verification and model-correlation guidance.
ECSS-Q-ST-70-01 & ECSS-Q-ST-70-02Cleanliness/contamination control and thermal-vacuum outgassing screening.
Mission-Specific RequirementsApplicable customer, agency, launch-provider, quality and product-assurance requirements.
Specialised thermal engineering
From Cryogenic Test Infrastructure to Spacecraft Thermal Engineering
ERATHERM combines more than 20 years of thermal engineering with vacuum, MLI, cryogenic and satellite test-infrastructure experience. Capabilities include thermal analysis, detail engineering, material and interface definition, integration planning, inspection and verification support.
Experience boundary: ERATHERM's space-infrastructure and specialised thermal-system experience supports mission-specific satellite engineering and qualification programmes. This page does not claim flight-proven blankets, flight-qualified hardware or in-orbit heritage unless such status is established for a defined project and configuration.
Space Test SystemsThermal-vacuum and satellite test-infrastructure experience
Cryogenic to High HeatBroad thermal-envelope engineering capability
MLI & VacuumInsulation architecture and interface know-how
Integrated DeliveryAnalysis · Detail design · Integration · Verification
Connected space and vacuum capabilities
Continue with the Right Technical Scope
Frequently asked questions
Satellite MLI and Spacecraft Thermal Control FAQ
What is satellite MLI insulation?
Satellite MLI is an engineered blanket of low-emittance reflective layers separated by low-conductance spacers and protected by mission-appropriate covers. In vacuum, it limits radiative heat exchange across selected spacecraft surfaces. Its real performance depends on layer architecture, compression, seams, cut-outs, attachments, venting and integration quality.
Is MLI the complete spacecraft thermal control system?
No. MLI is one passive thermal-control element. A complete system may also use radiators, coatings, thermal interface materials, spreaders, straps, heat pipes, heaters, thermostats, sensors and thermal isolators. These elements must be coordinated with equipment dissipation and mission cases.
Does adding more MLI layers always improve insulation?
No. Additional layers can help only within a controlled architecture. Excessive layer density, local compression, metallic contact, poorly designed seams and penetrations can create thermal short circuits and reduce effective performance. Layer count is balanced with mass, geometry, venting and manufacturing constraints.
How is space electronics thermal stabilization achieved?
Equipment dissipation, duty cycle, mounting interfaces, allowable temperatures, gradients, nearby heat sources, radiator access and heater power are assessed for each mission mode. The solution may conduct heat to a radiator, thermally isolate the unit, retain heat with MLI or add controlled heater power during cold cases.
What are GMM and TMM in spacecraft thermal analysis?
The Geometrical Mathematical Model (GMM) represents geometry, surface zoning, orientation, shadowing and radiative view factors. The Thermal Mathematical Model (TMM) represents thermal nodes, capacities, conductive and radiative couplings, boundary conditions and equipment dissipation used to predict temperatures.
What MLI engineering documents can ERATHERM prepare?
The scope can include a thermal design basis, MLI construction specification, material and layer schedule, blanket zoning, CAD layouts, manufacturing patterns, seam and overlap details, attachments, apertures, radiator exclusion zones, bonding and grounding details, BOM, integration instructions and as-built configuration records.
Why are MLI venting and perforation details important?
Trapped gas must escape in a controlled manner during ascent and vacuum-chamber pump-down. Inadequate venting can cause billowing, displacement or damage, while vent geometry must also remain compatible with thermal performance, contamination control and mission requirements.
What is the difference between thermal cycling and thermal-balance testing?
Thermal cycling demonstrates survival and functional performance across specified temperature conditions. Thermal-balance testing uses controlled boundary conditions and operating modes to compare measured temperatures with predictions and support correlation of the spacecraft thermal model. The project verification plan defines the required tests.
Can ERATHERM claim flight heritage for satellite MLI?
This page describes ERATHERM's engineering capability based on thermal, vacuum, cryogenic and space test-infrastructure experience. Flight heritage or flight-qualified status should only be claimed for a specifically documented mission, product and configuration; it is not implied by this general service page.
Define the mission thermal architecture
Develop Your Satellite Thermal Control and MLI Scope with ERATHERM
Share the orbit and mission modes, spacecraft geometry, component temperature limits, dissipation profiles, interfaces and verification philosophy. Our engineers can define the analysis basis, thermal-control architecture, MLI details and TVAC-supported verification plan.
Final thermal-control architecture, MLI materials, blanket details, margins, verification methods and standards are mission- and project-specific and must be confirmed against the contract, customer requirements, approved spacecraft data, manufacturer information and applicable product-assurance rules. References on this page are a technical framework, not a claim that every standard applies to every project. This page does not claim flight-proven hardware, flight qualification or in-orbit heritage unless documented for a defined mission and configuration.