Isabellenhütte has introduced the HFF flexible heater, a Kapton®-laminated etched-foil heater qualified to ESCC Detail Specification No. 4009/006.
The announcement adds a space-qualified thermal-control component for spacecraft and extraterrestrial vehicles, with configurable geometry, resistance, lead exit and optional pressure-sensitive adhesive.
Key features and benefits
- HFF is a flexible heater built around an etched MANGANIN® foil heating structure laminated between polyimide films.
- The published operating-temperature range is −55 °C to +150 °C.
- Resistance values span 1 Ω to 2,000 Ω, with 5% or 10% tolerance options.
- Power density is specified up to 2.0 W/cm²; the standard rated power density is 0.38 W/cm².
- Wire leads comply with ESCC 3901/012.
- The construction is qualified to ESCC Detail Specification No. 4009/006.
- Pressure-sensitive adhesive is optional, allowing the mounting method to be specified as part of the heater configuration.
- The HFF ordering code accommodates heater dimensions, resistance, tolerance, lead-exit geometry, adhesive option, wire gauge and wire length.
The key change is the availability of an ESCC-qualified flexible heater from Isabellenhütte’s resistor portfolio. The manufacturer positions it as an additional European source for thermal management in spacecraft and extraterrestrial vehicles.
Technical highlights
| Parameter | HFF published value | Selection relevance |
|---|---|---|
| Heater technology | Etched MANGANIN® foil | Resistive heating element |
| Insulation structure | Kapton® laminate | Flexible electrical insulation |
| Applicable temperature | −55 °C to +150 °C | Thermal operating envelope |
| Resistance range | 1 Ω to 2,000 Ω | Sets supply voltage and power |
| Resistance tolerance | 5% or 10% | Power-budget tolerance |
| Power density | Up to 2.0 W/cm² | Thermal-load sizing |
| Standard rated density | 0.38 W/cm² | Reference operating condition |
| Qualification | ESCC 4009/006 | Space-component qualification |
| Lead-wire specification | ESCC 3901/012 | Harness-interface requirement |
The HFF datasheet is labelled preliminary version, Issue 16-September-2026. It also includes a power-derating curve referenced to terminal temperature, so maximum usable input power must be set from the final thermal interface and terminal-temperature condition rather than from the headline 2.0 W/cm² figure alone.
Published mechanical limits are configuration-dependent. The ESCC detail specification defines a heater outline with dimensions of 5 mm to 265 mm for dimension A and 40 mm to 385 mm for dimension B; the specific heater construction, dimensions and layout are defined by the manufacturer’s heater design drawing. The ordering code identifies dimensions using AAA and BBB fields, with 50 mm × 200 mm given as an example.
Typical applications
The HFF documentation supports thermal management in spacecraft and extraterrestrial vehicles. Its −55 °C to +150 °C temperature range, ESCC qualification and configurable foil-heater geometry are directly relevant where a controlled heat input must be integrated onto or close to an item requiring temperature maintenance.
- Battery thermal control: The flexible heater format can conform to a defined battery-module interface. Resistance tolerance, supply-voltage variation and the final thermal path into the cell or enclosure must be included in the heater power budget.
- Propellant lines and valves: The 1 Ω to 2,000 Ω resistance range permits resistance to be selected around the available spacecraft power bus and switching architecture. Harness voltage drop and local heat sinking require verification at the final installation.
- Optical and electronic equipment: The −55 °C to +150 °C range supports use within the heater’s published temperature envelope, but local temperature sensing and control-loop behaviour remain system responsibilities.
- Spacecraft structures and rover subsystems: The configurable heater dimensions, lead exit and optional adhesive support mechanically tailored installations where a rigid heater would be difficult to integrate.
The announcement also names satellites, launch vehicles and rover systems. The available HFF documents substantiate the product’s general spacecraft and extraterrestrial-vehicle positioning, but do not publish application-specific thermal models, power budgets, mounting instructions or endurance data for individual platforms.
Application fit
| Circuit position | Published support | Design check |
|---|---|---|
| Local thermal-control heater | 1 Ω–2,000 Ω resistance | Bus voltage and power tolerance |
| Bonded equipment heater | Optional PSA | Bondline and vacuum compatibility |
| Harnessed heater assembly | ESCC 3901/012 leads | Wire gauge and voltage drop |
| Space thermal subsystem | ESCC 4009/006 qualification | Mission DCL and design drawing |
Flexible heaters are resistive components rather than passive heat sources with a fixed thermal output. Electrical input power becomes useful heat only through the complete installation: heater area, mounting interface, substrate material, radiative environment, heat losses, harness resistance, control algorithm and sensor placement all affect the resulting temperature.
The datasheet specifies stability of less than ±4% after 2,000 hours at 0.38 W/cm² in free air. That test condition should not be translated directly into mission lifetime, on-orbit temperature uniformity or installed power capability, because the final system environment differs materially from free-air testing.
Design-in notes for engineers
- Select heater resistance from the actual minimum and maximum supply voltage, not only nominal bus voltage. The 5% or 10% resistance tolerance changes the delivered power at a fixed voltage.
- Use the datasheet derating curve with terminal temperature. A heater bonded to a conductive structure, mounted on a thermally insulating surface or operating in vacuum can have materially different thermal behaviour.
- Treat the 2.0 W/cm² value as a maximum published power-density limit, not a default operating point. The datasheet identifies 0.38 W/cm² as the standard rated power density.
- Obtain the heater design drawing for the exact outline, heated area, margin, lead exit, wire gauge and wire length before releasing the mechanical layout or harness drawing.
- Confirm whether the optional pressure-sensitive adhesive is suitable for the final substrate, preparation process, temperature profile and applicable mission materials requirements. No public HFF mounting or outgassing guideline was identified.
- Assess fault conditions, including controller failure, sensor open or short circuit, supply overvoltage and local thermal isolation. A system-level independent temperature limit may be necessary.
- Qualification to ESCC 4009/006 applies to the component specification; it does not replace validation of the final heater installation, thermal control loop and mission duty cycle.
- The public HFF documentation does not provide SPICE models, impedance curves, S-parameters, a separate reliability report, product-change notice, lifecycle notice, land pattern or soldering guideline. These gaps are expected for a wired, custom-outline heater, but final configuration control should be obtained from the manufacturer.
Further reading
- Flexible Heaters Technological Challenges and Roadmap
- EEE Components Qualification Challenges and Approaches for Cryogenic Temperature
- Improving SMPS Performance with Thermal Interface Material
Source
This information is based on Isabellenhütte’s September 2026 press release and official HFF product documentation. Engineers should consult the current manufacturer datasheet, applicable ESCC documentation and the configuration-specific heater design drawing before final qualification and design release.
