Thermo-Modulating Heat Pipes (TMHPs)
ACT (Advanced Cooling Technologies)
A dual-mode spacecraft thermal device combining VCHP and thermal diode functions in a single gas-charged aluminum-ammonia design, eliminating the separate NCG reservoir for reduced mass and cost.
Technical specifications
- Working Fluid / Envelope
- Aluminum-ammonia
- NCG Reservoir
- Integrated (no separate reservoir)
- Demonstrated Load (VCHP Mode)
- ~36 W
- Operating Modes
- VCHP mode (forward); Diode mode (reverse blocking)
- Control Method
- Passive (Non-Condensable Gas)
About
The Thermo-Modulating Heat Pipe (TMHP) merges the functions of a Variable Conductance Heat Pipe (VCHP) and a thermal diode into a single simplified device. Unlike traditional VCHPs that require a separate external NCG reservoir, the TMHP stores non-condensable gas within the condenser section, reducing component count, mass, and overall complexity.
The TMHP operates in two distinct modes. In VCHP mode, the NCG incrementally blocks condenser area at lower sink temperatures, regulating heat transfer. In diode mode, when the radiator temperature exceeds the payload temperature, the NCG fully blocks the evaporator to prevent backflow of heat — acting as a one-way thermal valve. Experimental demonstrations have validated performance at approximately 36 W load in VCHP mode.
Documentation
No public datasheet yet — request the datasheet / ICD from the supplier.
