L3-CRY-COOL-STIR
CRITICAL
PRESERVATION
Level 3 · hardware
Stirling Cryocooler Unit
Sunpower CryoTel-class Free-Piston Stirling Cryocooler
Free-piston Stirling cryocooler maintaining -196C sample storage temperature
Purpose
Free-piston Stirling cryocooler maintaining -196C sample storage temperature
Context
Child of L2-CRY-COOL
Principles
- ▸Free-piston Stirling cycle uses gas spring (no mechanical linkage) for extreme reliability
- ▸Flexure bearings eliminate contact wear enabling >100,000 hour MTBF
- ▸Regenerator efficiency >95% critical for achieving cryogenic temperatures
- ▸Opposed-piston configuration cancels vibration that could damage samples
Typical implementations
- ▸Sunpower CryoTel GT/CT/MT Stirling cryocoolers (>60,000 hr demonstrated life)
- ▸Thales Cryogenics LSF Stirling coolers (space heritage on JWST precooler)
- ▸Lockheed Martin micro-pulse-tube precooler for JWST MIRI
- ▸RICOR K508 tactical Stirling cooler (miniature, high reliability)
Lunar considerations
- ▸No atmosphere for heat rejection - condenser side must couple to radiator via conduction
- ▸Triple-redundant coolers (2 active + 1 standby) prevent single-point failure
- ▸Vibration from Stirling mechanism must be isolated from sensitive samples
- ▸100-year mission requires multiple cooler replacements via robotic maintenance
Specifications
Functional
| primary function | Free-piston Stirling cryocooler maintaining -196C sample storage temperature |
Physical
| materials | Maraging steel flexures, Helium working gas, Stainless steel pressure vessel, Copper cold finger |
Interfaces
Provides
- Cooling power maintaining -196C storage temperature
Requires
- Electrical power for cryocooler compressor (~100-300W)
- Heat rejection path for cryocooler warm end
Cite this entry
Lunar Ark Codex. "Stirling Cryocooler Unit" (L3-CRY-COOL-STIR). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-CRY-COOL-STIR
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.