De-risk assessment: Improvement of Reliability and Lifetime for Rotary Type Stirling Coolers
Programme
GSTP
Programme Reference
G617-241TAgs
Prime Contractor
Le-tehnika do.o.
Start Date
End Date
Status
Closed
Country
Slovenia
Objectives
•Improve the lifetime and reliability of an existing rotary cooler to make it adequate for space missions.
Description
Background and justification:
•Rotary-type Stirling cryocoolers are widely used in defence applications and are cheaper to build than standard Space industry coolers, which are usually linear-type Stirling coolers. However, rotary coolers are not currently used in Space because they have a lower lifetime and reliability. Increasing their lifetime is the key challenge to allow their use in spacecraft.
•This activity is based on an existing cooler design which is already produced in high numbers in order to help keep costs significantly lower than space-only cryocoolers, which are produced in extremely small numbers.
Achievements and status:
•A root-cause analysis (RCA) was performed to identify the cause for failure of coolers from 94 customer claims.
•Tests were defined and run based on the RCA analysis to introduce solutions to the identified failure modes. This campaign included tests to improve processes (e.g., bearing preload measurements, cleanliness was improved, new assembly tools were built) and tests to introduce new components (e.g., tribological and lifetime testing of coatings and bearings).
•A lifetime-improved cooler was designed based on these test results, introducing 16 design and process changes to improve lifetime and reliability (change of coatings, bearings, addition of balancing masses, improvement of axial preload, removing of air traps, etc.).
•Six breadboards of the improved coolers were built and tested.
Benefits:
•Achieving sufficient lifetime and reliability for rotary Stirling coolers would enable missions requiring cryocoolers (in particular with infrared detection for Earth observation or science) to be realized at a cheaper cost, especially in New Space where a lower cost is desirable, and a lower lifetime or higher risk can be accepted. Another promising application are scientific missions with multiple instruments, where cheap small-scale cooling is often needed on one of the instruments.
Application Domain
Generic Technologies
Technology Domain
26 - Others
Competence Domain
2-Structures, Mechanisms, Materials, Thermal
Initial TRL
TRL N/A
Target TRL
TRL N/A
Achieved TRL
TRL N/A
Public Document
Executive Summary