Abstract
The growing demand for EO applications that work around the clock 24hr/7days a week, such as in border surveillance
systems, emphasizes the need for a highly reliable cryocooler having increased operational availability and decreased
integrated system Life Cycle (ILS) cost. In order to meet this need RICOR has developed a new rotary Stirling
cryocooler, model K508N, intended to double the K508's operating MTTF achieving 20,000 operating MTTF hours.
The K508N employs RICOR's latest mechanical design technologies such as optimized bearings and greases, bearings
preloading, advanced seals, laser welded cold finger and robust design structure with increased natural frequency
compared to the K508 model.
The cooler enhanced MTTF was demonstrated by a Validation and Verification (V&V) plan comprising analytical
means and a comparative accelerated life test between the standard K508 and the K508N models. Particularly, point
estimate and confidence interval for the MTTF improvement factor where calculated periodically during and after the
test. The (V&V) effort revealed that the K508N meets its MTTF design goal. The paper will focus on the technical and
engineering aspects of the new design. In addition it will discuss the market needs and expectations, investigate the
reliability data of the present reference K508 model; and report the accelerate life test data and the statistical analysis
methodology as well as its underlying assumptions and results.
