Before revision: Current status In 2020, a free-piston Stirling power convertor reached 14 years of maintenance-free and degradation-free cumulative operation in the Stirling Research Laboratory at NASA Glenn.
After revision: Current status In 2020, a free-piston Stirling power convertor reached 15 years of maintenance-free and degradation-free cumulative operation in the Stirling Research Laboratory at NASA Glenn.