The proprietary Hemispherical Resonator Gyro (HRG) operates in a vacuum, so it's at home in the vacuum of space. We evacuate the HRG at our production facility to perform ground testing, and once launched into space, it has no wear out mechanism for the life of the spacecraft. Its life in space is unmatched.
HRG's high reliability comes also from its simple construction of three pieces of machined quartz. This quartz material also makes it naturally radiation hard in any space environment. HRG is a small gyro, weighing less than 0.5 lb per sensor. This small size and weight enables the IRU form factor to be small, facilitating its design into a spacecraft.