Analysis of DRIRU bearings and lubricant from solar max repair mission

The Solar Maximum Repair Mission (SMRM) by the shuttle astronauts in April 1984, returned to Earth the Delta Redundant Inertial Reference Unit 2 (DRIRU 2) from the Solar Maximum satellite. The DRIRU 2 included three gyroscopes. The gyroscope, S/N 094, in position 2 was disassembled by Teledyne Systems personnel of Northridge, California, and the bearings were returned to Goddard Space Flight Center for examination. The Solar Max Satellite was in orbit for 4 years with the bearings running continuously at 6000 rpm. The ball bearings, had sufficient remaining lubrication and had runs successfully for over the last 4 years. As a result of these findings, the bearings should have lasted their predicted life of 5 years with no problems.