Press Release

NSK Develops High-Performance Wheel Bearing for Satellite Attitude Control

Already Being Used in Space First of Its Kind Using Homegrown Japanese Technology

Tokyo, Japan, February 17, 2010 - NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Norio Otsuka) today announced that it has developed a high-performance wheel bearing for satellite attitude control, the first such device to be developed using homegrown Japanese technology. The new wheel bearing is already in use on the greenhouse gases observing satellite (GOSAT) “IBUKI”*. The IBUKI satellite was launched by the Japan Aerospace Exploration Agency (JAXA) in January 2009, and since that time has been beaming a steady stream of observational data back from space.

High-Performance Wheel Bearing for Satellite Attitude Control

The attitude control wheel on a satellite uses a motor to accelerate and decelerate an internal rotating mass in the form of a flywheel. The reaction torque that this generates is used to provide attitude control for the satellite. Bearings are one of the core components affecting the performance of the reaction wheel. The bearings in an attitude control wheel must satisfy demanding requirements, by continuing to reliably spin for a long period of 10–15 years while orbiting in space, using only a small amount of lubricating oils on the bearing surfaces in a vacuum environment. At the same time, the bearings must minimize any vibration, so as not to negatively affect the observational performance of the satellite. The bearings must also withstand the vibration and impact from launch, and endure temperature variations while in orbit.

The bearing developed by NSK offers the high degree of reliability needed for control attitude wheels, delivering low vibration, high-speed rotation, and high output.

Note: The realization of this technology as a product was made possible in cooperation with JAXA and Mitsubishi Precision Co., Ltd.
*1: The greenhouse gases observing satellite IBUKI is a JAXA project whose purpose is to measure the distribution in the concentration of greenhouse gases that induce global warming, in order to contribute to the effort to reduce carbon dioxide emissions as stipulated under the Kyoto Protocol. By extensively monitoring environmental changes on a global scale, the satellite is providing data useful in securing the future of humankind. (Based on information from JAXA website.)

Product features

Technology for improved reliability
Employs lubrication oils formulated to prevent evaporation while delivering superior lubricating performance, and a retainer capable of providing a reliable supply of lubrication oil in minute quantities.
Low vibration technology
Utilizes races made from high purity, carbide-refined stainless steel to achieve low vibration, and a proprietary cleaning technology that leaves the races with a high purity surface. Employs high-precision steel balls featuring a special surface treatment for superior wear resistance

NSK will continue to develop state-of-the-art technology for aerospace development, with the aim of helping to build safe, smoothly operating societies.