The Barden Corporation (UK) Ltd, a Schaeffler subsidiary based in Plymouth (see Machinery Market 15 November, page 16), is supplying high-precision and high-reliability bearings to support onboard sub-systems, such as reaction wheels for the burgeoning satellite industry.

In the past, building a civil telecommunications satellite and launching it into space required a multi-million-pound investment; now, both the size of satellites and the cost of launching them have fallen, with an increasing number being launched from Europe, Turkey, India, China and elsewhere.

A reaction wheel is a type of flywheel used primarily by spacecraft and satellites for attitude control; a satellite typically has three reaction wheels (for the X, Y and Z axes).

The failure of one or more of them can cause a mission to fail, so the reliability of the wheel bearings is critical. They must reliably spin for up to 15 years in a vacuum environment, with only a small amount of lubricating oil on the bearing surfaces.

At the same time, they must minimise any vibration. They must also withstand the vibration and loads at launch, plus the temperature variations while in orbit.

At Barden UK (www.bardenbearings.co.uk), reaction-wheel bearings are typically custom-engineered angular-contact ball bearings that are manufactured with a high level of surface finish. They are assembled in clean-room conditions, using special handling techniques.

Every part of the rolling contact surface is inspected, and any slight defect is captured, commented on and documented. The bearings are typically shipped in pairs as a kit, ready for further examination and screening by the customer before assembly/fitting.