Surrey Satellite Technology (SSTL) is using a dynamometer from Kistler to measure the forces produced by positioning wheels on a satellite.
Launching a satellite places huge vibrational loads on the payload, making the need to over engineer and thoroughly test every component essential to ensure that these loads do not compromise the satellite's performance.
Typically, the positioning wheels - which maintain the satellite in alignment with a ground-station antenna when downloading data, or a specific area when imaging - use precision ball-race bearings that can become pitted in the launch phase, resulting in electro-mechanical noise during in-space operation.
This noise can interfere with the operation of the delicate electronics used for imaging and navigation systems on the satellite.
To simulate the operation of the positioning wheels, SSTL uses a test rig based on a three-component dynamometer, which measures the forces produced by the positioning wheels.
It is this force that, in space, maintains the satellite antenna in line with an earth station or a particular constellation depending on the mission objective.
When the positioning wheels run at around 5,000rpm to make a large change in the satellite position, noise is not a problem, but when making small, repeated adjustments, noise can cause camera shaking, resulting in blurred imaging or loss of lock in the star-camera positioning system.
