Sherborne Sensors' inclinometers support RUAG Space
28/03/2012 Sherborne Sensors Limited
Custom servo inclinometers deliver precision performance throughout testing of new Thruster Orientation Mechanism for satellite platformsLondon, UK, 27 March 2012 - Sherborne Sensors, a global leader in the design, development and manufacture of sensors for military, aerospace and industrial applications, has helped RUAG Space, Europe's largest independent supplier of space technology, to complete life test qualification of its innovative satellite Thruster Orientation Mechanism (TOM). Sherborne Sensors supplied a special variant of its LSI Servo Inclinometer to deliver precision performance throughout three months of rigorous testing under extreme temperature and thermal vacuum conditions.
Pointing mechanisms and electrical propulsion (EP) thrusters are used by commercial satellites for moving from launch orbit into their real orbit and to perform micro-positioning manoeuvres. RUAG's new TOM simplifies the overall design of a satellite by having two TOMs instead of the eight stationary thrusters units employed in conventional designs. Sherborne Sensors' LSI Servo Inclinometer was mounted on the TOM qualification model in order to perform three key tests - mechanical pointing accuracy, potentiometer verification and motor margin - in a large vacuum chamber, where an extremely low pressure of 10-7 mbar (known as a 'hard vacuum') is achieved to simulate the in-orbit environment.
"Finding measurement devices capable of operating at this very low pressure is not easy to do," says Andrew Skulicz, AIT Engineer at RUAG Space. "The most important aspect was that they were able to operate between -40°Fand +104°F under hard vacuum conditions. Sherborne Sensors was the only company that could provide us with inclinometers that covered the range that we wanted, together with accuracy of better than +/-0.05°. The inclinometers on the TOM not only successfully operated throughout a sequence of thermal vacuum cycles, but also sustained that operation for nearly three months while the mechanism was undergoing its life test."
Sherborne Sensors was careful to ensure the inclinometers did not contain any compounds that would suffer the outgassing of organic compounds such as adhesives and rubber, while providing the case of the inclinometer with a vent to counter the effect of differential pressure between the sealed case of the inclinometer and the vacuum conditions it was used in. With the test results demonstrating and verifying the TOM's performance against everything it can reasonably expect to experience from manufacture through mission to end-of-life, RUAG's TOM programme represents the cutting edge of the European scientific community and is approved by the European Space Agency (ESA).
"Our customisations ensured that there was no danger of any minor leaks destroying the high vacuum conditions over time, as well as relieving any mechanical stresses that could occur during de-pressurisation," adds Mike Baker, managing director at Sherborne Sensors. "The LSI was also characterised for performance over the applications operable temperature range to give a high degree of accuracy. We also provided RUAG with a 'look-up' chart listing the individual temperature errors over the complete range of environmental temperatures expected to be met in the application. This enabled RUAG to correct in real time for the effects of temperature and deliver more accurate results."
For further information go to www.sherbornesensors.com
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