ESA GNC Conference Papers Repository
Reaction Wheel Unit Design Update and Re-Qualification
In August 2006, Bradford Engineering (BE) acquired the Reaction Wheel Business from Stork Product Engineering (SPE). The true origin of this technology finds itself in Astrium Ltd. (Mechanisms Product Group, Stevenage), which in turn had transferred the Reaction Wheel Unit (RWU) technology successfully to SPE in June 2001. Bradford Engineering has transferred and absorbed all necessary information and hardware (test hardware, tooling, documents, know-how/knowledge and skills) to enable to continue this activity with the same quality and confidence as Astrium Ltd. In order to demonstrate the successful transfer and to prove that BE is a qualified supplier, a RWU design update and re-qualification program is currently in progress under GSTP4 funding. In the frame of this program firstly an existing RWA has been refurbished by BE personnel, where after the design update and re-qualification plan has been initiated to achieve a complete rebuild of a W18 or W45 RWA and a single channel Wheel Drive Electronics (WDE) on Qualification Model (QM) level. The RWU design update and re-qualification will be performed on the W18 or W45 type of Reaction Wheel Assembly (RWA) with the digital WDE (MIL-1553B). This technology was delivered e.g. for the Rosetta, XMM and Integral missions. The W18 and W45 type RWA offer superior performances in terms of momentum storage, torque and wheel speed measurement and have excellent zero-crossing and micro vibration characteristics. The RWA implements the latest technology in terms of bearing/lubrication system and heater function. The Rosetta, XMM and Integral projects are well documented and well explored in terms of endurance tests (life tests). Through the RWU update and re-qualification approach, maximum leverage of heritage is obtained and overall program risks are minimized.