Division of Information Technology, Engineering and the Environment
School of Advanced Manufacturing and Mechanical Engineering
School of Advanced Manufacturing and Mechanical Engineering
Thesis Abstract
Spacecraft incorporates a wide variety of machine elements which must operate with total reliability in space environment. Each subsystem of a spacecraft is a combination of both electronic and mechanical components. These subsystems are designed to work effectively and efficiently for the entire mission period. In recent years the electronic components have been significantly advanced compared to the advances in tribology. However, the demand for space systems seems to grow faster than the tribotechnology, which becomes the limiting factor in determining mission length. Most spacecrafts use momentum wheels, reaction wheels and control moment gyros for the attitude control. These elements use high precision angular contact ball bearings and run continuously at speeds of several thousand rpm (typically, 4000 to 6000 rpm). Also these must run for many years with stable performance and high reliability. Earlier spacecrafts were designed to operate up to 10 years and presently the attention is focused on the development of satellites which can operate for more than 20 years. To achieve this augmented operating life, it is quite obvious that the advancement of tribology technology is essential. The current research is aimed to address this critical issue. The objective of this research project is to develop a lubricant supply system which can supply lubricant continuously for a minimum of 20 years at the possible lowest flow rate. The proposed system will be compact and fit inside the bearing unit. The targeted flow rate is less than 10 microgram per hour which is less than the reported flow rate achieved. The expected outcome, which is a new lubrication system, will support a mission life more than 20 years.
