Chain and sprocket drives of one form or another have been driving machines and
conveying materials for over a thousand years. The chain manufacturing industry has developed numerous types and sizes of drive chains. Although it is a mature form of power transmission, there are still many industrial applications for which drive chain is suited. It is economical, resistant to shock loads, easy to install, has the ability to transmit high torque, operates in hostile environments, and is efficient. Chain and sprocket drives are highly engineered and manufactured within close tolerances.
It was recently announced that the planet Mars has at least one thing in common with planet Earth: all good things come to an end. In this case, the good thing is the recently announced and documented (Feb. 12) demise of the Mars rover Opportunity.