Key vacuum technology issues to be solved in evacuated tube transportation

Evacuated tube transportation （ETT） will be one of the ultra-large-scale vacuum application areas. This paper lists some key vacuum technology issues in ETT： （1） how to construct ultra-large-scale vacuum chamber with lower cost and high reliability, （2） how to evacuate gas out of the ETT tube in short time, （3） how to release heat or reduce temperature in the vacuum tube, （4） how to avoid vacuum discharge, （5） how to make vehicles with airproof shells and life support system, and （6） how to detect leaks and find leak positions efficiently. At the same time, some solutions are proposed.