The Smoital System — A method of timekeeping on Mars based on UTC

A paper outlining a simple timekeeping system suitable for initial civil use on Mars. he system specifies nearly all Martian calendar days as exactly 24 hours and 40 minutes in length (Earth units), closely matching the true Martian solar day, with the exception of 6 or 7 intercalary days per Martian year, which are defined as only 24 hours long.