Islamic calendar lunar months begin precisely at the time of the monthly "conjunction", when the Moon is located most directly between the Earth and the Sun. The month is defined as the average duration of a revolution of the Moon around the Earth (29.53 days). By convention, months of 30 days and 29 days succeed each other, adding up over two successive months to 59 full days. This leaves only a small monthly variation of 44 minutes to account for, which adds up to a total of 24 hours (i.e., the equivalent of one full day) in 2.73 years. To settle accounts,
STS-74 was performed on orbit 128 at around 11:00 am EST (16:00 UTC), leading to a landing at Kennedy Space Center (KSC), Florida, on Runway 33 of the Shuttle Landing Facility. The main landing gear touched down at 12:01:27 pm EST (17:01:27 UTC) on 20 November, a mission elapsed time (MET) of 8 days 4 hours 30 minutes and 44 seconds. Nose gear touched down at 8 days 4 hours 30 minutes 54 seconds (12:01:37 pm EST – 17:01:37 UTC) and "Atlantis"'s wheels stopped at an MET of 8 days 4 hours 31 minutes 42 seconds (12:02:24 pm EST – 17:02:24