Lunar day around the Sun at the same time, the Moon must travel further to return to the same phase. On average, this synodic period lasts 29 days, 12 hours, 44 minutes, and 3 seconds. This is the mean figure since the speed of the Earth–Moon system around the Sun varies slightly during a year due to the eccentricity of its elliptical orbit, variances in orbital velocity, and a number of other periodic and evolving variations about its observed, relative, mean values, which are influenced by the gravitational perturbations of the Sun and other bodies in the Solar System. As a result,
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