How long apollo 11 stay on the moon?

Eagle touched down in the Sea of Tranquillity at 20:17:40 UTC on 20 July 1969 and lit its ascent engine at 17:54:01 UTC the following day: 21 hours and 36 minutes on the surface. Most of that time the crew stayed sealed inside a cabin about the size of a small lift, with no seats. The single excursion began when Neil Armstrong opened the hatch and backed down the ladder; he set foot on the regolith at 02:56:15 UTC on 21 July, and Buzz Aldrin joined him some twenty minutes later. The two worked outside together for 2 hours 31 minutes.

Nothing about the schedule was generous, and deliberately so. Nobody knew how a suited human would cope with lunar dust, heat and one-sixth gravity, so the flight plan bought margin everywhere: backpack consumables, the ascent window, the propellant left in the descent stage. In that single excursion the crew planted the flag, took the call from the White House, set out a solar-wind collector, a seismometer and a laser retroreflector, photographed the site and filled two sample boxes. A rest period followed, taken standing, in a cabin that was noisy and uncomfortably cold.

Apollo 12 added a second excursion. By Apollo 15, 16 and 17 the crews had a battery-powered rover, upgraded backpacks and three excursions apiece, and their stays were measured in days rather than hours. Set against those expeditions, Apollo 11 reads as a reconnaissance: land, prove that people could work there, and get off the ground again while everything still functioned. The margin mattered. A circuit breaker needed to arm the ascent engine had been snapped off by a backpack, and Aldrin ended up pushing it in with a felt-tip pen.