Apollo 8: Difference between revisions - Wikipedia

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The last major event before Lunar Orbit Insertion (LOI) was a second mid-course correction. It was in [[Retrograde and direct motion|retrograde]] (against the direction of travel) and slowed the spacecraft down by {{convert|2.0|ft/s|m/s|abbr=on}}, effectively reducing the closest distance at which the spacecraft would pass the Moon. At exactly 61 hours after launch, about {{convert|24200|mi|km}} from the Moon, the crew burned the RCS for 11 seconds. They would now pass {{convert|71.7|mi|km}} from the [[Geology of the Moon#Lunar landscape|lunar surface]].{{sfn|Orloff|2000|p=46}}

At 64 hours into the flight, the crew began to prepare for Lunar Orbit Insertion{{nbsp}}1 (LOI-1). This maneuver had to be performed perfectly, and due to [[orbital mechanics]] had to be on the far side of the Moon, out of contact with the Earth. After Mission Control was polled for a "[[Launch status check|go/no go]]" decision, the crew was told at 68 hours that they were Go and "riding the best bird we can find".<ref name="journal day 3 LOI">{{cite web |url=https://history.nasa.gov/ap08fj/11day3_black_approach.htm |title=Day 3: The Black Team—Approaching the Moon |last1=Woods |first1=W. David |last2=O'Brien |first2=Frank |date=April 22, 2006 |work=Apollo{{nbsp}}8 Flight Journal |publisher=NASA |access-date=February 7, 2008 |archive-url=https://web.archive.org/web/20080204015340/https://history.nasa.gov/ap08fj/11day3_black_approach.htm |archive-date=February 4, 2008 |url-status=dead }}</ref> Lovell replied, "We'll see you on the other side", and for the first time in history, humans travelled behind the Moon and out of radio contact with the Earth.<ref name="journal day 3 LOI"/> Frances "Poppy" Northcutt, who was the first woman in NASA's mission control and helped calculate the return to earth trajectory for this mission, recounts what it was like when they went behind the moon for the first time in an interview: "That was a very nerve-racking period on the team I was on, and I think it was a very nerve-racking period in general because of this thing with losing signal. You’ve got this big mystery going on there on the backside of the Moon. You do not know what’s happening and there’s not a darn thing anybody here can do about it until we hear from them"<ref>{{Cite web |date=11/14/2018 |title=NASA JOHNSON SPACE CENTER ORAL HISTORY PROJECT

EDITED ORAL HISTORY TRANSCRIPT |url=https://historycollection.jsc.nasa.gov/JSCHistoryPortal/history/oral_histories/NorthcuttFM/NorthcuttFM_11-14-18.pdf}}</ref>

With ten minutes remaining before LOI-1, the crew began one last check of the spacecraft systems and made sure that every switch was in its correct position. At that time, they finally got their first glimpses of the Moon. They had been flying over the unlit side, and it was Lovell who saw the first shafts of sunlight [[wiktionary:oblique|oblique]]ly illuminating the lunar surface. The LOI burn was only two minutes away, so the crew had little time to appreciate the view.{{sfn|Lovell|Kluger|1994|pp=48–49}}