July 20, 1969: “The Eagle has landed”


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An evening pause: In honor of the fiftieth anniversary.

Note the calm tone in all the voices, even when something is not quite right. To do really great things, one must not let one’s emotions run the show. You need to be cool-headed and focused on the task at at hand. If only today’s adult generation, especially in the world of politics, would do the same.

Just before Armstrong brings Eagle down, you will hear a voice say “60 seconds,” then “30 seconds.” That is mission control telling him how much time they estimate he has before he runs out of fuel.

Below the fold is the same last few minutes of the landing, produced by the Lunar Reconnaissance Orbiter (LRO) science team using its high resolution images to recreate a simulation of what Armstrong saw in his window. Remember, the view in the original 16mm film was out Aldrin’s window.


As the LRO team notes,

As the video begins, Armstrong could see the expected landing point was on the rocky northeastern flank of West crater (190 meters diameter), leading him to take manual control and fly horizontally, searching for a safe landing spot. At the time, only Armstrong saw the hazard; he was too busy flying the LM to discuss the situation with mission control.

After flying over the hazards presented by the bouldery flank of West crater, Armstrong spotted a safe spot about 500 meters down track where he carefully descended to the surface. Just before landing, the LM flew over what would later be called Little West crater (40 meters diameter) and Armstrong would visit and photograph this crater during his extra-vehicular activity (EVA). Of course, during the landing, Armstrong was able to lean forward and back and turn his head to gain a view that was better than the simple, fixed viewpoint presented here. However, our simulated movie lets you relive those dramatic moments.

Note that in the LROC NAC image, the LM descent stage and astronaut tracks are of course visible — something Armstrong did not see during the landing! The incidence (solar) angle on the NAC image is within a degree of the lighting when Apollo 11 landed (just after sunrise), so you see the same dramatic shadows.

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12 comments

  • ” . . . he was too busy flying the LM to discuss the situation with mission control.”

    Aviate, navigate, communicate.

    Neil Armstrong was The Man.

    (Could someone hack the Google Doodle and fix the astronaut’s left shoulder?)

  • wayne

    I like this version….

    Apollo 11 Descent:
    Film and LRO Imagery side-by-side
    NASA 2013
    https://youtu.be/YKXw_3Pblh8
    4:51

  • wayne

    Blair–
    Nicely written Post at your Blog!

    A repeat from me–

    Behind the Apollo 11 on-board computer
    NASA programmer Don Eyles
    July 15, 2019
    https://youtu.be/z4cn93H6sM0
    7:17

  • wayne

    “As Time Goes By”

    “This day and age we’re living in, gives cause for apprehension.
    With speed and new invention, and things like fourth dimension.
    Yet we get a trifle weary, with Mr. Einstein’s theory.
    So we must get down to earth at times , relax relieve the tension.
    And no matter what the progress , or what may yet be proved.
    The simple facts of life are such, they cannot be removed.”

    (It’s still the same old story, a fight for love and glory, a case of do or die….)

  • wayne

    –extremely well done:

    Annotated Apollo 11 landing- PDI to Touchdown
    Apollo Flight Journal 2014
    https://youtu.be/RONIax0_1ec
    14:57

  • wayne

    BBC James Burke
    Apollo 11 retrospective on the moon landing
    1979
    https://youtu.be/8XuJj1zXkDw
    7:45
    –includes flight-director’s audio loop during landing

  • Jim Davis

    Just before Armstrong brings Eagle down, you will hear a voice say “60 seconds,” then “30 seconds.” That is mission control telling him how much time they estimate he has before he runs out of fuel.

    This is a common misconception. The times actually refer to how much time Armstrong has before he can no longer abort the landing; he will then be absolutely committed to landing the LM. An abort at this stage of the landing sequence required a full thrust descent engine firing which would gain enough altitude for the ascent engine to be readied for firing before crashing on the moon.

    So when the Eagle landed it was actually about 15 seconds from entering the so called “dead man zone” when it must land or crash. It was not 15 seconds from running out of fuel.

  • Jim Davis: Can you provide me a source? I suspect you are right and I am wrong, but I want a confirmation.

  • Jim Davis

    If memory serves I read this in Chariots for Apollo: The Making of the Lunar Module by Charles R. Pellegrino and Joshua Stoff (not to be confused with the official NASA history also entitled Chariots for Apollo.

  • Jim Davis: When I get home tomorrow I will take a look, as I have it in my home library..

  • Regarding the “bingo” fuel call: see https://www.hq.nasa.gov/alsj/a11/a11.landing.html

    When that timer gets to zero, there is still some fuel remaining: “…Neil will have 20 seconds to land, if he thinks he can get down in time. Otherwise, he will have to abort immediately.” As Jim Davis indicated, it requires some descent engine fuel to perform the abort.

    On that page there’s a wonderful quote from Armstrong about what he was thinking during the landing, and his estimate for how high up they could be when fuel runs out, and still land successfully:

    “I did know that if I could have my speed stabilized and attitude stabilized, I could fall from a fairly good height, perhaps maybe forty feet or more in the low lunar gravity, (and) the gear would absorb that much fall. So I was perhaps probably less concerned about it than a lot of people watching down here on Earth… I would certainly prefer that drop to trying to go through the abort sequence at that altitude.”

  • wayne

    Jim/Steve-
    Good stuff.

    Mr. Z.,
    as well, check the annotated PDI to Touchdown video.

    https://youtu.be/RONIax0_1ec?t=755

    “When their Quantity light comes on, MCC reckon they will have 5.6% or 114 seconds of fuel remaining.”
    “MCC begin a 94 second count that leads to a ‘bingo’ call; either land or abort now.”

    –the module then lands approximately 20 seconds before the bingo call.

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