Apollo 11 Lunar Surface Journal

 

Neil's Path from the EASEP to Little West Crater

Copyright © 2009 by Scott Cruickshank.
All rights reserved.
Last revised 23 April 2010.

Editor's Note: Journal Contributor Scott Cruickshank provided this analyis on 14 January 2009, calling attention to the need for correction of the path Neil Armstrong took to Little West Crater as it was shown in the the traverse map (Fig. 3-16) in the Apollo 11 Preliminary Science Report and in a refined, 1978 site map (shown below) produced by the USGS and airbrush artist Patricia M. Bridges of the Defense Mapping Agency.  Lunar Reconnaissance Orbiter was launched 18 June 2009, After about three months of calibration and testing in a higher orbit, on 17 September the spacecraft was placed in its mapping orbit, a polar orbit 50 km above the lunar surface which is low enough to provide 0.5 meter per pixel resolution and, under favorable lighting condition with the Sun overhead, to show the tracks the Apollo crews made during the EVAs.  An Apollo 11 image captured on 1 October 2009 (bottom of the page) that clearly showed the Apollo 11 tracks.  The image was released on 9 November.


I believe that the Apollo 11 traverse maps have the position of Neil Armstrong's traverse to Little West Crater plotted incorrectly.  This first occured to me when I noticed  that Armstrong's outbound footprints are visible in one photo he took from the crater, AS11-40-5961,  and in one he took about halfway back to the LM, AS11-40-5962.  The footprints and disturbed soil can be seen a little better if the photo is darkened in an image editor.   In each of the photos, the bootprints and disturbed soil are visible in front of Armstrong. 

Labelled detail from 5961


Detail from AS11-40-5961, the last photo in the pan Neil took from the rim of Little West Crater. Some foreground footprints and/or patches soil mounded at the front of a footprint are circled in red. A corridor of disturbed soil, which tends to be darker than undisturbed soil close to the LM,  is delineated in red. (Click on the image for a larger version.)


If the Apollo-era traverse maps were correct, the outbound bootprints should not have been visible (see panel A, below).  They would have been well outside the field-of-view of the camera to the left.  Instead, Armstrong's outbound and inbound foot trails were along the same path from about the halfway point out to the crater and then back (see panel C, below).


Outbound track in 5961 and 5962


This whole thing appears to hinge on a misunderstanding as to where exactly Armstrong began his traverse to Little West Crater.  The Apollo era maps have it beginning at the Passive Seismic Experiment Package (PSEP), which is wrong.  It actually began from an area around the Laser Ranging RetroReflector (LRRR) which was about 10 meters farther north.  The reason for this is that Armstong had to retrieve the Apollo Lunar Surface Close-Up Camera (ALSCC) before he could leave the LRRR/PSEP site.  The reason is that, after taking final documentation photos of the deployed LRRR (AS11-40-5952, panel D, above) and the PSEP (AS11-40-5953), he went back to the LRRR to grab the ALSCC which, as can be seen in both photos,  he had left that on a rock next to the LRRR.  Once he had the ALSCC in hand, he began his run to Little West Crater.


The video provides additional evidence that Neil began his run from the vicinity of the LRRR.   Specifically, we know that the both the LRRR and PSEP were deployed just out of the TV field-of-view to the right.  The LRRR was deployed 40 meters from the TV camera, while the PSEP was deployed about 7.5 meters farther away along virtually the same azimuth.  At about 110:58:55, Buzz carries the two package off camera to the right and, after looking around for a moment, puts the LRRR "on the other side of this rock."  Neil has been following along behind, taking Hasselblad pictures, and holding the ALSCC out in front.  Shortly after 110:59:28, He pauses for about 16 seconds, right at the edge of the field-of-view, with only his PLSS visible.  As he starts moving again, going completely off-camera, he gives a detailed description of the boulders he's been seeing, probably having just taken those 16 seconds to examine the one near the LRRR in detail.  It also seems likely that he took some or all of the last five of the close-up stereo images (AS11-45-6709-14) of that boulder and then left the ALSCC in place on the boulder while he got started on the LRRR deployment. 

Editor's note:  Journal Contributor Vladislav Pustynski has identified this boulder in two images Neil took out his window after the EVA, AS11-37-5549 and AS11-39-5842.  Vlad has also pinpointed the boulder's location as part of a 2010-11 photogrammetric revision of the site map.


In Panel E, above, images 1 and 2 are TV frames as Buzz and Neil leave the field-of-view near the LRRR.  At about 111:07:27 runs into the field-of-view, stopping when he is about on the same line-of-sight as the outer edge of the plus-Z footpad and turning back to make a visual check of the PSEP antenna alignment.  As can be seen in TV frame 3 in Panel E, Buzz's image in noticeably shorter than in image 1.  The extra distance from the TV camera should reduce his apparent height by about 20 percent.  Buzz then goes back toward the PSEP and off-camera.  Finally, at 111:10:55, Neil appears at the right edge of the screen, pausing briefly as he grabs the ALSCC and then starts his run to Little West.  When he first comes into view, we just see the back of his PLSS.  He is stationary for a few seconds and, as he comes fully into view, he is turning to his left, with the ALSCC in his trailing, left hand.  He quickly moves The ALSCC out in front.  As can be seen in image 4 in Panel E, he is at about the same distance from the TV as he and Buzz were in images 1 and 2.  (It is possible that he took the final ALSCC images at about the time he re-appeared.)


To sum it all up, Armstrong's last act at the LRRR/PSEP site was to grab the ALSCC.  From that point he traversed to the Little West Crater,  then returned back to the LM along the same path, at least as far as the spot where he took AS11-40-5962.


Editor's note:  The essential features of Scott's analysis are confirmed by a high-resolution (0.5 m/pixel) image taken by the Lunar Reconnaissance Orbiter Camera (LROC) on 1 October 2009 at local noon.  The bright object immediately east of the LRRR is a cover Neil removed from the reflector and then discarded, as planned, during the deployment.

News flash: A newly released LROC image taken on 5 November 2011 from an altitude of 24 km shows Neil's route in even greater detail.


1 October LROC


Journal Home Page Apollo 11 Journal Index