4.7.5 - Apollo 15 Day 5 - Orbit

The next image to be examined for this mission is from magazine 87. AS15-87-11722 (along with a duplicate image after it) shows a distant Earth between a series of images that show the landing sequence as shot from the LM. Figure shows the photograph.

The first five images in this magazine show a distant CSM, and the timeline shows that undocking of the LM and CSM occurred at 18:13 on the 30th.  Following this are several orbital images, including one set showing Hadley Rille, the ultimate landing area. Immediately following the photographs of Hadley Rille are the two Earth images described. These are then followed by other orbital images (including Mare Smythii) before the surface is photographed. The landing itself occurred at 22:16 on the 30th, so we have a relatively narrow window within which to look for satellite matches.

If only it could be so simple! July 30th is missing from the original ESSA data catalogue.

Normally when a day's records are unavailable as a result of some technical issue, a blank page will be inserted stating that there is no record. In this case there is no such page, and there are no orbits missing in the record of passes in the Appendix. The obvious conclusion is that it has been missed out in error. Other pages were checked to see if there was a duplicate July 30th, but none was forthcoming.

What is available, however, are the ESSA mosaics from the 29th and the 31st, which should allow us to interpolate which weather patterns can be seen on the Apollo image. This is shown in figure We do now have the benefit of a digitally restored image from the 30th obtained after the initial analyses were done, and its 3D reconstruction is also included.

Figure  AS15-87-11722.

Figure AS15-87-11722 compared with ESSA images from the 29th (top & bottom left) and the 31st (top & bottom right). SkySafari depiction of time. Right - digitally restored ESSA image from the 30th and a 3D reconstruction. Left is the ESSA satellite image from the 30th as printed in the Sarasota Herald Tribune in the 31st.

Two factors are making life difficult with this image comparison. Firstly, the fuzziness of the Apollo image, and its overexposure, means that it is difficult to pick out the weather systems that make out the bulk of the image over central America and off the coast of south America. Secondly, the satellite image itself appears to be under-exposed, so that those weather systems that are visible are not there in their entirety. This is less of an issue when the satellite image is from the same day as the Apollo image, but when we are having to interpret data between two days it can be difficult.

Despite this, there is a good correspondence between the three images, and it does not seem unreasonable to suggest that the Apollo image represents the mid-point between the two ESSA images. As further corroboration, the photographic index records this image as being taken on orbit 13, which the mission transcript identifies as starting at 19:20 on the 30th. 

The photographs immediately before the Earth ones are of the Hadley Rille landing site, which is roughly where I’ve positioned them in SkySafari. The photographs immediately following these two Earth images shows Mare Ingenii, a far side feature recorded as in orbit 14, as are the images of Mare Smythii immediately before the images taken on the ground. LOS on orbit 14 is almost exactly at 21:00 on the 30th, so the estimate of 20:45 seems like a good one. The fact that we now have a digitally restored version of the image from the 30th confirms our estimates even more.

That’s it for this magazine, and this day. The next shots are from the Command Module on the 31st

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