Intrepid Descends
This image from the Apollo Lunar Surface Journal shows the Apollo 12 lunar module, Intrepid, prior to descent on 19 November 1969. The two large foreground craters are Ptolemaeus and Herschel. Richard Gordon took the image from the Command Service Module, Yankee Clipper, as his colleagues aboard Intrepid, Charles “Pete” Conrad and Alan Bean prepared for the second human mission to the Moon.
Don’t forget we need your help to measure craters in the Apollo 12 region for the latest round of Moon Zoo science.
Apollo 12 – a new challenge is set!
Dear MoonZoo aficionados,
Our next surveying exercise will be centred on the Apollo 12 landing site.
Your previous and successful endeavour saw hundreds of thousands of craters and interesting features noted in the region of the Apollo 17 landing site in the Taurus-Littrow valley. Here we witnessed a chaotic and highly scarred terrain, squeezed between tall mountains and crossed by a deep fault (the Lee-Lincoln Scarp): a rather complex geological setting. Indeed, the landing site was selected based on its geological diversity, with the aim of collecting pre-Imbrian age highland material, mare basalts, and igneous products from potential volcanic edifices.
Apollo 12 – Commander Pete Conrad is working at the equipment bay of Lunar Module ‘Intrepid’ on the Ocean of Storms (mission patch and image ©NASA)
Now we are turning our attention to the Apollo 12 landing site, and from 9 May all the Moon Zoo images relate to this site. In November 1969 Apollo 12 landed within a vast lunar mare (lava plains) region called Oceanus Procellarum (Ocean of Storms), and in particular an area baptised as Mare Cognitum (Known Sea), so called given that it had already been visited by three unmanned lunar missions (Luna 5, USSR, Surveyor 3 and Ranger 7, US). The landing region was estimated to be younger than the Apollo 11 site based on kilometre-size craters census (2.37 times fewer craters). In the following years, returned sample analyses (i.e. Stöffler and Ryder, 2001; Barra et al., 2006) estimated ages of 3.58 ± 0.01 and 3.80 ± 0.02 Gyr (both Late Imbrian Epoch), for Apollo 11, against 3.15 ± 0.04 Gyr for Apollo 12, (Eratosthenian Period). It will be very interesting to compare these direct age estimates with your high resolution/volume crater count survey, AND also compare them with the results from the Apollo 17 blitz (samples’ age: 3.75 ± 0.01 Gyr).
Obviously, as before we are also going to harvest data generated by the Moon Zoo users regarding bouldernyness and shape of the noted craters in order to build a fuller picture of the impact record in the region. As it happens, the lunar science team based at Birkbeck/UCL, UK, has been looking at the Apollo 12 region for quite sometime, both in terms of geological mapping and analysis of returned samples. We are particularly interested in the different lava flows found in the region and the mapping of small craters; the associated boulder distribution will be employed to estimate the different ages and thickness of these lava flows. Your Moon Zoo measurements of the Apollo 12 site will therefore be greatly appreciated, and they will potentially be incorporated in future scientific publications.
So, let’s start this new and exciting journey together: I will keep you posted on both results from previous efforts (A17, etc.) and the ongoing ones. Go and explore!
Barra F., et al., 2006. 40Ar/39Ar dating of Apollo 12 regolith: Implications for the age of Copernicus and the source of nonmare materials, Geochimica et Cosmochimica Acta 70, 6016-6031.
Stöffler D. and Ryder G. 2001. Stratigraphy and isotope ages of lunar geologic units: chronological standard for the inner solar system. Space Science Reviews 96: 9-54.
Apollo 12 and Surveyor 3
Here is a seldom posted photograph showing Surveyor 3 from Block crater which is a small crater just inside the rim of Surveyor crater. The Apollo 12 lunar module Intrepid, not shown, would be behind astronaut Alan Bean who took the photograph. Notice the astronauts’ path in the regolith at top of Surveyor crater moving along the rim. Click on NASA link below for an incredible view (click on photo to magnify). Apollo 12 landed on the Ocean of Storms on November 19, 1969.
http://history.nasa.gov/alsj/a12/a12pan1344009rdmh.jpg
http://www.lpi.usra.edu/lunar/missions/apollo/apollo_12/surface_opp/
Below is a photograph mosaic taken by Surveyor 3 that shows Block crater right of center. Surveyor 3 landed on April 20, 1967. Its camera is pointed in the direction where Alan Bean would be standing and aiming his camera at Surveyor 3 two and a half years later. Here is a contour map of Surveyor crater.
http://history.nasa.gov/alsj/a12/NASA67-H-876-s.jpg
Surveyor 3 made scoop marks in the lunar regolith that were recorded with its television camera. 31 months later (see diagram of scoop marks) the Apollo 12 astronauts photographed them.
http://history.nasa.gov/alsj/a12/AS12-48-7107.jpg and http://history.nasa.gov/alsj/a12/AS12-48-7098.jpg
The scoop mark in right photograph is just below the footprint. At Moon Zoo we know that these disturbances of the regolith last a very long time and can be seen in many MZ photographs such as the landing site photograph featured later in this article. Here is what the Apollo 12 Surface Journal says:
“Post-mission analysis indicated that, in the 31 months since Surveyor landed, no meteoritic craters larger than 1.5 mm in diameter had been created in the bottom of the footpad imprint or in the areas disturbed by the Surveyor scoop. The analysis also did not show any signs of weathering over 31 months. Erosion of features by the steady rain of small meteorites is an extremely slow process.” You can also click here to read an analysis of Sureyor 3 material returned to Earth.
Lateral Lines in Survey Crater
The astronauts came across some very interesting lateral lines in Surveyor crater that they could not explain. This is what they said:
133:58:51 Conrad: Oh, that is interesting! What in the hell…
133:58:52 Bean: Look at how it’s kind of made them into…Once again, it looks like something has rained on it. They’ve taken on a little…
133:58:58 Conrad: Wonder if that was from us?
133:59:00 Bean: Oh, no! I don’t think so. (Pause) Hey, you notice, there’s a general trend of lines along here from the north…that would be the northeast to the southwest. See those little lines running along through the crater here?
133:59:15 Conrad: Yeah.
133:59:16 Bean: I think I’ll take a picture of that. (Pause)
Alan Bean photographed the lateral lines below and I cropped and enlarged them to show more detail. There are several of them running along the crater and I bracketed a couple between the white lines. Surveyor 3 scoop is shown on the left. The dark stuff is shadow.
At the Moon Zoo Forum, we often share interesting photographs that give clues to what is happening on the lunar surface. ElizabethB submitted this Moon Zoo photograph below. What Pete Conrad and Alan Bean may have been looking at were mini boulder tracks running through Surveyor crater.
Forum member Caro made an outstanding composite photograph from Moon Zoo Apollo 12 pics below. Surveyor 3 is on left side of crater (large crater left in MZ composite photograph) about half way down. You can follow the footsteps from the lunar module descent stage. NASA LROC article, ” First Look: Apollo 12 and Surveyor 3″ with more information.
The craters seen from lunar orbit were called Snowman and used as a landing aid. Surveyor crater was the snowman’s main body. The photo below is what Richard Gordon saw looking through his sextant from the orbiting command module Yankee Clipper. You will need good eyes. Luckily an annotated version was made. This link takes you to a NASA diagram of Apollo 12 mission ground tracking of Intrepid as it makes its approach and lands near Surveyor crater.
Apollo 12 mission commander Pete Conrad was a colorful individual who left a enduring legacy at NASA. His biography, “Rocket Man” by Nancy Conrad and Howard Klausner is well worth reading. Alan Bean was his lunar module pilot and later became an artist. This video is an excerpt from an an excellent documentary on the lightning strike during Apollo 12 lift off and the near abort.
I think you will enjoy Alan Bean’s art gallery of Apollo missions. Click on the “Entrance” icon and go to the index of collections.
Tom128 is a regular contributor to the Moon Zoo Forum.
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