Thursday, December 13, 2012

Apollo+40: The Third EVA - "As We Shall Return"

For those who haven't read the plaque, we'll read the plaque that's on the front landing gear of this LM. First there's two hemispheres, one showing each of the two hemispheres of the Earth. Underneath it says "Here Men from the planet Earth first set foot upon the Moon, July 1969 A.D. We came in peace for all mankind." It has the crew members' signatures and the signature of the President of the United States. -- Neil Armstrong, Apollo 11, 109:52:40 GET, July 20, 1969 at the Sea of Tranquility

Lunar Module (LM) Eagle's front landing leg carried that plaque to the Moon to commemorate and mark where Man first set foot upon a world that wasn't his. The journey, wonder, exploration, and discovery on the surface of another world experienced by just twelve representatives of all humanity was about to have its coda.

At 163:32:48 Ground Elapsed Time (GET), 5:25PM Eastern Standard Time, December 13, 1972, Apollo 17 astronauts Gene Cernan and Jack Schmitt depressurized their LM Challenger, opened her hatch, and began their third and final EVA - to date, Man's last trek out onto the surface of another world.
163:41:29 Cernan: Okay, Bob. I'm going down the ladder. 
163:41:31 Parker: Roger, Geno. (Long Pause) 
163:41:46 Cernan: Yup, still there, Jack. "Godspeed the crew of Apollo 17." 
163:41:52 Schmitt: Good. 
163:41:53 Parker: Amen there, Gene. Amen. 
163:41:58 Cernan: Okay, Bob, I'm on the (foot)pad. And it's about 4:30 [CST, time at Mission Control] (on) a Wednesday afternoon, as I step out on to the plains of Taurus-Littrow. Beautiful valley.
The previous day's EVA took Cernan and Schmitt to the Taurus-Littrow valley's South Massif. They made the incredible discovery of orange soil at Shorty Crater. Today, they would use their Lunar Roving Vehicle (LRV) on a traverse to the North Massif, a more than mile-high mountain above the valley, with planned stops at five geology stations.

The pair arrived at Geology Station 6 at 164:51 GET. The main feature of the site was a large boulder observed on pre-landing photos that most likely had tumbled down from higher on the massif. Gene Cernan had named the feature "Tracy's Rock" for his then nine-year old daughter. 

Tracy's Rock. Jack Schmitt collecting samples as Cernan takes the picture.
164:53:11 Schmitt: And this boulder's got its own little track! Right up the hill, cross contour. It's a chain-of-craters track, and it looks like it stops (static) off where it started. It starts in, what looks to be, a lighter-colored linear zone. Trying to give you perspective, it's probably only about a third of the way up the North Massif.
The boulder was actually broken into five large pieces. Samples were taken from around the area including a core tube. Take a moment to look at the full panorama photo from which the above is cropped. It shows the full extent of the feature, the LRV for added scale, and looks down into the valley below. The large mountain on the right is the South Massif, 10 kilometers away.

While Cernan was taking the pictures the panorama was assembled from, he also observed his and Schmitt's lunar home, 3.5 kilometers away.
165:34:53 Cernan: Oh, and there's Challenger! Holy Smoley! (Pause) You know, Jack, when we finish with Station 8, we will have covered this whole valley from corner to corner! 
165:35:18 Schmitt: That was the idea. 
165:35:20 Cernan: Yeah, but I didn't think we'd ever really quite get to that far corner. Not (Station) 2, but this other one (Station 8). And we're going to make it!
If you look at this picture full size, you'll see light reflecting off Challenger's Mylar insulation, in the center, just above Tracy's Rock. To make it around the fullness of the valley though, they'd have to get moving. They had spent over an hour at the site, leaving at around 166:00 GET.

Geology Station 7 and Station 8 were at the base of the Sculptured Hills on the "east" side of the valley. 
View taken by Schmitt of the Geology Station 8 area, with the LRV and Cernan visible
All the astronauts who went to the Moon had spent a lot of time on geology training. Some were more enthusiastic about lunar geoscience than others, but the planetary geologists listening back on Earth were so fortunate to have one of their own experiencing the Moon first hand.
168:04:31 Schmitt: ...intensely shattered in that area, as (are) the ones that are on the walls. I don't see any sign of organization to the blocks in the walls, right now. There's a possibility that, on the west wall, there's an indication that there's slightly darker gray rocks starting about halfway down the crater. And that level is coincident with what appears to be a bench on the northwest wall. And hints of that bench - it's not continuous - but hints of it are around on the north wall and, I think, right below us. Yeah, on the southeast wall. (Pause) The rocks are pretty badly broken in many cases. Well, I haven't seen any real glass yet. Yet. (Pause) We'll start looking at them a little more carefully. Some of them...That looks like a breccia right there in front of us.
This is a clip from sometime during EVA-3, notable because Jack Schmitt has his sun visor up and you can clearly see his face!

Geology Station 9 was the pair's last stop as they made the return drive to Challenger. This site's main feature was Van Serg Crater, another potential volcanic feature. By now though, Cernan and Schmitt were running late. They had been out for 5:20, and there were many tasks to complete back at the LM before they could get back inside. Mission Control ordered them to skip the last planned geology station and return home.

Before Cernan and Schmitt proceeded with their EVA closeout tasks back at Challenger, they took a moment to remind those of us back on Earth that the United States went to the Moon not to claim it, but "in peace for all mankind".

169:43:06 Cernan: Houston, before we close out our EVA, we understand that there are young people in Houston today who have been effectively touring our country, young people from countries all over the world, respectively, touring our country. They had the opportunity to watch the launch of Apollo 17; (and) hopefully had an opportunity to meet some of our young people in our country. And we'd like to say first of all, welcome, and we hope you enjoyed your stay. Second of all, I think probably one of the most significant things we can think about when we think about Apollo is that it has opened for us - "for us" being the world - a challenge of the future. The door is now cracked, but the promise of the future lies in the young people, not just in America, but the young people all over the world learning to live and learning to work together. In order to remind all the people of the world in so many countries throughout the world that this is what we all are striving for in the future, Jack has picked up a very significant rock, typical of what we have here in the valley of Taurus-Littrow. 
169:44:45 Cernan: It's a rock composed of many fragments, of many sizes, and many shapes, probably from all parts of the Moon, perhaps billions of years old. But fragments of all sizes and shapes - and even colors - that have grown together to become a cohesive rock, outlasting the nature of space, sort of living together in a very coherent, very peaceful manner. When we return this rock or some of the others like it to Houston, we'd like to share a piece of this rock with so many of the countries throughout the world. We hope that this will be a symbol of what our feelings are, what the feelings of the Apollo Program are, and a symbol of mankind: that we can live in peace and harmony in the future. 
169:45:50 Schmitt: (Taking the rock as Gene hands it to him) A portion of a rock will be sent to a representative agency or museum in each of the countries represented by the young people in Houston today, and we hope that they - that rock and the students themselves - will carry with them our good wishes, not only for the new year coming up but also for themselves, their countries, and all mankind in the future. Put that in the big bag, Geno. 
169:46:24 Cernan: We salute you, promise of the future.
Next, they unveiled the bookend monument to Man's exploration of the Moon: a plaque which mirrors the one from Apollo 11's EVA, left three and a half years before in the Sea of Tranquility:

169:46:38 Cernan: (Taking the rock and returning to the Rover) And now - let me bring this (TV) camera around - to commemorate not just Apollo 17's visit to the Valley of Taurus-Littrow but as an everlasting commemoration of what the real meaning of Apollo is to the world, we'd like to uncover a plaque that has been on the leg of our spacecraft that we have climbed down many times over the last 3 days. 
169:47:19 Cernan: And I'll read what that plaque says to you. First of all, it has a picture of the world. Two pictures. One of the North America and one of South America. The other covers the other half of the world including Africa, Asia, Europe, Australia, covers the North Pole and the South Pole. In between these two hemispheres, we have a pictorial view of the Moon, a pictorial view of where all the Apollo landings have been made; so that when this plaque is seen again by others who come, they will know where it all started. The words are, "Here man completed his first exploration of the Moon, December 1972 A.D. May the spirit of peace in which we came be reflected in the lives of all mankind." It's signed, "Eugene A. Cernan, Ronald E. Evans, Harrison H. Schmitt, and most prominently, Richard M. Nixon, President of the United States of America." This is our commemoration that will be here until someone like us, until some of you who are out there, who are the promise of the future, come back to read it again and to further the exploration and the meaning of Apollo. 
The plaque, pre-flight. 
169:48:57 Parker: Roger, Gene. We in Houston copy that and echo your sentiments. Dr. (James) Fletcher (the NASA Administrator) is here beside me. He'd like to say a word to the two of you. 
169:49:09 Fletcher: Gene and Jack, I've been in close touch with the White House, and the President has been following very closely your absolutely fascinating work up there. He'd like to wish you Godspeed as you return to Earth, and I'd like to personally second that. Congratulations. We'll see you in a few days. Over. 
169:49:35 Cernan: Thank you, Dr. Fletcher. We appreciate your comments, and we certainly appreciate those of the President. And whether it be civilian or military, I think Jack and I would both like to give our salute to America. 
169:49:53 Schmitt: And, Dr. Fletcher, if I may, I'd like to remind everybody, I'm sure, of something they're aware, but this valley of history has seen mankind complete its first evolutionary steps into the universe: leaving the planet Earth and going forward into the universe. I think no more significant contribution has Apollo made to history. It's not often that you can foretell history, but I think we can in this case. And I think everybody ought to feel very proud of that fact. (Pause) Thank you very much.

Schmitt was then dispatched to the Apollo Lunar Surface Experiments Package (ALSEP) gear that was placed during EVA-1 two days before to make some final adjustments and return some experimental equipment. While Schmitt did that, Cernan drove the LRV a short distance away from where its television camera could capture Challenger's lunar liftoff the following day. Cernan removed the fender repair from EVA-2 (the clamps holding it were needed in the LM) and snapped off part of the left rear fender as a souvenir. LRV-3 had served Apollo 17 well: 4:26 of driving, odometer at 22.3 miles driven. The furthest distance Cernan and Schmitt ventured away from the LM was 4.7 miles.

The LRV in its final position, Challenger in the background
Before returning to the LM, Cernan knelt down in his bulky suit and, with his lunar gloved finger, traced "TDC" in the dust - his daughter's initials.

Geologist Jack Schmitt had one last thing he wanted to do on the surface. He took the geology hammer they had used for sample collection and surface work and hurled it.
Apollo 17's geology hammer, in flight
The TV wasn't the clearest as the LRV was parked far away, but here's Jack Schmitt's throw.

Cernan and Schmitt began the final tasks of loading what they'd be taking home back into Challenger. Mission Control urged them on, as they were down to less than 15 minutes of consumables in their life support packs at this point. Schmitt boarded the LM and was onboard at 170:38. The final samples, gear, and equipment were passed up the ladder, and then the last man to walk on the Moon, was alone on the surface.
170:41:00 Cernan: Bob, this is Gene, and I'm on the surface; and, as I take man's last step from the surface, back home for some time to come - but we believe not too long into the future - I'd like to just (say) what I believe history will record. That America's challenge of today has forged man's destiny of tomorrow. And, as we leave the Moon at Taurus- Littrow, we leave as we came and, God willing, as we shall return, with peace and hope for all mankind. "Godspeed the crew of Apollo 17."
I couldn't find a good embed video for Cernan's words, but you can listen on Spotify, starting at 9:03 of the recording. Man's last step was taken at approximately 170:41:55 GET, 12:34AM EST, December 14, 1972. Challenger was repressurized and the final EVA ended six minutes later.

The Wright Brothers first put Man in powered flight almost exactly sixty-nine years before: December 17, 1903. Sixty-nine years from Man's first flight (twelve seconds duration, ten feet in altitude, 120 feet  in distance) to the end time of Man's last Moon walk.

The Human race's time walking on another world was over. Cernan's "not too long" now stands at forty years and rising. 

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