Harrison Schmitt, “A Trip to the Moon" - Mass Space Grant Consortium Public Lecture
MODERATOR: Good afternoon, and welcome to the Sixth Annual Space Grand Public Lecture sponsored by the Massachusetts Space Grand Consortium. Our speaker this afternoon has traveled further than anyone has, and most likely will ever travel, to give this lecture. Jack Schmitt went to the Moon and back, and he's going to tell us a little bit about that.
Now, for the benefit of those in the audience who don't have any gray in your hair, put yourself back into the mindset of the American population in the late '60s, and the excitement that was generated throughout, not just in the MITs and the Harvards and the Caltechs and the Stanfords of the world, but throughout the community about the excitement of preparing for probably the boldest human space exploration of all time. It, of course, reached its initial excitement in the footstep that everybody remembers with Neil Armstrong and our alumnus Buzz Aldrin. And it continued on through a science gathering activity, which has, in many ways, never been repeated in the history of the space program, culminating with the first scientist to walk on the Moon, our speaker today, who was also-- and this is somewhat ironic to look back upon it-- the last man to walk upon the Moon.
Jack Schmitt, who was a good friend to many of us here in Cambridge, began work as a geologist, and he had a very promising career as a geologist. And when he was selected by NASA as an astronaut to train for the Apollo program, and performed the way many of us had always hoped scientists and engineers in space would perform in the course of his exciting exploration of the Moon. Beyond that, after return, and after some important work with the space agency, he went on to another challenge, in many ways just as great, and that is in attempting successfully, to a great extent, to have his ideas carried forward to fruition for the benefit of all of us as a member of the United States Senate, a Senator from his home state of New Mexico.
And since that period of time, Jack has remained active in a number of areas, including the space arena where we continue to bump into him. I'd be happy to say, we're usually on the same side of the vigorous arguments that ensue. And what we have asked Senator Harrison Schmitt to do today in his talk, A Trip To The Moon, is talk about not only what it was like, but what it can be like for the next generation. Senator Schmitt.
SCHMITT: Well, thank you very much, Larry, and I appreciate the introduction, and I also appreciate the opportunity to speak once more at MIT on this subject. I think the last time was about 20 years ago and it was to a roomful of geologists and Earth scientists from MIT and Harvard. So I don't think any of those people are here, and so I'm probably not repeating anything I might have said and I don't have to worry about being consistent.
Larry's exactly right. What I would like to do is to take you on a trip to the Moon. I'm not going to spend a lot of time getting you back. Usually, for many audiences, I do spend some time getting everybody back, but we won't worry about that today.
Because I [AUDIO OUT] briefly summarize the first order understanding of this small planet that we gained as a consequence of the Apollo program. An extremely important consequence, and not one that was anticipated by John F. Kennedy when he challenged the nation to go to the Moon and return safely to Earth, but one which in the process of implementation of that challenge, we realized a great deal could be done and, indeed, a great deal was done. Also, at various points in all of this you'll hear me talk a little bit about what I think the future may hold, not only for the Moon, but in its now increasingly symbiotic relationship with the Earth, and ultimately, with human settlement of the solar system in general.
So with that brief introduction, if we could have the lights down. And the first slide, that's up to me, I guess. Did it go? There we go. And if the speaker light could come down, I think the slides would-- You've all seen me, so you don't need to see me through this whole thing. Can I control that, or could we have the speaker light down? Maybe we can't do that.
At any rate, we began these trips to the Moon in the late '60s and early 1970s from the Kennedy Space Center. And here you see the Saturn V rocket to be used by the Apollo 17 mission, moving away from its assembly building, the vehicle assembly building, towards the launch pad. It is still the largest rocket that has ever been used to put human beings in space. 364 feet high. The basic fully fuel weight was 6.2 million pounds. And the five big engines in the first stage developed 7.5 million pounds of thrust.
Now, the Space Shuttle approaches those numbers, but does not reach them. And it was, indeed, exactly what we needed for this mission. A truly remarkable accomplishment is putting this system together, and one which worked with extraordinary reliability each time we demanded something of it. By the way, that vehicle assembly building is now fully utilized, unlike in the Apollo program, fully utilized by the activities of the Space Shuttle program.
This is just an alternate view of the Saturn V looking from the bottom up. Those of you who can see in the lower right-hand corner, the upper torso of a man. We'll get a feeling for scale here. It's quite a large vehicle. That D on the fin, left-hand fin is about five feet high, I would suspect.
Really awesome, not only from the bottom, but from the top. Here, now looking across the top and the launch escape rocket that is attached to our capsule, that you can see there-- the cone-shaped capsule at the top of the rocket, looking back towards that vehicle assembly building that I mentioned earlier. I generally don't need this, but that's the building out there. We were on our way out to the launch pad at this point, moving at less than a mile per hour on this huge machine we call the crawler. By the way, the crawlers are still used to transport the space shuttles out to the launch pad.
Now, we had many different kinds of training. Thousands of hours, of course, in computer-driven simulators that prepared us for the actual flight portions of our mission. But also, we had things like survival training. And here you see some very young and skeptical looking astronauts learning about the care, feeding, preparation of a boa constrictor at an Air Force station in Panama. Ed Mitchell, MIT graduate, is in that picture, a PhD. I don't know whether-- Charlie Duke, was he?
AUDIENCE: He was my student.
SCHMITT: Yeah. Well Charlie's behind the boa. You might not be able to tell that, but I remember that he was behind the boa.
Now, we also had science training. And as a consequence of the efforts of many people throughout the country, including Bill Brace, here at MIT, and some Harvard professors and some Caltech field geologists, we finally developed, for the last three missions, a comprehensive Earth science training program that prepared pilot astronauts about as well as one I think could ever expect to prepare these, really, already outstanding observers to systematically collect samples, establish their context through verbal description and photography, and to give us the basis for that first order understanding of a second planet that I mentioned earlier.
Here you see Gene Cernan, the commander of the Apollo 17 mission, and yours truly in an exercise near Flagstaff, Arizona, a science exercise. We actually, each time we went out for the most part, [AUDIO OUT] action profiles, but working on the geology, the science, of real Earth problems. Why Gene felt, in this context, it was necessary to wear checkered pants I'm not sure. He was, and I guess he would still say is, a Navy test pilot, and that might explain the checkered pants.
Gene also was the talker on the crew, believe it or not. And here you see us in an exercise involving our actual flight lunar roving vehicle. We were checking out all the, what they call the fit and function of it in our pressure suits, and Gene had come up with something that excited him, and it obviously put me to sleep.
But ultimately, on December 7th, Florida time, in 1972 we left the Earth with a spectacular night launch, I am told. Having just seen Discovery launch at night, I can get some feeling now for what it was like. But, of course, I missed that. And inside the capsule, we were subjected to, at this point, not very heavy Gs, because the initial acceleration is quite slow, but extraordinarily heavy vibration. In fact, the instrument panel, switch panel in front of me as I was lying on my back, was vibrating so much that I could not read the dial. So it was always some question in my mind, why did I go through all those launch abort simulations when I wasn't going to be able to read the dials during that period of time.
Now, on the other hand, had we actually had to abort for some serious problem, I'm sure my adrenaline would have focused my eyes as rapidly as the panel was vibrating and everything would have worked out just fine. It actually took 14 seconds to reach a point about like this, go the length of the rocket. It took two minutes and 45 seconds to get to a full acceleration on the first stage, which was about four g's. That was the greatest acceleration we had during the launch.
But at that point, we, of course, had reached the limit of fuel in the first stage rocket. We turned it off, staged-- that is, dropped it off into the Atlantic-- and then reignited the second stage rocket in a sequence that went from four g's to a minus one and 1/2 g's, as that whole stack actually unloaded a little bit, to a plus one and 1/2 g's, and all of that happened in just over a second. That gets your attention. The checklists bang back and forth, and you know why you're strapped into your couch, because otherwise, you would be banging back and forth at the same time.
But after we went through the second stage and ignited a third stage, which was actually restartable, because we will see that we're going to use it again, the S-IVB. We were in orbit after, as I recall, a little under 10 minutes, and had a chance to briefly look at some spectacular views of this planet Earth. Here, the South Atlantic and its cloud patterns, the Coast of Africa and the sand dunes, and on over the Kalahari Desert looking down at these frost-like patterns, actually turn out to be burn scars-- apparently, fires set by the local inhabitants to improve the grazing for the next season. Over the Indian Ocean and the magnificent thunderheads that one can see there almost any time, particularly at the Intertropical Convergence Zone.
And then to a sunset-- oh, actually, I'm sorry. These are the atolls of the Great Barrier Reef, I believe, near Australia. And the turquoise blue, by the way, shows up extremely distinctly from way, way out into space. Quite a remarkable contrast with the deeper blue of the oceans.
It took 90 minutes to go around the Earth. We were traveling at about 18,000 miles an hour. We'd made two trips around the Earth to make sure all the spacecraft and rocket systems were ready to go to the Moon, and indeed they were. And so at the end of our second trip, and after passing through a sunset, I believe in this case, we ignited the third stage rocket, the S-IVB, began to accelerate over about a five minute period to 25,000 miles an hour. So through a sunrise-- the most spectacular sunrise I've ever seen-- until we were, indeed, on our way to the Moon in nearly perfect trajectory.
At that point, we undocked the main spacecraft, the command and service module-- America was its name-- from the S-IVB rocket, moved away a little bit, turned around, and then moved back in in order to extract the lunar module, Challenger, which you see here tucked away and folded it up in the end of the rocket. This is the docking port and tunnel. We retract that so we all could go to the Moon together.
Now, those bright spots that you see around the S-IVB are pieces of ice. Actually, ice that had condensed from the atmosphere in Florida on the cold fuel and oxidizer tanks of the S-IVB, and came off when we shut down the engine for the last time. Those are probably what my good friend and former colleague John Glenn thought were fireflies over Australia. Now he is the Democratic Senator from the State of Ohio, and that might explain that little anomaly.
The S-IVB sideway, just so you can see what it looked like as it coasted with us at 25,000 miles an hour initially, to an impact on the Moon. Actually, this became a science experiment at this point, because we already had in place a seismic net from the previous missions, and the S-IVB was a source of seismic energy, which we directed in an appropriate location for science and seismology on the Moon.
I can't remember now. I think it impacted after we had gone behind the Moon, as you'll see in a few moments. But once we had the Challenger in tow, we were able to look back at this beautiful planet rapidly receding from us. Here, still filling the window, but eventually not even doing that, and we were able to take this very, very popular picture of our dear planet Earth, showing the entire continent of Africa, most of Antarctica. A hurricane, our typhoon, going ashore here on India, on the subcontinent of India. Mediterranean there, and the fronts that are circling around Antarctica very nicely shown. Really, a spectacular picture. We're all very proud of it. It is still the most requested image from the NASA archives, as you might expect.
The worst use of this picture that I have ever seen was in a-- and I'm even going to mention the name-- a TWA in-flight magazine where it wasn't good enough, like this, and so they moved Australia over here.
There is Australia. This was taken about a day and a half after the picture I just showed you. We were in now, a lunar reference trajectory, as it was called. And that the Earth was turning beneath us, once every 24 hours, and going through a slow phase transition, as you see here, not nearly as full. And here, looking at the South Pacific, you see how brilliantly Australia, as a desert beacon, shows up. And indeed, you could see the deserts and particularly Australia very clearly from the Moon and identify them.
A number of things. Being an amateur meteorologist, I filled the transcripts with all sorts of descriptions and forecasts as we went towards the Moon for three and 1/2 days. I'm sure I put everybody in the mission control center to sleep, but I enjoyed myself. There wasn't much else to do, as you travel out towards space, except make sure you didn't get into trouble.
This is a typhoon in the Philippine Sea, and those spots right there are thunderheads on each of the Philippine islands. Another typhoon was developing around Guam, which nobody knew about, and we were able to tell the world about. And particularly the Air Force was interested because they had recovery airplane flying in that area in support of our mission. This speckle point is an interesting phenomenon, and actually is a way in which visually you can tell what the sea state is. It's always brighter, for example, near continental shores because of the increased wave activity at that point. If you look carefully, that's China up there, and Southeast Asia. This front has just cleared Japan. Japan's not quite so clear and obvious at this point.
And the Earth continues to recede. About three days out, we had another view of Australia, but at this point, we became increasingly aware of a dark looming shape blocking out the star field, as well as the Earth itself when we headed towards orbit. And there you see the mountains of the Moon across our dear planet Earth again.
The first sunrise that we had in the spacecraft behind the Moon is shown here. Actually, it's a sunset on the Moon. We were in a retrograde orbit, so that when we landed on the other side of the Moon, in the valley of Taurus-Littrow, we would have the sun to our back. It made just for better visibility, of course, than flying into the sun itself.
This illustrates a number of properties of the Moon that are of interest. For one thing, you see absolutely no evidence of an atmosphere. Off there on the horizon, the vacuum at the surface of the Moon is about 10 to the minus 12 Torr. Basically, no atmospheric gases at all, although there is a very small and measurable amount of atmosphere. There's no oxidation of iron minerals, so you get none of the colorful features that we're used to here on Earth. But you do have a beauty of contrast, which this picture and others I think will help to illustrate.
Now, the reason I show this picture somewhat out of sequence-- I actually took this on the way home just after we left lunar orbit-- but it's to give you an indication of where we were going. The valley of Taurus-Littrow, which you'll see more of in a moment, cut through a radial valley, cutting through the ring of mountains surrounding this relatively young circular basin called Serenitatis. Serenitatis is 500 kilometers in diameter, somewhat bigger than Crisium, which you see here, but not quite as big as Tranquillitatis, which is the more irregular basin here. Apollo 11, Neil Armstrong and Buzz Aldrin, landed right there. That Tranquility Base is in that vicinity of the Moon. Our landing, as I say, was somewhat North of that.
A better view, a close-up view of the Valley of Taurus-Littrow is shown here. It's that dark bay-like indentation here. It's about 35 miles long, about four and 1/2 miles wide. And those mountains on either side, although seemingly somewhat subdued, rise to 7,000 feet at their highest points. So we landed in this valley, or a point about right there, in a valley deeper than the Grand Canyon of the Colorado. Truly a remarkable demonstration, once again, of the navigational techniques that had been developed by the Apollo program, and in particular, with the assistance and innovation and imagination of the Draper Laboratory, which then was the MIT Instrument Lab. Had they been spun off yet? I've forgotten when they were spun off. Somebody tell me.
AUDIENCE: It was after [INAUDIBLE].
SCHMITT: It was after that when they were spun off. I am privileged to serve on the Board of the Draper Lab now. So I get to come back and thank them as many times as I can remember to do it.
This picture was taken from about 100 miles away. This one from about 15 miles away and in a somewhat lower altitude. We were only about 10 nautical miles above the surface at this point. The landing site is going to be there. This spot right here is the other spacecraft. Ron Evans, who was the third man on our crew, was alone at this point, since this picture was taken from the lunar module, as we prepared for our last orbit and descent to the Valley of Taurus-Littrow. Ron was about a mile ahead and a little bit below us preparing to get out of the way of our descent on the next orbit.
This mountain here is the highest mountain that borders the valley. Again, something over 7,000 feet high. Looking straight down on the valley is of interest. We landed right there, and those of you who are close enough will see a dark shadow or spot there. That is the shadow of the lunar module. Ron actually took this picture as he passed overhead while we were working on the surface. There is a light-colored spot around this area here that was caused by the descent effluence just altering the optical properties of the surface. We've never been able to detect any impregnation of the effluence of the decent engine, just a modification of the surface texture.
This feature here, this plume-like deposit, is the remains of an avalanche that came off the side of the South Massif, that high mountain I pointed out earlier. Very probably in response to material thrown over 2,000 kilometers from the Crater Tycho in the southern part of the Moon. Those of you who look at the Moon once in a while will know that name. It's one of the younger bright halo craters, bright ray craters on the Moon. And it appears as if one of its rays comes all the way up here across Taurus-Littrow, and we are suspecting that that avalanche was triggered by the impact of that secondary debris. The ages, as far as we can tell the age of Tycho, and the age of this, about 30 million years, work out to be approximately right. So that's the present working hypothesis that we, indeed, had evidence, or worked on an avalanche caused by Tycho.
Our traverses, the first excursion we worked primarily around the lunar module deploying the Apollo Science Package, the ALSEP, about 300 meters ahead of the Challenger. We also sampled around craters in this area. The second excursion, though, we got going early, we headed all the way out here about seven kilometers to that point right there, and worked our way over to this dark crater where we found the orange soil, and then back to the lunar module. And the third excursion was over here to visit some big boulders you'll see in a moment. Fact is, I think it's right there. And then back to there. So we traveled about 35 kilometers in the lunar Rover, which I'll show you in a moment, and collected about 250 pounds of samples, several thousand photographs, and generally had, not only a great, enjoyable time, but a fairly productive scientific mission as well.
This is the first view I had out the right-hand window of the Challenger after landing. It's a view over a fairly typical dark, mare surface of the Moon. The scattered blocks of basalt, and the ground up and pulverized basalt that makes up what we call the lunar regolith, that debris layer, or sometimes called soil layer, that covers the Moon. In this valley it averages about nine meters thick. The regolith of the Moon is the source of many potential resources we'll talk about in a few moments, including an energy resource, a light isotope of helium called Helium 3 that is a nearly ideal, environmentally, as well as efficiency, ideal fuel for nuclear fusion.
The metallic object there in the foreground is one of 16 small restartable rockets that we used to control the attitude of the spacecraft when we were in flight. The far edge of the valley there, say that point right in there, is probably about four miles away, something like that. Now, you have to take my word for these distances and sizes and things like that, because there are no telephone poles or trees or houses or anything that you can use for reference. And indeed, astronauts, almost invariably, underestimated the distances, like sometimes you do when you drive in the Western United States. When the air is clear and they have no clear reference of size, you will do the same thing.
The Challenger, our home away from home on the Moon. Really an excellent camp. Not only did the descent stage, the lower half of the Challenger, contain everything that we could need for our particular mission, including the lunar Rover and the Science Packages, and even our food and film. The ascent stage was really a very good camp. Sleeping in one-sixth gravity that you have on the Moon is very comfortable. We had hammocks that provided very good rest. Not enough gravity to make you want to toss and turn, but just enough to feel like you were lying on something, rather than floating.
The food was reasonably good. Certainly better than I've had in some of my field camps that I've worked in as a field geologist. No hot water. We had hot water in the other spacecraft, the America, but we did not have hot water in the lunar module. That just was not provided for, and it was not really necessary for three days on the Moon. And maybe most important for geologists and maybe some others, there are no black flies or mosquitoes to bother you.
This picture was taken from about 75 meters away. Now, you may have already wondered did we ever feel homesick. Well, my answer is no, because anytime I wanted to see home, I could just look up over the-- here, the lunar module, or the nearest mountain and see the Earth only 250,000 miles away. Communications were excellent, just outstanding. We never had any communication problems of any significance whatsoever. And we worked almost as if we were working anywhere else you could imagine here on Earth.
A well-dressed astronaut wears what you see here. The space suit, the backpack, the emergency oxygen supply there, and the man inside weighed, in this case, about 370 pounds, Earth pounds, but on the Moon that would only be about 61 pounds. Mass didn't change, of course, but the weight was quite different. And so it was really quite easy to move around. You had to watch yourself a little bit. Your center of gravity was displaced about two inches towards the back because of the weight of the backpack. You'll see us leaning forward in order to compensate for that. That was very natural to do. Although, Charlie Duke, when he was on the Moon on Apollo 16, decided to demonstrate what it was like to jump straight up, and he forgot that his center of gravity was displaced, and so he rotated out of the view of the camera, and everybody got a pretty good laugh out of that.
If you ever wonder why astronauts are whistling and singing quite a bit while they're working on the Moon is because it's so much easier than training in one gravity. It really is. We were basically pressurized for almost 10 hours for each excursion, each of the three excursions. And the only muscles that really became fatigued were your forearm muscles and the hand muscles. And that's because the glove was just purely a pressure glove, and every time you wanted to move, you had to squeeze against that pressure, 3.5 PSI. And that would be like squeezing a tennis ball continuously. Every time you wanted to do something, you had to squeeze a tennis ball to do it.
That fatigue, these forearm muscles, no matter what you had done to prepare yourself physically, there was just nothing you could do. After about a half hour or so, you would finally realize what your steady state capability was, and you'd proceed from there. But the overall loss of efficiency as a consequence of that was significant. And I hope that someday, maybe some engineer from MIT will figure out how to engineer a glove that more closely duplicates the normal dexterity of the human hand. That's one reason why we put human beings in space is to have that hand attached to a supercomputer called the brain, and something that we haven't yet been able to duplicate any other way.
The rake that you see there was just one of the many tools that we had for collecting a particular style of sample, small samples out of this lunar regolith. But you also see I'm not going to the trouble to grasp that rake, I just rest it against my hand. Again, anything you can do to keep from using your forearm muscles you would do.
Gene Cernan is testing out the lunar Rover, in this case. It weighed about 450 Earth pounds without us or anything else on it. It worked extremely well. Had four wheel independent drive, four wheel independent suspension. It had front and rear wheel steering. You could do either direct or Ackermann steering with it. It just worked remarkably well. Had no problems with the dust because all the joints and bearings were sealed hermetically, so the dust never was able to penetrate into them. Served us extraordinarily well on all three of the missions that it was used on.
Getting on the lunar Rover was not particularly difficult, once you learned the tricks. You stand at the side, jump up into the vacuum with a little bit of leftward translation, and hope that you came down on the seat assigned to you. Commanders tend to get upset when you come down in their seat. It's a little bit like professors, I guess, if they find you in their chair somewhere. They're paid to get upset, so we don't worry much about that.
One thing that lunar module pilots are paid to do, though, is to repair the fenders broken by commanders. On each of our Rover missions, the commander succeeded in breaking a fender off, and lunar module pilots very quickly were instructed on how to repair it. Here you see unneeded photo maps taped together with, you guessed it, gray duct tape. It held the Rover together, just like it's probably holding this building together by now. And it worked very well. And the reason this was important-- it wasn't just a trivial exercise-- is that in one sixth gravity, this debris, when you're driving, would travel just far enough up the wheel to give you a forward rooster tail, and you'd be driving into your own dust if you did not have something to break that trajectory.
This picture you have to look at, because I like to look at it. I never tire of it. It not only brings back the memories of the desert-like quality of the Valley of Tarsus-Littrow or any place on the Moon, really, but it illustrates just the general nature of what we were doing. The lunar Rover off in the middle distance, the basalt boulders around a crater that's actually on the rim of a crater 600 meters in diameter, the largest in the immediate area. Probably a crater formed by those Tycho secondaries-- we're just not sure.
Now we're going to stand on the North side of the valley. The next few pictures will be a rough panorama looking from the East here towards the South. This actually looks along the path we flew to come into the valley. This picture over the top of a very large boulder, with yours truly for scale, actually includes the lunar module. That spot right there is the lunar module, about three and 1/2 miles away with that, again, lightened patch of material at the top of the regolith, quite visible at this point.
These boulders are made up of fragments of rock. They're called breccias. That's a term that geologists use for rocks made up of fragments of other rocks. And it actually, almost certainly, formed as a result of the huge impact that created the Serenitatis Basin, at whose edge we had landed. And it had rolled down the mountain from about a kilometer and a half away, down about a 26 degree slope until it hit a break in slope. Here, we're on about a 20 degree slope. And it broke into five pieces. But you can see here that the near edge of the trench, the boulder track, if you will, that it made as it rolled to a stop, my footprints are coming down there out of sight and up the other side. Those footprints will stay in recognizable form for about a million years. So if you want to leave your footprints in the sands of time, this isn't a bad place to do it. Certainly far more certain than going to Washington.
[LAUGHTER] View of that South Massif, the highest mountain in the local area, that 26 degree slope, constant slope, built-in moguls from small craters that are formed on the surface. I think it'd be a great ski area one of these days. A 7,000 foot vertical drop in one swell foop, that's not too bad. This is what things looked like after we had worked around the lunar module for a while. And the Rover is parked there in its best position for thermal control. A lot of the thermal control was passive. We tried to keep things as cool as we possibly could, but not too cold, because I guess I should mention that, say, a surface like that in direct sunlight would be probably at 200, 250 degrees C, whereas in the shadow, any shadow there, the surface would very quickly be down at about a minus 150 degrees C. So tremendous temperature contrast between the light and shadow. Depending, of course, on the absortivity/emissivity ratio of the particular surface.
But one reason for showing this picture is to illustrate the nature of that debris layer, the regolith, in which our resources are contained. And it's a lot like damp beach sand. It takes a very nice footprint if you're careful with it. You can see these show up very nicely. But you gradually will stir it up. It's slightly cohesive. When you scuff it, you get a little bit of dust, but you also get some clots that spray out from your boot. But gradually, even though it has a very high, in the undisturbed area, out here it has a very high bearing strength. No problem at all driving or walking over it. As you stir it up, of course, it starts to lose that bearing strength, and that's an issue for those of you that some day will design or live in a lunar base. You'll have to make sure that somehow, you create a surface on the regolith, possibly with just aggregate, that doesn't end up being a problem for the long term.
Gene took this picture as we were preparing to leave after our 75 hour stay, and 22 hours outside the spacecraft-- both records, I might presume to say. Pilots like to keep records. I'm reminded of that many times. You see yours truly preparing to go up the ladder with a bag full of samples, as any good geologist should. And Gene, however, was on his way out to park the Rover so it could watch our ascent back into lunar orbit, which if I'm not mistaken, it will be the picture after this one.
This just is a picture out the right-hand window again, after we had completed our adventures, looking towards the science station, which is deployed out in that area about 300 meters away. The tracks of the Rover, and yours truly running back, or skiing, actually, back and forth. Cross-country ski technique works very well on the Moon. You can move at 10, maybe even 15 kilometers an hour if you work at it. Stopping's another problem, but by gliding just over the surface rather than on it, you do very well.
The ascent is not well photographed, and I apologize for that. This is taken off of a television monitor. Gene tried to persuade me to go outside and get a really good picture of liftoff--
--but I was developing some political astuteness even at that point. And we were on our way-- oops. Can we turn that one back? Somebody apparently-- I had to give the number of that picture to somebody the other night and I apparently didn't-- Great. Thank you.
At this point, I just want to summarize, with this picture, some of the historical significance of our activities. I've already mentioned to you that in the history of science we developed a first order understanding of a small planet, chemically very much like our own, with many geological relationships to our own planet. But this was done now by Apollo for the first time. And it's a very significant and detailed scientific understanding of that planet, and has implications for our understanding of our own planet. Particularly, its early history. And particularly, the origins of life on this planet.
The astronaut, and in this case, yours truly with Gene Cernan reflected in my visor, symbolizes for, in the history of technology, one of the, if not the greatest, explosions of know-how that technology has seen. And although done in a spirit, if you will, of competition with the former Soviet Union, nevertheless was done without a direct threat of war. And that technology base continues to benefit us today in many, many different ways.
The flag of the United States symbolizes not only what the country did in and of itself in response to the challenge that was perceived at the time from the former Soviet Union, but also represents, really, what free men and women can do when faced with a challenge that they believe in, and believe the meeting of that challenge is the most important thing they can do with their lives. I'm sure you all have heard, and maybe even use the phrase, well, if you can go to the Moon, why can't you, and then you fill in the blank.
Well, the point is that you can do whatever you put into that blank, if-- it's a big if-- if you can motivate young men and women like yourselves to believe that that's the most important they can do with their lives at that point in time. It may turn out that later on they have second feelings about it, but nevertheless, if the belief is there at the time, you can do almost anything. In fact, I don't know what is beyond us if we have those kind of beliefs.
And finally, in the history of the human species, symbolized by the Earth above the flag, and more appropriately, maybe symbolized by this view of the Earth rising from behind the Moon. We now have both the technological and psychological awareness, I think, to move the human species into space. There are resources that can serve the environment of the Earth on the Moon, particularly as we search in the not too distant future for that necessary alternative to fossil fuels. There are the resources, additional resources, on the Moon that can make human enclaves there self-sufficient. The same applies to Mars. And if we have any kind of long term, and I mean long term species survival instinct, then the enclaves of the human species on those two planets are going to be extraordinarily important to us, as well as what they do to enable the Earth, indeed, to survive itself.
And so Apollo has given us that new opportunity. What we do with that, literally, new evolutionary status is probably very difficult to say at this point. But nevertheless, as a result of the efforts of Apollo, including some people in this room here today, many people in this room here today, we now have options that we never had before and wouldn't have without it.
Now, let's digress, as we walk off the stage here, and digress a bit to the science by itself. Before Apollo, and at the end of the so-called unmanned, literally, automated lunar exploration program, we had a general understanding of the evolution of the Moon. That there was a very old and highly cratered crust, that it had been modified by a large circular impact basins, some more circular than others. The Highland basins were filled with some light-colored smooth planes we didn't understand, and by the way, still don't today. There were almost basaltic lava flows in most of the basins on the near side of the Moon. There were additional volcanic deposits that looked like they had been pyroclastic, that is, the kind of fire fountains that we see today on the island of Hawaii and elsewhere around the planet. And that there was this deep layer of pulverized debris, the regolith, covering all of this that had developed through some unknown period of time since these other events occurred.
Now, after Apollo, we added a great deal of detail, particularly we understand now the timeframe in which these things had happened. The Moon basically began within the limits of measurement error at the same time the Earth began, about four and 1/2 billion years ago, almost 4.6 billion years ago. And that is now taken with the meteorite data as the age of the solar system itself. Early in its history, right at the beginning, near the beginning, there was a magma ocean. Literally the outer, probably 500 kilometers of the Moon was molten, or largely molten, so that it differentiated. That is, as it crystallized, light crystals floated and heavy crystals sank. And so you ended up with a crust made up largely of a light mineral called anorthositic feldspar, anorthosite is what the rock name is used. And underneath that is a mantle of the Moon that is composed largely of olivine and pyroxene.
And anytime I talk about this now, you have to put in your own minds, was that happening on the Earth? The answer is almost certainly yes. That these events were reflected on comparable events on the Earth, the Earth being modified by its ability to withhold a fluid sphere, whereas the Moon could not. But nevertheless, we now have to think in terms of these events or comparable events having occurred on the Earth as well.
Following the solidification of the magma ocean, after maybe 100 million years or less, the highlands begin to retain the evidence of the intense cratering that was going on. Indeed, the highland areas of the Moon are saturated with craters at least 80 kilometers in diameter. That is, mathematically saturated with craters of that size. An unbelievable period of violence in the waning stages of the formation of the solar system. And then at some point, probably beginning about 4.2 billion years ago, large basins began to form.
The old large basins are the irregular ones, and the newer ones, the younger ones-- still very old, 3.9 billion years old or so-- are circular. And that implies in itself that during that period of time, the crust was somehow strengthened. That is an area of debate now of how did that crustal strengthening occur, but there has been isostatic, that is, compensation of the gravity anomalies that would have been associated with these large basins. There has not been compensation of the younger basins. So something strengthened the crust at that point, so those anomalies could last for three, almost four billion years.
In this period of time, the extrusion of the basaltic lavas in the Maria reached its peak and continued for at least a billion years-- we don't know exactly how long that occurred. And then after that things pretty well stopped. If you had been around three billion years ago and been able to look at the Moon, you would have seen roughly what we see today. There would have been bright craters. They would have been different than the ones you see today, but nevertheless, they would have been there.
And during that three billion years, this mature regolith surface developed, and began to accumulate solar wind volatiles, and mostly hydrogen, quite a bit of helium, and then, of course, as part of the helium, the Helium 3. That is of some interest to us now from an energy perspective and an environmental perspective. We, of course, also understand a great deal about the interior of the Moon, as a result of the seismic experiments. We know roughly it's layered character, and from other constraints, pretty much what it's composed of today.
So again, we did learn a tremendous amount about the Moon and its history and the history the Earth as a consequence. I think I'm going to leave it there. If I could have the lights, and if there is time for some questions, I'll be happy to take those. And thank you very much.
Do we have time for questions?
AUDIENCE: Yes, we certainly do.
SCHMITT: okay. Questions? Yes.
AUDIENCE: After completing [INAUDIBLE] book on his fellow astronaut, I was really struck by his epilogue, in which he talked about how the astronauts reflected on their journeys, with their own wide variation in that and what they've done since then. I'm curious if it does or it does not invoke certain emotions for you when you look up in the sky, and how you've been able to move on since then and find the challenges in life.
SCHMITT: Well, the first question, does it invoke-- when I see it in the sky, does it evoke emotions? I must, because I notice it more than I remember noticing the Moon. I mean, it catches my eye, and that's the best I can say. If I go around a building and suddenly I see the Moon, where I'm sure prior to being involved in the Apollo program I didn't see it, or didn't notice it nearly as much. Or in the Monument Valley, suddenly it's there by the side of one of the mesas, and I just notice it.
But as far as any major change as a result of actually going to the Moon, I have to say I don't think there was a change in my-- But the maturing experience of 10 years-- actually, more closer to eight years-- of direct involvement in a environment in which everyone was totally dedicated to success of this particular project, that had a tremendous influence on, not only my life, but my perspectives of what human beings are capable of doing, as I indicated earlier, when challenged and when they believe in the challenge.
I had an advantage over many of the other astronauts, although the vast majority of them went on to very challenging careers, primarily in business, but in some other arenas as well. I also had my science, and part of my transition was based on working on the lunar samples and trying to synthesize, which I still spend some time on today, the results of the Apollo Science Program. So that kept me moving. At the same time, some old friends of Bob Siemens and mine, George Lowe and Jim Fletcher asked me if-- and I may have stimulated the question, but nevertheless, they asked me if I would come to NASA headquarters to work on the transfer of NASA technologies into energy-related activities.
You see, this all was occurring about the same time as the first Arab oil embargo in 1973. And it occurred to all of us that there might be a great deal of application for NASA technologies, Apollo technologies, in the energy field. And indeed, I think there were, and there have been, maybe not as much as I had hoped at the time. But I worked on that for a couple years. And I had always had in the back of my mind, from the time I was a graduate student, really, at Harvard in the 1960s, that getting into politics was something that I probably would look at very seriously, and I began to look at that seriously while I was in Washington in '74, '75, and decided to go back to New Mexico and my home state and run for the senate.
There was never any time in there to sit back and say, gee, what am I going to do next? There was always something on the horizon. And I just would have to say to you that no matter what goals you set for yourself, and I think some of the astronauts fell victim to this, no matter what goals you set for yourself, keep them in context with your whole life. If it's the only thing you have as a goal in your life and you're not thinking about the future at all beyond that, then whether you achieve it or don't achieve it, you're going to be at sea for a while. And I think some of the astronauts discovered that was the case after they'd been to the Moon.
AUDIENCE: Jack, I had a question about the post Apollo model of the Moon. There was an article in Scientific American this summer you probably saw called "The Apollo Legacy," Science Legacy, and it laid out the evidence that said, now we have confidence that the origin of the Moon was the result of a major comet impact on the Earth which released this large mass that became the Moon. And this was followed by a flood of letters in the preceding months, and the months that followed it disputing that. Do you have any thoughts as to--
SCHMITT: I wish I had written one of those letters because I dispute it as well. You can perform some fantastic computer models that make that a plausible hypothesis. Unfortunately, I think there is at least one major bit of geological evidence that that model has a very difficult time explaining, and it has to do with the orange soil that I mentioned briefly earlier. The orange soil was volcanic material, pyroclastic-like, the fire fountains from Hawaii. There is strong geologic and experimental evidence utilizing the orange soil that that came from deep within the Moon. Some components of it came from below that 500 kilometers of lunar melting. And it indicates that below that depth, the Moon is largely undifferentiated. That is, it's primordial material.
For example, the lead, the isotopic composition that's associated with that orange soil, and it comes from those depths is what we call parentless lead. I mean, it's primordial lead. It doesn't have a great radioactive component to it, as you would expect from other things. It also has volatile elements that are depleted in this part of the Moon that was molten at one time, and they're concentrated in the gases that apparently drove this volcanic eruption.
And it's very difficult-- I won't go into all the details-- but it's very difficult for me, and I have not seen a rational explanation from the proponents of the Mars-sized asteroid theory of how you explain having a relatively undifferentiated interior of the Moon if it was knocked off a largely differentiated Earth. I just don't know how that works. So I am a skeptic of that model. It's a good one. It stimulated an awful lot of discussion. That's what's fun about science is developing the models and seeing if they work. And more often than not, they don't. And you go on to the next one.
In this case, I think that we still have some explaining to do. And so I tend to favor, if you say, okay, what's your idea, I think that it's probably a capture phenomenon that when all the evidence is in that we'll find that the Moon was derived in the vicinity of the Earth, because of its overall silicate-dominated composition, but that it was in a separate solar orbit, but one close enough in Earth-crossing orbit, and eventually was captured.
And it turns out, that although in the early days, the calculations indicated that was a very, very, very mathematically, a very special case, it now does not look like it's quite so special. The work on capture by a few people has now indicated that there are probably a number of different ways in which it could be captured into an Earth orbit. So that's where I'm leaning right now is in that direction. It helps to explain a lot of things that I don't think the Mars-sized asteroid will explain. Yes, sir.
AUDIENCE: What were your plans during the mission if there were a solar particle event?
SCHMITT: Depending on the level of the solar particle event, we would try to put as much mass as we could between us and the event. That was the only plan we had. We knew that that was one of the major risks to the health and safety of the Apollo crews, and there was not any planning beyond that. Although there was extensive planning to how to observe a flare. Where on the sun and a flare occurring would affect the vicinity of the Earth, trying to predict how much time would you have. And that was worked in to the contingency plans. Based on what part of the mission the event occurred, you would then move to get as much mass between you and that event as possible.
And ultimately meant you'd get into the command module as fast as you could, because that would have the most mass. And so if we were on the surface, we would try to get off the surface as soon as we possibly could and rendezvous with the command module.
AUDIENCE: How much warning did you feel you had with--
SCHMITT: There is still some debate over that. At the time, it was felt that it was about an hour. Although some people who still study that problem suggest that it may be only about 30 minutes. And I can't tell you why there's that factor of two discrepancy. They've not been able to explain it to me, and I can't explain it to you. But there is that kind of a debate going on about it. But it's not much now.
The only one I know now, there probably was a very easy solution to the lunar surface flare problem, and that is to use a linear-shaped charge, explosive charge, to create a trench, drive the lunar Rover over it, and have some capability to at least pile dirt, pile regolith, on top of that Rover. That would be a very good way to deal with the mass issue, and just live off-- by cutting down the rate at which you're working, you could live off your consumables for a number of hours longer under that Rover than you would of if you were working.
Now, you could augment that solution by having some additional consumables on the Rover that you then could attach to, with a vacuum transfer, into your suit. All of those things are feasible. And as a matter of fact, as we look towards lunar bases, I personally think that's probably the way you'll deal with that continued hazard and the risk associated with it, is to have those kinds of systems worked out in advance. So I don't think in the long run it needs to be a major issue for, actually, permanent activities on the Moon.
I'll take your question and then I'll have a closing one.
AUDIENCE: What are your thoughts about the issues of manned versus unmanned in lunar and planetary missions? I know the American Astronomical Society-- members of the American Astronomical Society are very much in favor of the unmanned missions, that they are much more cost effective.
SCHMITT: Well, I'm in favor of both of them. I just was a principal investigator on a proposal for the Discovery Program to put a lunar Rover, a new Rover, automated Rover, on the surface of the Moon to get a better three-dimensional understanding of the lunar regolith, scientific understanding of the regolith, not only for science in many different ways, but also to better understand how to design future habitats, machines, and things like that, that would operate on and within the regolith.
So I feel very strongly that you need to find the right balance. But at some point, you'll always find me feeling very strongly that the integration of robotic or automated technology and the human capabilities is ultimately the way to get the greatest return on the buck spent. It's partly my nature. I hope it's partly a good logical position to be in. I just don't see how we can fully scientifically or humanistically take advantage of the opportunities that are available to us in space without the combination, and particularly, without the presence of human beings at some point in that pyramid.
The argument will go on. I have heard people, including my good friend Carl Sagan, say that everything we learned on Apollo could have been learned with an automated system. I'll give him that, but he's never had to cost that out. And I just have a strong gut feeling as an Earth scientist that to get that level of understanding of the history of a small planet purely through automated missions would have cost you at least as much in then year dollars as the Apollo program cost. And I'm not sure it would have been possible with the technologies that were available then.
Now we have a somewhat different picture. What you can gain with some of the advanced imaging and analytical mass spectrometry, particularly technologies that we could put on a Rover, automated Rover on the Moon, is far and above what we could have done 25 years ago. But still, I think the argument's a useful one because it makes everybody think. But the other side, shall I say, if I'm on the man side, has never really had to cost out all of these things that a human being can do when they're left-- a trained and experienced human being can do when they're put into their own environment in space.
MODERATOR: You asked the closing question I was going to ask. So with that, I will thank Jack Schmitt for a lecture that we'll remember perhaps until we see the next man on the Moon. Thank you.