Apollo 17, EVA #2: The orange soil

Fifty years ago, Dec. 12, 1972: The discovery of orange soil at Shorty crater

*****

It’s the December 12, 1972, 6:33 p.m. on the East Coast of the U.S. and on the moon, we — Gene Cernan and Jack Schmitt — aim to take Apollo’s longest stride, pushing the hardware and oxygen supplies to the limits.  We will make the longest drive in the program, our target the base of the 7,500-ft. tall South Massif, a huge loaf-shaped mountain that will loom over us during the moonwalk.  We’ll establish a sampling station at the edge of a depression, perhaps an elongated crater, we’ve named Nansen.  It’s a straight-line distance of about 4.5 mi. from our LM, Challenger, but to reach it we’ll have to drive a course of about 5.5 mi., which will take more than an hour.

As on all these EVAs (moonwalks), the driver really is oxygen.  Oxygen is time — and distance.  We must maintain enough oxygen that we could, if the Rover broke down, walk back to the LM.  Hence we sprint to the farthest point we want to explore, work there while our oxygen supplies are high, then work back towards the LM as that walk-back range decreases.

We’re starting 1 hr. 25 min. later than planned, as we’d been allowed to sleep in after a long debrief the evening before about our first moonwalk.  We’re rested, the ache in our arms gone, but today sure to be brutal on our hands fighting those pressure gloves.   We open the hatch and the pressure release sucks particles from the cabin. We hope it sweeps out some of the dust — oh, all that dust we tracked in, despite our best efforts to dust.  One of our first tasks will be to attempt to fashion a replacement fender extension for the one that broke off the Rover’s right rear wheel on our first walk.  Without it, the wheel tossed up cascades of dirt.  Overnight a team at Mission Control devised a make-shift replacement we can build from spare items, and John Young, suited up, constructed one to make sure it could be done.

“Okay. I’m going down the ladder,”  I call.

From the cabin, you say, “All of a sudden, all the noise is gone; that’s very good.”

“‘Godspeed the crew of Apollo 17.’ I think I’ll read that every time I come down the ladder.”

On the surface, I say, “Apollo 17 is ready to go to work.  . . .What a nice day.”

You add, “Not a cloud in the sky.  Except on Earth.”

*

“Let’s get this done.”

This is how to make a replacement moon fender:  We take four 8-by-10.5 in. laminated maps that we don’t need.  Using the gray duct tape we carry for all sorts of tasks, tape them together, working at the floorboard of the Rover as if it was a crafts table.  We create a 15-by 20 in. fender extension.  Then using two clamps designed to hold auxiliary lights in the cabin, attach the thing to the end of the remaining part of the fender.  Careful not to get dust on everything, or that tape won’t stick.  The clamps have to be screwed down tight — tiring “finger work.”  You can hear me grunt tightening those clamps down.  

The auto repair consumes less than 10 min.  “Well, that paper isn’t going to come off, and the clamp’s not going to come off, I’ll say that. I don’t know how much we’re going to get out of the fender but . . .”

*

You dash off on foot for the nearby Surface Electrical Properties (SEP) site for some checks of it’s antenna.  You observe the Rover as I drive out to the site.  “I don’t see anything coming up over the top.”  No rain of dirt.  “Looks like a good fix.”

After a few minutes there to set tracks we’ll use as guides for setting out the long antenna lines the end of the moonwalk, we head out, a straight-line dash at first, through what we call Tortilla Flats, headed for the mountain.

You make observations on the way, as I concentrate on driving.  And you’ll begin taking “rover samples,” something new you’ve devised — a kinda “Dixie cup” at the end of a long handle that allows you to scoop a quick sample without getting off the Rover.

Our route takes us past Camelot crater, 1,864-ft. in diameter, mantled with dark material — geologically young, we hope.  We want to see, as we pass, if there are boulders tossed up from the subfloor.  If so, we’ll want to sample them when we come back at the end of the EVA, still seeking young volcanic rocks.

“And I think we’re coming up closer to the rim of Camelot. It’s starting to look like a crater now,” you say.  

“Keep an eye out for blocks on the rim,” our Capcom, Bob Parker, reminds us.

It’s a very gradual climb for the Rover up toward the crater.  We’re averaging a speed of just above 6 mph.  That’s actually a good rate for the Rover.  Plenty fast when you’re trying to dodge sudden obstacles.

“Watch the crater. There you go.  I tell you, when Gene decides to turn. . .Whoo!”

“We’ve got the…Ooh, and there’s Camelot,” you exclaim.

Gotta say, “Man, are there blocks there.”   We spot the perfect place for a sampling station on our return.  “We won’t have any problem finding blocks on the rim,” you say.  West of Camelot, the number of blocks decreases greatly.

After a smooth stretch, (relatively!), we’re coming up on something. “Man, are there blocks there.  . . . “

“Okay. That must be Bronte,” you say.  That a crater, about the third of Camelot’s size, that not quite halfway to our destination.

“My God, is that big!”

You agree.  “That’s bigger than I expected.”

“Whoo! I got to go around this thing.”

Beyond Bronte, we drive onto the white mantle of the great South Massif landslide, yet there is no definite line, just a subtile change in color.

And  all this time we’ve been aiming for the scarp — a cliff that runs from the base of the mountain to the east.  Only it isn’t an actual cliff, but an undulating rise.  And we’re aiming for what we call “The Hole in the Wall” between lobes of the scarp, a gentle rise that should be an easy to climb in the Rover.   It’s out there in the distance drawing us to it. 

“We’re on the light mantle, no question,” I say.  The surface is becoming more hummocky.  Ahh, but I think the Rover could take more than we can dish out.  As we go along, you call out all the geological features we encounter, the shifting brightness (albedo) of the surface, the block and crater population, piecing together the picture of Taurus-Littrow.  “There certainly is a change in the general albedo, particularly in the craters. The craters are much brighter in their walls than we’ve seen before.”

“Looking up on the South Massif, we’ve got real good views of the block-strewn fields. There seems to be two dominant colorations of the rocks. The light-colored ones — very light tan to white — and then there are the blue-gray rocks. There’s one major outcrop of blue-gray about a sixth of the way down the slope . . .”

We’re still down on the plain, still going flat out at about 7 mph, and tell Capcom Bob Parker, “Got Hole-in-the-Wall, Bob. It’s a very long, very subtle, very gentle slope.”

Looking up at South Massif, I exclaim, “Boy, is that getting big. ”   We can feel the bulk of that mountain.  “Whoo-ee! . . . Hold on.”

We’ve got a long depression to go around . . .  “Okay, Jack, we got to watch it because I got to go around a long depression.”

We reach the scarp. ” I don’t even think the Rover knows it’s going uphill.”    Beyond, leading to the base of the mountain, some of the slopes become steep.  “I’m going to head more straight up the hill. Once I get up on top, I’ll be all right. I’m going to head down in this hole and then up that way . . .   I don’t mind pitch, but I sure don’t like roll.”  As in the feeling we could roll over!

“Jack, I’m going to head right along this ridge because I think that’s the depression we were talking about.”

“Yep, that’s Nansen down there.”  

We want to establish sample station 2 near the elongated crater, Nansen.  Still have more than half a mile to go.  “Let me tell you, this is quite a Rover ride.”

We head downhill into the edge of Nansen.  You observe, “But the trough is much greater in extent than just Nansen. It’s probably a kilometer wide. I never realized that it was so much of a depression in here.”  Looking up the mountain, you tell Bob Parker, “Bob, the boulder tracks are really just chains of small craters, for the most part.”

We find a good spot to sample boulder that have rolled down the mountain.  You tell Houston, “We’re right where we wanted to be for Station 2.  And it looks like a great place. Big blocks. It looks like quite a bit of variety from here. Different colors, anyway. Grays and lighter-colored tans.”

We’re at the base of the mountain, on level ground about 325 ft. from Nansen.  It’s been 70 minutes since we left the SEP site near the LM.  We’re at our prime sample site for the EVA.

*

 *** STATION 2 — SOUTH MASSIF ***

It isn’t as simple as leaping off the Rover and picking up rocks.  Rover systems have to be set; everything dusted off, camera magazines changed — on and on.   You’re eager to begin sampling at this important site and mutter, “Will we ever get started?”

`The real work begins when you describing the site in detail, forming a picture of the geology in your mind.  Boulders of all sizes are scattered about us, some half buried, some sitting on the surface.  We look for ones that have come down from high on the mountain.  “Jack, that rock has to have come down.”  

“No question about it.”

“Jack, let’s get a piece of this one right here.”  Those are what we’re after, as they could have either come from the early lunar crust before the impact that created the Sea of Serenity, or been lifted by the surge that created the mountains after the impact.

You inspect it.  “Oh, look at the blue!  Look at all the white fragments in it!”   And say, “We ought to sample across the layering” in the rock.  I get out my hammer and chip away. 

“How about this one? Here’s a whole big piece.”  We hammer at a bulging “clast,” a fragment locked in the greater matrix of the rock.  When we hit it — surprise — a big chunk comes off. 

“That’s a good representative sample,” you say.   

“It’s a football-sized fragment!” we laugh.

And then we scoop soil samples from around it.  And move on.  “We’re going after a lighter-colored boulder now,” you tell Houston.  “. . .This is crystalline.  There are fragments, I think.”

We move upslope and you gather a rake sample of representative pebbles, dragging the rake behind you with one hand.  As you rake, I move on and report, “OK, Bob, I’m at another boulder up the slope here. It looks quite similar to the one we just sampled, except there is a lot of flake fractures on it. Non-uniform, non-directional, but quite different, at least from that other rock, in terms of its fracture pattern.” 

I comment, “We have to be a million miles away from the LM.”   We can’t see it, as there are several intervening rises blocking our view.  We’re actually in a low spot, in the trough hugs the base of the mountain and includes Nansen.  Indeed, Nansen may be part of the trough and not a true crater.

We continue sampling across the slope, hopping to get up the steeper sections.  This is the perfect site to gather prime samples of South Massif, but we’re running out of time here — suddenly only 10 min. more.  Bob asks us if we want a 10 min. extension, time that will have to be taken from the stop later on at Shorty Crater.  It seems like a good idea.  “Let’s take it. ” 

As you scoop up dirt, you say, “I don’t know how we used up all the time, but we did.”

“I don’t know where the hour went that it took to drive here.”

“Maybe time’s different in space. Adventures in space and time!”

We move downslope and sample another boulder you picked out, one with a large intrusion.  I rapidly bunny hop down the slope.  “Man, that’s the way to come downhill.”

“Just don’t stub your toe.”   And beginning to work on the boulder, you say, “Let’s get that big clast.”

  Out comes the hammer.  “Yes sir!  That’s a prize.”

As we move on, you describe the fragment:  “That white clast. . .  I looked at it, and it has light, pastel-green, fairly-rounded crystals in a fine-grained white to light pinkish-tan matrix.  . . . It looks like olivine or something.”

And you know what?   One that fragments will turn out to be nearly pure olivine, hence the green color, the oldest rock found on the moon, 4.5 billion years old.  A prize, indeed!

We have time for one more boulder, a small loose one that wobbles when hit with the hammer.  A chip flies off.  “See it?”

Jack says, “See it!? You hit me with it!”

I kick the boulder.  It barely moves.  I kick it harder and it rolls a could times. We gather the soil that was underneath it which had been unexposed for eons.

Time rapidly running out.  One last rake sample.  You take one last scoop of dirt, a big one.  “One-scoop-Schmitt, they call me.” 

“We ought to start moving out of here.”

“Let’s go.”

Bob Parker calls as we load up, “Beautiful station, guys; just simply beautiful.”

*

*** STATION 3 — BALLET CRATER ***

We drive out of the trough, the view opening up.  “Look at that valley,” I say.

We’ll now start working back toward the LM to keep within the shrinking walk-back range imposed by our oxygen supplies.  We drive along the scarp, aiming to establish station 3 at its base near a crater we’ve named Lara.  “Bob, we’re on the top, coming off the highest lobe of the scarp looking back into the valley. And it’s quite a scene back there, but we still cannot see the LM.”

The scarp isn’t a straight line, but overlapping scallops of various sizes and heights.  You say, “See the lobes coming out . . . lobes coming out from the scarp.”

“Boy, that’s a sight, isn’t it?” 

We’re pitching down steep slopes.  “Okay, I’m going to try to make it down this. Hold on!”  I claim we must have set a new Rover speed record.  We gotta have hit 10 mph, I’ll swear!

Finally we’re off the scarp.  “Hey, will you look at the hill we came down! Same one we went up?

I’d rather not,” you say.

We loop across the route we took up.  Jack exclaims, “There are your tracks. Hey! We crossed somebody’s tracks!”

Bob jokes, “Hope they look like yours.”

As we drive, Bob tells us Station 3 will have to be a brief stop.  You report, “We can see a little bit down into Lara now.”

And we pick a small crater, about 100-ft. in diameter, near it as our worksite.  “We can sample the rim materials of this crater.  . . .There’s only about a half a centimeter of gray cover over very white material that forms the rim.” 

To save time, we work separately.  You take samples on your own.  “Okay, I’m going to start sampling the soils, and then I’ll get you the fragments.”  You dig a trench on the slope of the crater.  “There’s quite a marbling of light and dark material.”

At the same time, I use our trusty hammer to pound in core tubes, two core tubes, each 16.5 in. long that screw together.  “Well, the first core has gone down pretty good, Bob.”

I ask you, “How are you doing there?”

“It’s hard.”  It is hard without someone to open and hold the bags.  You fill a bag set on the ground.  The bag falls.  You get down and dirty on your knees to pick it up.  Moving on, you slide on the crater slope, fight to maintain balance, legs going out — you appear to be running after your legs in a crazy dance!

Bob, observing everything on TV, calls, “Hey, Gene, would you go over and help Twinkletoes, please?”

“Want some help, Jack?  I’ll be there.”

“No! I don’t need any help.”

Bob jokes,  “And be advised that the switchboard here at MSC [the Manned Spacecraft Center, Houston] has been lit up by calls from the Houston Ballet Foundation requesting your services for next season.”   And the crater henceforth and forever becomes known as “Ballet crater.”

We’re running up against the walk-back limits.  Bob calls, “Seventeen, we’d like to press on as soon as possible.”

You say, “We didn’t really do all the things we wanted to do, but I think we did everything we could.”   Yes, that’s always the case under the pressure of time.  “OK, Going to Shorty.”

It’s a 16-min. drive to Shorty crater, where we will only have a half hour before we hit those walk-back constraints again.

*

*** STATION 4:  SHORTY CRATER (the orange soil) ***

We drive up to the crater, and you toss out your first description:  “Shorty is . . . obviously darker rimmed, although the fragment population for most of the blanket does not seem too different than the light mantle. But inside…Whoo, whoo, whoo!”  The steep sides of the crater and its bottom is a cacophony of rocks, pebbles and dirt heaped in a central mound at the bottom. 

“You’ve got 25 min.,” Bob tells us, “. . .Our priority are samples from the crater rim.”

“We’ve got a boulder on the rim . . . It’s obviously crystal,” you observe, and while I dust off the Rover, go to it, below it. intending to start a photo pan of the crater.  It’s only a couple minutes into the stop.  Suddenly you yell excitedly, “Oh, hey.” 

You’d kicked up something in the dirt.  “Wait a minute,” you caution, not believing your eyes — lighting conditions have fooled us in the past.  No, this is real.  “There is orange soil!”

What? — I don’t believe it.  You must have gone space happy.  “Don’t move it until I see it.”

“It’s all over!  Orange!”

“Don’t move until I see it.”

“I stirred it up with my feet.”

Even before I reach you, I see it:  “Hey, it is!!!”

You repeat, “It’s orange!”  As if you still don’t believe it.

Either do I.  “Wait a minute, let me put my visor up.” — the gold sun visor.  “It’s still orange.”

“Sure is.  Crazy!”

“Orange!”

“I’ve got to dig a trench,” you say — which will reveal the extent of the orange soil.

Bob says, “Copy that.  I guess we’d better work fast.”  That’s because of those damn walk-back constraints.  We simply don’t have the option of taking extra time here.

You photograph the find, start digging the trench, dropping your scoop and going down on all fours to pick it up.

“That is orange, Jack.  Well, slap me with a little cold water . . .”

“I didn’t think there would be orange soil on the moon.”

We know what that implies.  You voice it:  “. . . It’s been oxidized.  It looks just like an oxidized desert soil . . .”  Oxidized, as in that it came from a volcanic vent; orange as in oxidized by water. 

You observe, “You know . . .that orange is along a line, Geno, along the rim crest.”

“You mean circumferential?” 

There’s a whole arc of orange soil paralleling that of the crater rim, just as a volcanic vent would produce.  Could Shorty be that vent?   “If there ever was a — I’m not going to say it — but if there ever was something that looked like a fumarole alteration, this is it.”   That’s your fancy way of saying the orange soil looks volcanic in origin.

You finish the trench.  “OK, Bob.  I’ve trenched across the trend of the yellow or the orange.  There is light gray material on either side.  Oh, man, this is incredible.”  After a pause for some photos, “OK, let’s start sampling the trench.”  

We sample down it and across it, bending deep knee as we scoop.  Scoop and bag, bend and scoop the orange soil and the gray soil at its side.  We want everything.  Ah, only if there was time.  We scoop fast, fighting the shrinking time, fighting the fatigue of the effort. 

“We’d like to get a double core,” Bob says.  

Bob says, “And the one problem at this station, Jack . . . It’s the fact that we’re running up against the walk-back constraints here in just a very few minutes, about 20 minutes.”  Just 20 min. left!

And damn if the core is hard to hammer in here.  you hold the tube steady as I hammer it down, breathing heavily.  Need a rest. “Wait a minute, Jack.”

“That’s all right, take it easy. I’d offer to hit it, but I don’t think I can, my hands are so tired.”

“Okay, let me hit some more. Ready?

We get the tube down as far as we can.  At least it pulls out easily.  Even the outside of the core tube is red!

We inspect the core ends as we separate the two tube sections, and you exclaim, “Look at that!”

“Even the core is red! The bottom one’s black and orange, and the top one’s gray and orange!”

“Hey, we must have gone through the red soil.”   

We still want to take a sample of the 6-ft.-tall, eroded basalt boulder that you were originally looked at.

Bob tells us, “And we’d like to get a quick sample of that basalt up there on the rim . . . and then press on.  And I emphasize that it’s walk-back constraint we’re up against in 14 min., 13 now.

And of that, we’ll need 3-4 min. to pack up and prepare for departure.

You work on two levels as once, sampling the boulder, and observing the details of the crater.  “If I ever saw a classic alteration halo around a volcanic crater, this is it.”  The mantle on the inside of the rim goes from gray to a very dark gray.  “And there’s a lot of orange stuff that goes now — radially down — into the pit of the crater.”

Bob says, “We need you guys rolling in 7 min.”

Let’s see if we can hack at another boulder, just one more sample.  But Bob says, “Guys, we don’t have that much time.”

“I got it!” you say — that one last sample.  “Let’s go.”

*

We leave Shorty, suspecting it could have fulfillment one of the primary quests of the Apollo program, the one Apollo 16 was sent to find and didn’t — a lunar volcano, a sign of geologically recent volcanic activity.  

But Shorty proves to be what we originally thought it was, an impact crater.  When the orange soil is analyzed, it’s found to be tiny glass beads, volcanic for sure — shot thousands of feet up by a fire fountain, splashing onto the surface and covered by a thin lava flow, then lifted by the impact that created Shorty.  The glass beads, 3.5 billion years old, yielded something as valuable as evident of geologically recent activity would have been.  They contain elements from deep within the lunar mantle, giving insight into the internal composition of the moon. 

And there’s more:  New analysis techniques of the 21st Century, showed that traces indicating water were locked in the beads.  

*

*** STATION 5 — CAMELOT CRATER ***

Our last stop of this far-ranging EVA is on the bridge-like gap between Camelot and Horatio craters.  During the 26-min. ride, we scoop up two “Rover sample” without dismounting and make a quick stop to deploy a seismic charge.  We establish the site on the edge of Camelot at a beautiful boulder field.  Field? — its more like a sea of boulders, waves of different sizes breaking from the rim of the crater.  You quickly ramble out amid the low boulders, inspecting them, while I’m consumed for 10 min. with mundane tasks, getting bags and camera magazines.  And yes, the endless dusting the Rover.

We’ve gotta work quickly.  “You’ve got 25 min.,” Bob tells us.

“I’ve got the impression these blocks are buried . . .” you report.  “The big ones seem to b projecting out of the mantle.”  You zero in on one to sample.

Coming over to you, I paddle over small boulders in leaps.  Here comes my hammer, hitting down on the top of the rock.  “Just a little piece.”  That’s all I can knock off.

You take the hammer, noting that we’ve already worn the rubber grip off the handle.  “Dr. Rock,” with long experience, knows just where it hit to knock off a sample in a single strike.

“Beautiful call!  Beautiful!” I exclaim

“That comes from 15 years as a hammer bearer.  You learn where to hit rocks.”

We go hopping through the dense boulder field, looking for a sample of dirt from the top of one of the boulders, hoping it’ll be a pristine sample from the mantle.  “It looks like it’s been thrown up from surface,” you observe, meaning it’s just the usual surface soil.   Still you swipe a sample with your scoop,

We were going to take a rake sample, but there’s no time.  Instead, Bob tells us to bag the soil between two boulders.   “We’d like you moving in 3 min.,” he says.

I move out into the boulder field for the photographs to document the site.  I’m out there when Bob says, “We’d like you to leave in 1 min.”

I run for the Rover in leaps, big bunny hops that lift both feet off the ground, singing “Hippety-hoppity, over hill and dale.”   

At the Rover, I say “My golly this time goes fast.”

Away we go, headed home, leaving the wonder sea of boulders to sit in silence beyond our grasp.

*

This day will be remembered as the high point of Apollo surface exploration.   We stretched it to the maximum, conducing a record moonwalk of 7 hr. 36 min. outside, traveled a record distance from the Lunar Module, covering more than 7 mi., collecting 136.7 lbs. of samples.  Unloading back at the LM, bag after bag carried from the Rover, I comment, “Man, I’ve got the sorest hands in the world right now.    

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