Apollo 16: At ‘House Rock’

April 23, 1972: This TV view shows the the small figures of John Young and Charlie Duke just to the right of House Rock, which they examined on their final Apollo 16 moonwalk.


It’s another day, April 23, 1972, out last one on the surface, and our third and final moonwalk.  Of course with the delay of nearly 6 hrs. in landing three days ago, we’re lucky to have a third walk.  It’s been cut to 5 hrs., because in not much more than 4 hrs. after we end it, we have to take off.

We’re going to North Ray Crater, more than 4 mi. away, the farthest away we’ll travel during our exploration and the prime planned objective of this EVA.  It’s the largest crater to be visited in the entire Apollo program.  It’s 3,00 ft. in diameter and 650 ft. deep, too deep and steep to go to the bottom, but we’ll sample on an arc along its rim, hoping to find boulders excavated from deep below the surface of the Cayley formation.

It’s a shame, though, what we’ll lose.  Can’t help thinking of it.  On the way back in, we were going to stop at a crater in the flank of Smoky Mountain to the west of North Ray and sample Descartes material.  Then we were to sample the rim of a large Crater, Palmetto.   Those stops have been eliminated.  We’ll only make one short stop on the way in from North Ray. 

  We want to get ahead, as an early start means more time for the moonwalk.  We complete our preparations to get outside a half hour early — which will yield more time to explore.  We climb down the ladder for the last time at 10:25 a.m. EST on Earth.  Our capcom, Tony England calls, “Out again on that sunny Descartes plains.”

I answer, “Ain’t any ‘plains’ around here, Tony.”  It’s all craters and rocks and rolling ridges.

Gathering up all we’ll need and preparing our trusty Rover takes time.  Finally 38 min. after stepping out you tell Houston, “We’re all set to go.  And off we go.”  We look for landmarks to guide us, as a ridge is blocking our view to the north.

In just a minute we top a ridge, boulders about 1.5-ft. tall poking out of the dust here and there, and can see the low bulk of Smoky Mountain in the distance.   A minute later, I say, “I think the boulder population is starting to thin, Charlie.”

We come down off the ridge into a valley below, into rolling terrain  

“Looks like we could be out of this ray.”   The amount of small rocks — we call them “cobbles” — is decreasing.  Our plan is to at least drive up on the rim of Palmetto and take a look.  We reach it 10 min. after departing, driving an arc just inside the rim.  You scout the crater as I have to concentrating on driving.  “Palmetto has a very definite raised rim to it, and we’re going to be going off the rim down probably a 5 – to 10-degree slope into a valley before we start climbing up to North Ray.”

I zip down off that rim as fast as I dare — beyond it, some boulders.  But the small rocks have all but disappeared.  We’re looking ahead to North Ray.  “Look at those rocks!  Tony, there are some tremendous boulders on North Ray, and they get bigger as we go nearer.”

And we’re only 18 min. into our drive, about half way there.  

The terrain is rolling, the surface becomes smoother.  I throw the throttle full speed.   It’s some fast ride, juking around boulders and small craters.  “Uh-oh.  Oh, man,” you exclaim as we miss one.

About 26 min. into the ride, we reach the slope leading up to the crater.  No rocks straight ahead.  “All right, let’s go,” you say.”  Just about straight up — passing by two big frothy-looking boulders.

A couple minutes later, I say, “OK, we’re going up a pretty steep slope, right now, Houston. . . . I think we’re almost at the rim.”  But distances are so deceiving on the moon.  I’ll swear we’re about 65 ft. from the rim.

Houston, plotting our navigation, says, no — we’re still more than 1,000 ft. from it.  You concede, “Well, you might be right.”

We climb what we thought was the rim — it’s just another ridge, “one of these little hummocks,” I tell Houston.

“Little hummocks!” you say, “It was a pretty steep hummock.”

And just a minute later:  “The rim is right there.”

“Right on the rim, Charlie!”  We can’t see into the crater, but we see some big blocks.  “The biggest one, Tony, is this 10 – to 15 – meter boulder that is on the rim, and it’s blackish.”  

Believe me, you’ll be hearing a lot more about this black boulder.  

“We’re definitely on the ejecta blanket.”  We’ve parked about 300 ft.from the rim.  We’ve arrived 35 min. after driving off.

You say, “I can’t believe the size of that big black rock over here.”  That’s the one.

Tony radios that we’re about 17 min. ahead of the timeline which means more time here.  Nothin’ like a little fast driving!


I walk toward the rim.  What a giant hole, plowed deep into the surface, rocks and boulders flung everywhere.  “Man, does this thing have steep walls.  Now, I tell you, I can’t see to the bottom of it, and I’m just as close to the edge as I’m going to get.  That’s the truth.”

The inner rim is actually two.  I’m standing on the upper part, which has about a 15-degree slope.  Another 100 yards down, an inner rim suddenly drops, about a 30 degree slope.

You observe, “I see no bedrock . . .  All I see is boulders around the crater . . . just loose boulders.”  The boulders do seem to follow in two horizontal layers, covered in debris.

We’ve been here 5 min. and begin sampling.  I get me a piece of one.  “This is definitely a breccia right here, a big foot-and-a-half breccia.  It’s a white matrix with dark clasts, and it looks to be a three-rock breccia.”  Breccia — impact rocks formed of fused pieces of older rocks.  Clasts are the bits mixed in them, like raisins in a muffin.  And we’d hoped to find igneous volcanic rocks.

Tony calls, “And John, we’d like you to start ranging out in the best traverse direction for about 80 meters, if you can go out that far.  And survey the areas as you go out, and Charlie will follow you along, and then sample as you come back.”

You’re taking a series of photos of the crater, and report, “Sixty percent of it is covered with boulders.  The boulders are splayed out in a ray. . .  Can’t see the bottom.” 

The idea is sample 260-ft, arc along the upper rim, starting to the south and moving northeast where that black rock sits below almost at the steeper inner slope.

I head out.  “Did I drop my bags, Charlie?”   Meaning my plastic sample bags.

“Yeah, you dropped your bags.”  That’s a hint of problems ahead.  We carry the bags and large cloth sample containers attached to the sides of our backpacks.  Increasingly, they’re just not keeping attached.  I go back, dip low, bending at the knee and try to scoop it.  And fall.  We’re becoming experts at falling!

You range ahead.  “That’s about 80 meters, John.  Man, are we dusty.”  We’ve been here 17 min. now, and were scheduled, before any time extensions, to stay about an hour.

We’re going to sample independently, usually a two-person job.  I get at it.  “OK, Houston.  I’m going to pick up a sample which I think is the black-type rock, but it’s sort of dust covered.  . . . Oh, by — well, I was wrong.  It was a . . . white rock with a lot of black clasts.”  It looks like its taken quite a beating.  “And that’s going into bag number 383.”  We carefully describe each sample and note which bag it goes into.  

“God damn it.”  My bag dispenser has come off again.  I have to bend low at the knees and snatch it up.

“Boy, it is hot out here today.”  The sun angle, 15 degrees above the horizon when we landed, had risen to 55 degrees.  Those long shadows at landing and during our first EVA are now very short.  

Now 27 min. into the stop.  “I’d like to make sure we aren’t overlooking something here, Charlie.”

“That’s why I’d like to go down to that black rock down there, John.”

“Yeah.  You’ve really got your eye on it, I can tell.”

Tony says he wants us to sample boulders from here on.

You go away from me, to the southwest to some large white boulders, saying you’d like to try your hand at them. 

Tony asks me, “John, how far away is that big boulder?”  He means the big black one.

“It’s about, near as I can tell, 150 meters . . .”

Actually it will turn out to me much further, 220 meters.  That’s about 720 ft. away.

Meanwhile, I’ve had it with these bag dispensers.  “Charlie, I think with these equipment problems.  We’d better work together, and I’ll handle one bag, and you handle the other bag, and be able to be more productive.”  We’ve already spent 37 min. here.

“Yeah, I guess you’r right.” 

We sample the large white loaf- shaped boulders along the upper rim in a line.  Tony says, “If possible, we’d like to sample the stuff on top of the boulder.”

“That’s what I’m going to do.”

I’ve brought the rake along.  We use it to sift the soil for small pebbles.  “We’re sinking in these slopes 6 in. or so.” 

You, ask Tony, “How’s the time doing?”

“You’ve got an extension here, and you’ve got about 25 min.”

I say, “Let’s head out for the big rock.”

Tony says, “We think that sounds like a great plan.”  Houston is eager to have us sample it, too.

I say, “It may be further away than we think.”

You protest, “No!  It’s not far.  It’s just beyond you!”   You don’t want Houston to tell us it’s too far away.

Off we go.  “Ah, the old footprints on the crater rim!”


We lope on down and down and down.  And the big rock seems to grow.  “Look at the size of that rock!”

“Look at the shape of that rascal!”  

It’s a huge mound, a rounded peak off-center to the left, and over to the right, sloping down to a smaller section, a split there — actually two rocks.  It rises straight out of the dirt — no jumble of debris around it.  

You say, “Well, Tony, that’s your House Rock, right there.”  And the name sticks.  It is as big as a house. It is 65 ft. long and nearly 40 ft. tall.  And it’s close to the steep inner rim.  As we shift around it, watch your step!  “Charlie, don’t get too near the edge of that thing.”

We only have 17 min. to work here.  It’s a breccia, black with lighter clasts of igneous rock.  That’s as close as we’re gonna come to volcanic rock.  We chip out samples, and scoop some shaded soil from the split between the two rocks.  It’s now 1 hr. 46 min. since we drove off from the LM.  We’ve been at this site 1 hr. 11 min.   Time is running out, a shame.

We sample the soil in front of it.  Tony calls, “You’re going to have to leave after that.”

I pick up one last rock and head up.  You take one last photo of that magnificent house and follow.  In less than 3 min., we’re back at the Rover.

We drive off after 1 hr. 25 min. exploring North Crater, headed for what we’re calling Station 13, our last sampling site except for the area near our LM, Orion.  Tony tells us to follow our tracks.  “Station 13 will be down your tracks in the midst of the big boulders you described on the way up.”  We’ll just have time to sample one of the boulders.

Driving downslope is smooth going, speedy.  You’re enjoying the wild ride, laughing “This is going to be something going down this hill.”  A few minutes later, laughing again, “We almost spun out on that one, babe.  That was great!”  

“We just set a new world speed record, Houston, 17 kilometers per hour on the moon!” I say.  That’s 11 mph.

Houston is more cautious.  “Let’s not set anymore.”
A bit later, wham!  The right wheels dive into a crater, tilting us.  I give a hard correction, and the rear end breaks loose.  We spin 180 degrees!  Oh, man — we were close to tipping over.  I’m not saying a word.


In just 8 min. we come to the boulders, taller than we are, and I pick out one.  “See that big rock over there?  Maybe that’s a permanently shadowed one.”   It’s a lumpy thing with a big piece sticking out at an angle — deeply shadowed.  And Houston would like a sample of dirt that has escaped exposure from the sun, frozen in time, so to speak.  Hence, the rock becomes forever known as Shadow Rock.  

You tell them, “We’re on about a 5-degree slope away from North Ray . . .  The rock types here appear to be the same as we sampled up on top . . .”

While you sample the boulder, I’ll reel out the Lunar Portable Magnetometer and take magnetic field readings.

You head to Shadow Rock, saying, “I can’t believe I’m going up into that beauty.”  And “into” is the word.  Under the overhang, in the deep shadow, you push yourself down on your hands and knees and reach as deep into the crease under the rock with your shovel as you can.  And pull out dirt.  “I don’t know how long that rock’s been there, but that dirt has been shadowed ever since it’s been there.  John, you couldn’t have picked a better rock!”

When I see it, you joke, “Do that in west Texas and you get a rattlesnake.  Here you get permanently shadowed soil.”

Chipping some samples on the sunlit side, somehow you fall and wedge yourself against the big rock.  “Oh, rats.  John, I’m trapped . . . Can’t get up.  . . . Give me a hand.”  

“What do you mean?”

“I’m against this rock, ” you laugh.  I amble over and help.  

You report, “OK, Tony I got three chips off the rock.”

“We’d like you to go back and start loading up.”

Ah, Tony.  We leave after 29 min. at site.


We cross over that first ridge, and there it is, Orion.  You exclaim, “Home again, home again, jiggety jig!”

I haven’t quite become a cautious driver.  We do 14 kph down the ridge.

You comment, “Boy, not having that fender really sprays the dirt.”  Our spacesuits are turning gray.  We’ve driven for a half hour since Shadow Rock.

Well, we’re not quite done.  We stop near the ALSEP site to take a few last samples, still looking for igneous rocks, and to hammer in one more core tube.  We spend a half hour there, then I drive to LM — time to offload everything and pack up.  You’ve already dashed to Orion on foot, around it to the crater we barely missed on landing, getting a few last samples.  Tony tells us, “We’ve got about 10 more minutes of sampling, so why don’t you just pick up what looks interesting to you there.”  We’re working the geology to the very end.

Time up, you report, “And, Tony, the last one I picked up is an igneous rock, no breccia.  . . .I’m not kidding!”

It takes time to back everything up, not just samples, but all our camera magazines, making sure not to leave any behind.  We take in a couple passive experiments that we set up near the LM, capturing cosmic rays and particles of the solar wind.  And our astronomy experiment, the Far Ultraviolet Camera, clicks away to the very end when, last of all, I remove its film cassette.

We’d planned a little fun at the end of our last moonwalk, something we called the Lunar Olympics.  But with the EVA shortened we don’t have time.  Still, before positioning the rover where it will watch our liftoff, I give a little demonstration of the high jump.  Holding the Rover, I give a little leap.  Then a little high, letting go.  And again.  And then a bigger leap, in the air 2-3 ft. for a couple seconds! 

Charlie tries it, but starts with a big leap.  In midair, starts to rotate backwards, yells, “Wow!”  And hits on his back, right on his backpack.   

“Charlie!”  He coulda busted his life-support system.  “That ain’t’ very smart.”

“Well, I’m sorry about that.”

It’s coming to the end.  We dust each other off as best we can, make sure we’ve got everything.  And after 44 min. closing things up, we’re done.

Charlie reports “OK, John is in, Tony,”  We quickly begin to repressurize the cabin.  As we do, Tony calls, “You’ve had a 5 hr. 40 min. EVA.  And the backroom sends a great big ‘outstanding.'”

Despite the delay in landing, we’ve set all sorts of records.  We’ve collected 213 lbs. of samples, compared to 170 lbs. for Apollo 15.  We’ll have spent 71 hrs. on the lunar surface, four more than they did.  And we’ll have explored the surface for 20 hrs. 15 min. total, compared to 18 hrs. 35 min. for Apollo 15.

And now we’re 4 hr. 20 min. from lunar liftoff.


As we prepare for liftoff, we ask how our supplies are holding out.

Houston says we’re in great shape; we’ve got 18 hrs. of power and 10 hrs. of coolant water.  They joke, “Would you like to do a fourth EVA?”

“If you let me sleep, I wouldn’t mind,” you say.

No, it’s time to go, 8:25 p.m., EST.  `”Orion, you are go for liftoff.”

Ignition.  Liftoff, 175 hrs. 43 min. 35 sec. into the mission.  Bang!  We feel a rumble in our feet.  We rise quickly, and just 800 ft. up, Orion pitches over, as planned, on profile.  We’re looking down and gain a brief glimpse of the descent stage left behind.  And the Rover.  And our tracks, all those tracks.

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