July 31: Apollo 15 takes the first ride on the moon

Fifty years ago: The Rover near Hadley rille.


            With our spacesuits off and hammocks strung crisscross in the Falcon’s cabin, what a good night sleep we have on the moon at the plains of Hadley.  That is, until Houston wakes us an hour early.  They’ve been monitoring a slow oxygen leak.  We quickly trace it to something else new on this flight, a urine disposal system piping the waste overboard — instead of, as on earlier flights, carrying that weight back into orbit.  

            Oops — we left the dump valve open.  Sorry about that — but, damn, you should have woken us as soon as they detected the leak. Of our supply of 39 lbs. of oxygen, nine have leaked away.  That will only leave a margin of 2 lbs. by the time we finish with Falconon August 2.

            Well, at least we make an early start for our first moonwalk, scheduled to last seven hours . Our first task will be to unveil the “LRV,” the Lunar Roving Vehicle.  It’s folded like an intricate flower in one of the front quadrants descent stage of the Lunar Module, to right of the ladder as you go down. Weighing 455 lbs. on earth which equates to 76 lbs. on the moon, it can carry 1,064 lb., Earth weight, including two astronauts.  Unfolded, it chassis is 10 ft. long, 6 ft. wide, with a wheel base of 7.5 ft.  With front and rear independent steering, it can turn within its own length. It’s wheels are made of woven piano wire with chevron tread plates attached.  Each wheel is driven by its own quarter-horsepower electric motor.  Two 36-volt batteries provide power.  The two seats look like lawn chairs, with room behind for a tool/sample carrier.  A “T” handle serves as controller, speed and direction.  A center console displays the vehicles status, speed and distance traveled.  A gyro-compass, calibrated with a simple sundial and our landing spot, will let us know exactly where we are and will display the shortest route back to Falcon.

            With the Rover, we will be able to sample several different types of lunar geology.  With out it, we won’t achieve our primary goal — the mountain front, where the ancient mare washes up against Hadley-Delta mountain.  We want to explore this area, riding 200-300 ft. up onto the mountain, searching for rocks that predate the time when the Imbrium basin filled with the lava, perhaps finding pieces of the original lunar crust.   We’ve landed on the frozen lava of the mare, will sample it, too, for comparison with previous mare landing sites   We will explore the rille, which meanders from the mountains for 62 miles before merging in the north with another rille.  Are they collapsed lava tubes, as scientists believe? Or were they formed by surface rivers of lava?    And on our final moonwalk, hope to reach the North Complex of craters on a hummocky rise which appears to have formed by volcanic processes.  There, we may find the youngest lunar rocks.          

            It’s time.  We open the hatch.  “It’s blowing ice crystals out the front hatch.  It’s beautiful.”

            We switch on the TV camera to record our first steps.  It’s a new camera of much higher resolution built by RCA.  In addition, it’ll come with us, attached to the Rover, operated from Earth, able to pan, tilt and zoom.  Three minutes later we step on the moon, 9:29 a.m. EDT.  

            Give us a quote: “As I stand out here in the wonders of the unknown at Hadley, I sort of realize there’s a fundamental truth to our nature — man must explore.  And this is exploration at our greatest.”

            Wow — we immediately see why Falconis at a tilt.  “We’re on a slope of probably 10 degrees . . . and the left rear footpad is about 2 ft. lower than the right rear footpad.”  We’ve landed smack on the rim of a wide, shallow crater, the engine bell digging into the rim rise, buckling.  Indeed, Falconis resting more on the engine bell than on the front footpad, which is damn near off the ground.  “But the LM looks likes it’s in good shape.  The Rover is in good shape.”

            We quickly adapt to moving on the moon, prepare the “MESA” work table at the side of the LM.  “”OK, let’s take a look at our Rover friend here.”

            The Rover his folded with the bottom of the center section of the chassis facing out, shielding the workings, the end chassis sections with wheels folded in.  The deployment is semi-automatic, but has experienced a troubled history of development, with many late changes.  We can’t be certain we can even deploy the thing.

            At close inspection, we see the hinges of the deployment supports have popped open.  Luckily we are able to reset them.


            “Here we go.” The top drops like a draw bridge. 

            From Falcon‘s porch, we pull a lanyard and release the top of the chassis  Pull on a tape-like cables and the rear wheels pop into place.

            “She’s coming down OK.”

            “Easy.  Just pull real easy.”  We slide the the rover outward, still hanging above the ground, supported underneath bya deployment brace we call “the saddle.”   The front wheels pop open.  We have a problem — the saddle.  “It’s still seems to be connected to the frame of the LRV.”

            Capcom Joe Allen replies, “Roger — we copy, and we’re working on it.”

            In a flash they Joe says, “Pull the Rover as far out from the LM as you can, then . . . lift up on the front end.”

            We do so, and our piano-wire wheels touch down.  “Good show.”

            We extend the seat backs, the center console, and she’s ready.  Before taking the time to load up with geology equipment, we’ll take a short test drive.  Just to make sure the thing works.   

            “I’ll see if I can hop in.”  It takes an awkward side jump in our stiff pressure suits.  “You sit up a lot higher than in one-G.  That makes sense.”

            “Buckle your safety belt,” Joe calls.  Easier said than done — the buckles are poorly designed — indeed will be redesigned for Apollo 16.

            OK, read out the systems status, voltages and temperatures, like a preflight checkout in an airplane.  It’s time to roll.  “Out of detent. We’re moving.”

            “I don’t have any front steering.”  The Rover can maneuver with just rear steering.  No problem but . . .  Will Houston have one of their fits of caution where they insist on the redundancy of both front and rear steering?  Will they restrict our use of the Rover, eliminate long drives?

            Joe calls up, “Press on.”

            Yes, press on — full bore.  Load her up for our first traverse, which we will do before deploying the Apollo Lunar Surface Experiment Package (ALSEP).  We need to make our geology run first — to the furthest point in our traverse, three miles.  That’s due to the “walk back constraint.”  You don’t want to drive further than you can walk home should the Rover break down.  As that distance is determined by our oxygen supply, it keep shrinking at the day goes on. So head for the furthest point and work back toward the safety of the LM.  

            Nearly two hours into the moonwalk, running 25 min. behind schedule, we drive away, mark it as 11:20 a.m. EDT.  It should be a 17 min. drive to Elbow Crater at the point Hadley Rille swings to the west. “Go straight toward St. George Crater,” Capcom Joe Allen says, and that should bring us to Elbow.  And Rhysling Crater should be a good landmark along the way.

            OK, we’re moving forward, Joe.

            Whew! — hang on. Full throttle, we are, making 8 – 10 clicks, which is about 6 mph.  But seems a hell of a lot faster.  Boy, look at that — an elongated depression.  We’re gonna have to do some fancy maneuvering here.  Look at these craters.  Hang on!  We bounce through the small ones.   Good o’l Rover.  “It negotiates small craters quite well, although there’s a lot of roll.”    

            Gotta maneuver around the larger ones.  Whoa — the rear end breaks loose, fishtails.

            Whoa.  Hang on.

            Large subdued crater at one o’clock.

            Whoa.  Hang on.

            A bucking bronco.

            Yeah, man.

            “Can’t see the rille from here.  Still looking for Rhysling.”  We dip and bound, bounce and swerve.  “Man, this is really a rocking-rolling ride, isn’t it?”

            “Never been on a ride like this before.”  Ha — a boat on choppy seas.  Seas of lunar dust pelted with rocks and craters.  

            Where’s Rhysling? The nav. system says we’re still well short of Rhysling.  Distances sure are confusing.

            We crest a ridge and . . . “Hey, you can see the rille!  There’s the rille.”  Can look across it to craters on the other side.

            “Yes, sir. We’re on the edge of the rille, I bet you.”   We’ve gone west of the planned route, smack to the edge of the rille.  We don’t know it, but because Houston misjudged our landing point, our nav. system is set wrong.

            “I don’t see Elbow . . .”

            We spot a crater, not as prominent as we’d envisioned.  Subdued — but it must be Elbow, still a ways away.

            “Hey, look there’s a big block on the edge of the rille there.”  It must be 30 ft. across. Lots of outcrops.  We’ve actually strayed over the levee-like ridge at the edge of the rille.  We’ve dipped along its shallow slope.  “Let me get us back up on the ridge; it’s smoother.”

            “Yeah, there’s a definite ridge or rim that runs along the rille.”

            We head for the east side of Elbow Crater.  “We’re in good shape.  We can see Elbow and the mountain front — “There’s not a big block on it.”

            “I see one large block, about a quarter of the way up the Front.”  Maybe we can sample it.  “Oh, there’s some beautiful geology out here!”

            We’ve been driving 17 min., still have about a half mile to go.  It almost looks like we could drive right to the bottom of the rille, which is flat, not V-shaped.

            “I’m sure we could drive down; I don’t think we could drive back out.”

            “You want to go a little farther east.  See, that’s Elbow out at 11:30.”

            “Oh, yeah, rog. Gosh, that’s a long way away.  Distances are deceiving.  Like we’ve been driving for an hour. ” Actually, we’ve been driving for 24 minutes.

            “Are you sure that’s Elbow?”

            “Yeah, yeah, you want to go farther east.”

            “Look at this baby climb a hill.”  We reach the east flank of Elbow, 26 minutes after departing Hadley Base.  “We’re on the high point, east of Elbow,” on the opposite side of the crater from the rille.  “A quick sample here, then just press on.”  Running about a half hour behind, we only spend 12 min. here at “Station 1,” 

            “I wish we could sit down and play with the rocks.  They’re shiny, sparkly!”

            But we press on, higher up, beyond the crater, up the slopes of the mountain front — toward but not to St. George Crater.  And 12 min. later, we stop, “Station 2.”

            Whew! — we are on a slope.   Looking back down the valley, three miles from Falcon.  Looking down into the rille.  And if we turn, looking across to the bulk of Hadley Mountain shrouded in shadow to the right, peering up from the short horizon, the vista dressed with rolling hills.  “This is unreal.  The most beautiful thing I’ve ever seen.” 

            We’ve stopped at the one boulder we’ve spotted, about knee high.  Dirt — which we call “fillet” is bunched against the downslope slide.  Which is a mystery — usually dirt piles up on the upslope side.

            “I can see underneath the upslope side.”   We first sample the fillet dirt.  Then take a sample of the dirt away from it for comparison.  And the shadowed dirt under the upslope side.  And of course chip off samples from the boulder itself. “Let’s try the old hammer.” “Ugh — that is hard.” And it’s hard working on a steep slope, slide-slipping along like skiers traversing a hill.   We managed to knock a couple chips from the top of the boulder. 

            We observe that it looks young, in lunar terms.  Our capcom, Joe Allen, comments, it is — “And it probably isfresh. Probably not more than three-and-a-half billion years old.”

            “Imagine that — it’s been here since before creatures roamed the sea.”  And after all those billions of years, we roll it over.  “Get a scoop of that underneath” — soil shielded by the rock for billions of years.

            “That’s just an unreal rock.”  And we have other work at this site — a rake sample, more of a sieve than a rake that gathers small rock fragment representative of the area.  And we hammer in a core tube, with only 10-15 min. before we must leave.  

            We’ve expended 52 min. at this site.  We’re less than four hours into the moonwalk.  And Houston gives us some unwelcomed news — one of us out here is using oxygen a wee bit faster than anticipated.  We’ll have to cut the walk a half hour short, to about 6.5 hrs.

            We’re going to skip Station 3 and go directly back to the LM, move on to today’s second act — setting up the ALSEP science station.  Joe Allen tells us to use our nav. system, keyed with a direct route back to the LM, to go straight back, east of the curve path we took outbound along the rille.

            It’s downhill most of the way, but we have to watch the speed.  Coming over a rise, here’s a crater.  Steer hard to avoid it, locking up the front wheels. The Rover does a “180” spinning around so we’re facing uphill.  We laugh, but you know — we could flip over in this thing.  

            Reaching the mare plain, we find it studded with small rocks and . . .   One stands out, sitting by itself, a beautiful volcanic basalt. Gotta grab it.  But Houston would never OK a stop at this point.   We make a ruse — that we need to adjust our seatbelts. “We’re stopping.”  Don’t say a word.  This sample will become famous as “the seatbelt basalt.”

            Quickly on our way again and . . .  “There are some Rover tracks.  How about that!”

            We’re back.  The ride takes 33 min.

            Now, in a sight familiar from past Apollos, we unload the ALSEP, contained in two boxy packages carried barbell style on a pole to a flat area about 350 ft. from the LM.  And we drive the Rover to the site, one experiment resting on one seat — a Laser Retroreflector and something that will become our nemesis — a battery-powered drill for making deep cores. 

            Everything goes smoothly, setting up seven experiments, most connected by ribbon-like cables to the central station.  Remove a packing of insulation and dust covers.   Place them radially around the central station, like a miniature city. There’s a seismometer to detect moonquakes, and with ours the completion of a network of three with those of Apollo 12 and 14, allowing triangulation of the exact depth/location of the sources. There’s an magnetometer, three booms extended to detect the moon’s weak magnetic field.  There’s a Solar Wind Spectrometer which will measure the denisity, direction and variation in the protons and electrons streaming from the sun. There are two packages, the Cold Cathode Ion Gauge and Suprathermal Ion Detector which will also measure the stream of charged particles in the solar wind and also in the moon’s tenuous atmosphere. Attached to the central station, a Lunar Dust Detector will measure the amount of dust that accumulates on a solar cell.  Separately, the Laser Retroreflector, like two placed previously on the moon, will be used to bounce back laser beams from earth, allowing very precise measurements of the distance between the two, within inches. 

            And then comes the heat flow experiment, designed to measure the heat flowing from the moon’s core. We plan to drill two holes to a depth of about 10 ft. and place sensitive thermometer sensors in each.  

            “OK, Joe, I’m picking up the drill.”   We attach a section of core tube and get to work.  At first it goes in easily.  Then not. “It takes a little bit of force . . .  It fact it’s getting a lot stiffer. . .  It’s tough down there.”  We’re straining over it, pushing hard.  “Whew.”  Is that as far as it’ll go? — only about 5 ft.  Give it one more try.   Damn. “I’m afraid that’s it.”

            We have trouble removing the drill.  “It’s locked up in there.”  We can detach it from the drill stem.

            Take a breather, Houston advises, while they think it over.  They suggest using a wrench-like vice from the Rover, used to unscrew segments of core tubes.  

            Sure enough. “It worked!”

            We insert the heat probe into the hole.  And begin drilling the second hole.  This drilling operation is working the hands hard — not easy to manipulate the equipment in the pressurized gloves.  Our fingernails are pressing painfully into the glove tips.  We pay no mind.  We only have 15 min. more at the ALSEP site, begin drilling the second heat flow hole.

            “Whew — is that tough rock.  Same problem.”

            Stop there, Joe says, maybe you can drill it deeper later.  Later means on the next moonwalk, and that means taking time from other objectives.

            “We want you to move back toward the LM now.”  And start close-out activities, loading what we’ve gathered into the LM, as soon as we arrive.  Our first moonwalk ends, 3:49 p.m. EDT, after 6 hr. 34 min.  We’ve driven about 6 miles

            After we’re back inside, Joe tells us, “You’ve done a fine day’s work.  Why don’t you take the rest of the day off.”

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