50 years ago: The last Apollo moonshot

Dec. 7, 1972: After a 2 hr. 40 min. delay, Apollo 17 is launch on the last mission to the moon at 12:33 a.m. EST.

***

The last will be the first — the last Apollo moon flight will be the first night launch of the 363-ft.-tall Saturn V.  That unique event is dictated by the need reach our landing site on the edge of the Sea of Serenity just after lunar dawn.  So launch is set for 9:53 p.m. (EST) today, December 6, 1972.  The Cape area is alive with anticipation of what our dragon of a rocket will look like, lighting up the area like the dawn of creation itself.

We move in glare and shadows from search lights all around and reach Swing Arm 9, the 320 ft. level, the crew access arm which ends in the tiny white room hugging the cone-shaped Command Module. We are the crew of Apollo 17, Mission Command Gene Cernan, in the left seat, Command Module Pilot Ron Evens in the middle, and Lunar Module Pilot — and geologist, Jack Schmitt, in the righthand seat.

Our destination, you and I, while Ron remains in lunar orbit, is a deep valley, about 6 mi. wide on the southeastern rim of Mare Serentatis, a site we’ve named Taurus-Littrow, for the Taurus mountains at the eastern edge of the “sea” and Littrow crater 20 mi. to the north.  We intend to explore the lower reaches of two mountains, or to use a geologic term, Massifs, block-like mountains formed by the uplift of lunar crust when the Sea of Serenity was created by a huge impact 3.8 billion years ago.  That shattered rock to a depth of 16 mi.  Our prime objective is South Massif, a loaf-shaped mountain rising about 7,500 ft. with what appears a huge bright landslide at its base.  And across the valley, we’ll explore the lower slopes of North Massif, about 6,500 ft. tall. and sample boulders, perhaps pieces of the original lunar crust, that have rolled from outcroppings near the summit.  The sides of these mountains are too steep, 20 to 30 degrees, for our Rover to climb, so in effect we hope to have the mountains come to us bringing some of the oldest rocks collected from the moon.

And we’ll also seek some of the youngest on the dark valley floor that appears to consist of volcanic ash.  Craters with dark halos were spotted in the area, possible volcanic vents, in orbital photography by Apollo 15.  Our site, not on the original list of possible landing sites, was selected on the basis of Apollo 15 observations.  We will be stretching the Apollo system to the maximum in multiple ways on this last chance to fill in the portrait of the moon.  We aim to spend 75 hours on the surface, a record, driving the farthest distance from the lander, nearly 5 mi., and drive the Rover a record 21 mi. during three moonwalks.

And to make all this possible, we’ll have to make a steep descent over the dome-like Sculptured Hills, which form the eastern side of what we like to imagine as a box canyon.  We’ll pass just 10,000 ft. over them (and later explore the dome-like hills on our third moonwalk).  If we have to abort, we’ll come close to what we’ve named Family mountain to the west.  You and I will make the landing in the lunar module we have named Challenger.

I’m in the left seat.  You’re in in the right seat — I call you “Dr. Rock” —  assigned to the crew in place of Joe Engle because NASA wanted to send a geologist to the moon.  You were one of the first scientist-astronauts chosen in 1965.  Ron Evans — I like to call him “Captain America” — is between us.  He will remain in orbit in the command ship, America, operating a suite of instruments in the Scientific Instrument Module nested in the cylindrical Service Module.  Those instrument include a new radar sounder that will scan the moon to a depth of about a mile.  And, of course, he will take us to an from the moon, the primary pilot/navigator for the journey to and from lunar orbit.

Everything appears go as we strap in crowded shoulder to shoulder, The count proceeds as smoothly as can be into its final minutes.  At T-minus 3 min. 6 sec., the automatic countdown sequencer takes over.  We’re ready to put on quite a show, one we will miss.  The Saturn will produce a flame 2,200 ft. long, visible for about 500 mi.   T-minus 2 min.  We perform our final task, aligning the guidance platform.  From now on, our task is to monitor systems.  Propellant tank pressurization underway, all three stages.

T-minus 30 sec. and . . .  

“We have a cut-off.” 

The automatic sequencer has halted the count.  Safing procedures underway.  Keep a close eye on tank pressures, everything.   We have a tense few minutes, sitting on the equivalent of a small atomic bomb.

Everything looking good.  We can begin to relax.  They’re recycling the count to the T – 20 min. point, where we can hold nicely.   OK, it appears the automatic sequencer did not register pressurization of the third stage oxygen tank.   They’re looking at it.

OK, what happened was that a controller saw that the automatic sequencer didn’t pressurize the tank and did so manually, but the sequencer didn’t recognize it.  In effect the sequencer said, if I didn’t pressure the tank then it must not be pressurized!  

“I guess we’re slightly in limbo,” I call to the launch Test Conductor.  I ask if it’s likely we’ll be able to pick up the count.  He reassures us that the chances are good.  

Apparently a circuit in the launch sequencer failed.  They’re looking at a procedure to pressurize the tank manually and send a signal to the sequencer indicating that it pressurized the tank, in effect fooling it to think it pressurized the tank normally.  The Saturn V team at the Marshall Space Flight Center in Huntsville, Alabama, are testing the work around.  They have to proceed with caution and deliberation, lest their fix create a worst problem.

There’s nothing for us to do but wait, and what do in the lull?  Well, it’s a good time to take a little nap.  Yes, I can hear Captain America snoring!

At 11 p.m., we recycle the count to T-minus 22 min.   But we will hold at T-minus 8, where we can hold indefinitely, if the Marshall team isn’t satisfied by that point with the work around.

T-minus 8 min. and holding.  They’re still verifying the procedure . . .  Our launch window for this attempt closes at 1:31 a.m.

Midnight.  In the eastern U.S., it’s now December 7, the 31st anniversary of Pearl Harbor.  At 12:15 a.m., word comes the the reconfigured procedure is good.  We’re going to pick up the count at 12:25 p.m., aiming for a launch at 12:33 a.m., 2 hr. 40 min. late, time we’ll make up with a longer TLI burn toward the moon.

T-minus 4 min. and counting.  The Test Conductor gives his final go.   Approaching T-minus  3 min., we go back on the automatic countdown sequencer.   T-minus 2 min., propellant tank pressurization.  At T-minus 90 sec., we see that the third stage is pressurized.   

We hit T-minus 30 sec. and . . . still counting!   “We’re ready, and we’re go up here,” we call.  Stand by for engine start at T-minus 8.9 sec.  And we have engine start.   We feel the vibrations build, race through our bodies.  We only have a couple windows until the boost protective cover is jettisoned during ascent, yet can see a red glow.  “Look at that light!” I exclaim a second before liftoff.

Capcom Robert Overmyer calls, “Liftoff.”

“Roger.  The clock has started,” I give the traditional liftoff call.  “We have yaw.”   The Saturn V leans away from the launch tower to give a margin during the slow climb by it, which takes 8 sec.

Overmyer calls when we clear it.  

“Roger.  Tower [clear]” I reply.  “Yaw’s complete.  We’re into the roll, Bob.”  The big beast is rolling in its ponderous climb onto the proper heading.

Feel that thing shake, are tossed this way and that like we were rags in the teeth of a rabid dog.  You exclaim, “Wow.  Woosle!” and say, “Everything looks great over here, Gene.”

It’s 49 sec. since launch.  I say on the crew com. loop, “OK, standby for Max — coming through Max Q . . .”  That’s the maximum air pressure on the vehicle.  And she’s really rumblin’ an shakin’ now, heavy vibrations, like a big ol’ freight train, rough and noisy “We’re go at 1 min.,” I radio.

Overmyer replies, “Roger, Gene.  You’re looking great.  Right on the line.”

Through Max Q, and that heavy vibration begins to lift.  The vehicle begins pitching over as programmed.  At 1 min. 48 sec., I say, “OK, we’re out of Max Q.”  Vibrations begin to loosen their grip.  You comment on how quiet it’s getting.

At 2 min. 11 sec., Overmyer calls up, “Seventeen, you’re go for staging.”

“Roger, we’re go here.”

Seconds later, I tell you and Ron, “Standby for inboard.”  We’re accelerating faster, the engines gaining efficiency as we push out of the atmosphere, and so to maintain a 4 g level, the center engine shuts down before the other four.  “Inboard cutoff.”

I give a reminder, “OK, now, hold on after staging, guys.”

I warn, “OK, 5 sec.”  Shutdown, on time, 2 min. 41 sec. since launch.  When the thrust ceases, the whole stack unsprings and we’re tossed forward against our straps.  “Jesus Christ!” Ron exclaims on the crew com. loop.  Staging and second stage ignition 2 sec. later

I say, “I told you to hold on.  Look at that son-of-a-bitch.” We fly through a bright yellow fireball tossed by the first stage, a parting gift. 

“Jesus crimany” Ron says, and we laugh.

I radio, “OK, Bob.  I guess we got all five.”  That means the five hydrogen-fueled engines of the second stage.

And Overmyer says, “And the thrust is go on all five of them.  They’re running good.”

And the ride really smooths out.  “Come on, baby!  Go!” I exclaim on the crew loop.

At 3 min. 19 sec., the escape tower jettisons, taking the boost protective cover with it, giving us a view through all five of our windows.  The tower’s solid motor ignites, and lights up the inside off the boost protective cover in an orange glow.  As the tower and cover pull way, it produces some spectacular fireworks.  Ron exclaims, “Wow! — there she goes!”

We settle in for a nice long ride on the second stage, six minutes more to go on it.  I tell you, “OK, guys, we’ve got a long way to go.”  

Four minutes.  Overmyer calls, “You’re looking real good, Gene.  Right down the line.”

“Let me tell you, this night launch is something to behold,”  I tell him.   However, right now, we only can see the darkness of space.

“Five minutes, Geno, and you’re go down here.  You’re looking great.”

Both you and Ron say you can’t believe how smooth the ride is now.  I tell you, “OK, let’s keep this mother burning . . . We’re only half way there.”   Houston gives us an expected second-stage cutoff time of 9 min. 20 sec. into the launch.  We’re pulling only about 1 g now.  Ron says, “Just like sitting  on the pad, isn’t it?”

We radio, “Seven minutes, Bob.  We’re looking good onboard.”

We were climbing a ladder of milestones, such as the point where we could achieve a stable orbit on the third stage by burning all its fuel, each milestone bringing us closer to the safety of orbit.   We’re now flying parallel to the Earth, in a heads-down position.

Like the first stage, the second stage’s center engine will shut down first, about 1.5 min. before the other four engines, in this case to reduce vibrations.   We’re 7 min. 34 sec. into flight.  “Stand by for inboard.”

“We have inboard cutoff.”

“Roger, Gene, inboard on time.”

We pass the 8-min. mark.  We’re go. Coming up on 8 min. 20 sec.

Overmyer calls, “Seventeen, Houston.  You are go for staging.”

“Thank you, Bob.  We’re go for staging up here.”

Like a prayer, I tell the third stage, the S-IVB, it’s called, with its single engine that must place us in orbit and then after two passes fire again to send up toward the moon, “And little S-IVB — burn, baby, burn.”

We pass the 9 min. mark since launch.  “Ten seconds,” I warn.  Ten seconds until staging.

At 9 min. 20 sec., I call, “S-II cutoff. . . And we have S-IVB ignition.”

Overmyer calls, “Roger.  We see it, and the thrust is looking good on it.”

We see the glow from it, too.  “Geez!”

I say on the crew loop, “Did you see it go past us?”

You say, “We’re right in the flame.”  The flash of separation and ignition tried to overtake us!

The third stage gives a kind of rolling vibration, just chugging along.  We’re pulling less than 1 g.

At 10 min. 7 sec., Overmyer calls, “Seventeen, Houston.  You are go for orbit — go for orbit.”

“Those are kind words, Robert.  We’ go for orbit here.”

“Good show, Gene.”

We’ve still got more than a minute to go.  

“Eleven minutes and we’re go,” I call.

Cutoff comes at 11 min. 42 sec.  We’ve completed the first major step of the mission, achieved Earth orbit.  Now, you’ll only have two orbits, you’re only chance to take in the view of Earth from low earth orbit.  I want you to take a good look, as it’s almost certain none of us will come this this again.

And what a first view of Earth we have:  Out of darkness, a light spreads its arm around the horizon, intensified, bursts into bands of color — behold sunrise.

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