ZERO PHASE
ZERO PHASE
APOLLO 13 ON THE MOON
PART OF THE ALTERED SPACE SERIES
GERALD BRENNAN
TORTOISE BOOKS
CHICAGO, IL
FIRST EDITION, DECEMBER, 2013
Copyright © 2013 by Gerald D. Brennan III
All rights reserved under International and Pan-American Copyright Convention
Published in the United States by Tortoise Books
www.tortoisebooks.com
ASIN: B00H9EZIT8
This book is a work of fiction. All characters, scenes and situations are either products of the author’s imagination or are used fictitiously. Any resemblance to actual events or locales or persons, living or dead, is coincidental.
Front Cover: Image AS14-66-09306 (NASA/Lunar Planetary Institute)
Helmet and cuff checklist photographs provided through arrangement with the Adler Planetarium. Photo editing for helmet photo by Nick Bianco Photography.
Tortoise Books Logo Copyright ©2012 by Tortoise Books. Original artwork by Rachele O’Hare.
PRO. Proceed.
We’ve been thinking about this for years and simulating it for months and now it’s real. 50,000 feet above the surface of the moon. Facing up, looking out the LM windows into blackness. Standing with tension cables clipped to our waists. Gloves and fishbowl helmets on. Flying.
And we’ve just had ullage and the propellant’s settled and the DSKY’s flashing 99. Asking us for confirmation. Powered Descent. Program 63. Braking Phase.
I press the button and call it out. “PRO.” The button does not fire the engine. “4.” It just tells the computer it’s OK to go ahead. “3.” The DPS lights when the AGC wants it to. “2.” We just wait for it. “1.”
Freddo calls: “Ignition.”
It is not dramatic. Changing numbers on the DSKY and a very slight vibration from the DPS. Not as stressful as, say, a night carrier landing. Or a bad day in the simulator, even.
But it is dramatic. It is real at last. I echo: “Houston, Aquarius. We have auto ignition.”
For the first 26 seconds, 10% thrust only. The engine needs to gimbal to make sure it’s aligned with Aquarius’ center of mass. Accelerometers measure vector components along the x, y and z axes, then give feedback to the computer, which sends adjustments to the engine. Nulling out acceleration along the y and z axes and keeping the thrust vector along the x axis so we don’t tumble or spin. Like a toddler wobbling as he finds his balance. But fast. Precise. Automatic feedback loops. A system of systems. Doing it by hand would just foul it up.
Freddo: “Stand by for 26.”
“OK, we have throttle up.”
94% of rated power. 9,870 pounds of thrust. The whole ignition subroutine is called BURNBABY. This is what passes for humor among computer programmers.
“Houston, Aquarius. We are at full throttle.” We feel the floor press gently against our feet.
A 2.6-second-delay. We’re far enough away that the speed of light makes a difference. And finally, the Capcom’s voice: “Aquarius, Houston. Roger that.”
We’re riding the brakes. Orbital Mechanics 101. The descent engine’s thrusting in our direction of travel, slowing us down so we can fall out of orbit. The RCS thrusters fire to keep us in line. Inside our fishbowls we hear muffled sounds. Coolant fans, fuel pumps, hisses. Nothing abnormal.
“Landing Radar, Enable.” Freddo again. Then: “Jim, give me a 2-minute mark.”
I watch the DSKY count down the burn time. “And…mark.”
“OK. H-dot is low. H is a touch high. Waiting on Noun 69.”
“Houston, do we have that?”
The Capcom’s voice crackles: “…quarius, Houston. Guidance just sent it up. Minus One-Four-Zero-Zero.”
Verb 21, Noun 69. I key in the command. Some programmer at MIT realized years ago that most of our computer commands would be simple sentences. Verb, noun. It was a temporary solution. Six years later, we’re flying it to the moon. That’s how it is in engineering. The temporary becomes permanent, if it works. Verb, noun. Display angles. Calculate orbit. Fire engine. Here we’re adjusting the landing point. A white lie. Kentucky windage. The target hasn’t moved. But it’s easier to tell the AGC the target’s moved than to tell it the spacecraft’s out of position.
I hit enter. Accept their adjustment.
Freddo watches the tapes. Compares instruments to printed checklists. At every stage there are indicators of what to do based on the displays, which our controllers are also monitoring in greater detail down in the MOCR. GO or NO GO. (Once we’re on the moon, though, it’s STAY or NO STAY. When the controllers were writing mission procedures, they realized that once we landed, GO could mean “Go! Launch an abort! Get away from the moon!” or “Go ahead and stay.”) Still, if you look close enough, everything in life is a 1 or a 0. Yes or No. Do or Don’t.
“Altitude light OFF, Velocity OFF,” Freddo calls out. We’re getting data from the landing radar, which is behind our backs aimed down. It needs to see the moon. We don’t, not yet.
“All right. Verb 06, Noun 63, and the solutions are 800 apart.”
Houston: “Not bad, Aquarius.”
“I’ll take it. Verb 57, Enter.” We’re telling the AGC to accept the radar data. One of the first things you learn as a pilot: trust your instruments. The human body wasn’t calibrated for these things. When you’re taking off in a jetliner, you can see this. It feels like you’re tilted backwards even when you’re still rolling along the runway. The otoliths in the vestibular system of the inner ear can’t separate acceleration into precise component vectors.
“Let’s have a 5-minute mark, Jim.” Freddo, again.
“And…mark.”
“OK. H is 30,750. Only 250 high now.”
“OK. Verb 16, Noun 68. We are just over 3 minutes to pitchover.”
Neil said walking on the moon was a 1, on a scale of 1 to 10. All you do is get out of the spacecraft. Walk on the moon. No big deal. He said Powered Descent was an 11. Anyone can walk on the moon. The trick is landing on the moon.
Of course, it hadn’t been done before. Landing a manned rocket. They had program alarms all the way down. 1201 and 1202. The rendezvous radar was set to AUTO and ate up too much computing power calculating tracking angles. And they were long on trajectory, so at pitchover everything was unfamiliar. Neil saw the computer was aiming them at a boulder field, so he had to take over. Fly the landing manually. Almost ran out of fuel but he did it. His heart rate was around 150 at landing.
But so far with us, everything’s well within norms. We won’t see more than a sliver of the moon until pitchover. But if everything looks good, I’ll let the computer fly us down.
“2 minutes to pitchover. PGNS to Attitude Hold,” I call. A semiautomatic mode. Not quite manual, but close enough to make us feel like we’re the ones flying. Here the computer adjusts for all the variables (like sloshing fuel) and holds the LM steady relative to its trajectory. It stays in that attitude until you nudge the stick, and when you let go, it holds the new attitude. A good compromise, given the healthy size of the average astronaut’s ego. (I like to think mine’s in the lower half of the bell curve. At least in our office. But who knows? Maybe everyone thinks that way.) I give a few quick nudges to make sure it’s responding properly in case I do have to fly the landing. “Everything’s looking good. Switching back to auto.”
“PGNS – AGS is updated,” Freddo says. A quick feed of data to the Abort Guidance System, in case we have to abandon the landing approach. But routine. Probably unnecessary today. So far, everything is smooth.
“1 minute to pitchover.” I call.
“I’m starting the camera.”
“30 seconds.” We’ve been memorizing la
ndmarks for months. Patterns of holes. If everything’s going as smoothly as the instruments say, I’ll see Cone Crater on pitchover.
Freddo: “And we have pitchover.”
The LM pivots on its own. Leans forward like a man waking up. We see the 8-balls rolling down in sync like mechanical eyes closing. The lunar horizon rises in our windows and everything is clear and perfect. Beautiful in the moon’s stark strange way.
“Houston, Aquarius, we have pitchover and Program 64 is running.”
For a moment, I’m confused. But the DSKY’s given us an LPD angle. 42⁰. There are sighting marks etched into the LM windows, and when I look along them at that angle everything becomes familiar in an instant.
“There we are! How ‘bout it.” I’m excited at last. (We’re stuck with mild commentary because the world is theoretically listening. They’re probably not, since this isn’t the first or even the second landing, but still. Like any publicly-funded institution, NASA has to adhere to a lowest-common-denominator respectability. Otherwise I’d be tempted to use a profanity or two. Tom Stafford and/or Gene Cernan accidentally let slip a “son of a bitch” during a moment of crisis above the lunar surface on Apollo 10. And I guess you’d say they caught heck for it afterwards.)
“Hot dog!” Freddo’s in fine spirits, too. “Right down the line. Outstanding.” Of course, this has all been new to him. Even our two earth orbits prior to TLI.
“This is outstanding!” I echo.
Again I survey the terrain. A dead world. Brownish-gray with sharp shadows. Empty. I was one of the first three human beings to see it up close, back on Apollo 8. One of the first to see the far side, which people mistakenly insist on calling the dark side. The first to take a picture of the earth from the moon.
But there’s no time for sightseeing or pondering right now. Without me even needing to ask, Freddo turns back to the instruments. His job title is Lunar Module Pilot. Unless something really goes wrong, he’s just calling out information and monitoring the systems. Not as dramatic as command. But obviously still crucial. “2500. Down at 63.”
“Roger that.”
“2000. Little fast.”
“OK.” I watch the cross-pointers, scan the other instruments, then look back outside along the LPD angle. Craters getting larger, but it still doesn’t look much different. Like parachuting. Until you’re really close to the ground, you don’t feel all that close. Then it all happens very fast.
“1000.”
“Couple little craters. I’m going to redesignate. Two clicks left, one up.”
“500 feet, 16 feet per second. Fuel’s 11%.”
“I’m in Attitude Hold.” I’ve gone to semi-manual controls. I’d wanted to autoland. But better safe than sorry.
“OK. 9% fuel. 250 feet. Looking good. Two feet per second forward, three feet per second down.”
“OK, I’m gonna head down.” On the console I can see the cross-pointers. A very simple instrument, easy to read: a horizontal line and a vertical line. When they’re both centered you’re not moving forward or back or side-to-side. Stable. Which is what you want on landing. Move too fast laterally on touchdown and you’ll tip over.
“150 feet. Descent quantity light.”
“Roger that.” Under two minutes of fuel left. As expected, but still a concern. And we’re in what Neil called the Dead Man’s Curve. For most of the descent, we can press a button to abort if the DPS fails. But for about 10 seconds here, we’re too low and sinking too fast to pull it off. We’d crash before the ascent engine gave us enough delta-v. It happened in the sims once. But Houston’s been monitoring our readouts, and they haven’t said anything.
“100 feet.” If Freddo’s anxious, I can’t tell.
“Picking up a little dust.” In this airless place, the scene beneath us likely hasn’t changed in millennia. And now the DPS is blowing moon dust smoothly out in all directions. No clouds, no billows, just streaks heading outward until the dust falls back down. It looks a good bit clearer than the footage we saw from 12. I can see a few craters underneath. And one or two boulders. Rocks in the stream.
“5% fuel.”
“Heading down.”
“50 feet. 3 feet per second. 40 feet. Down at 2-and-a-half. We’re null on lateral velocity. 20 feet, 2 feet per second. 10 feet.”
There are sensors on strips of foil hanging from the LM footpads. They’ll let us know when they’re touching the surface so we can manually cut the engine. I wait for it. It is almost done.
Freddo: “Contact light.”
The blue LUNAR CONTACT light is on.
“OK, Engine stop.” I mash the button and we fall the last couple of feet and the LM hits with a very slight rattle.
“And we are on the surface!” Freddo claps me on the shoulder.
The RCS system isn’t designed to know we’re down. It wants to keep firing the thrusters to correct our attitude. I nudge the stick to reset it to our current attitude. Since we’re stationary, it won’t need to do anything to hold that. “Houston, Aquarius, we have a good landing. Very slight plus-Z angle. But we are down.”
“Well done, Aquarius,” they reply at last. “Smooth piece of work.”
A few months ago, some journalist pointed out to me that, when we got to the moon, I would undoubtedly be the most travelled human in history. The first man to go into space four times. The first to go to the moon twice. On top of two Gemini flights, the first of which lasted 14 days. If you cracked me open right now and saw an odometer, it would read well over 7 million miles. If God sorted the list of homo sapiens in rank order by distance travelled, descending, the name at the top would be Lovell, James.
But I’m not dwelling on these things. There’s too much work to be done.
Besides, I don’t feel different. I’m just a captain responsible for his crew. And that trumps any self-trumpeting. So my next words on this monumental occasion are: “Helium Reg 1 is closed. Talkback is barber pole.”
“Recycling the Parker valves,” Freddo calls out. “Closed, open, closed, open, open, open, open, open.”
“Oxidizer and fuel are gray. Master ARM ON.” We’re running through the post-landing checklists. Safing the spacecraft and preparing for an emergency liftoff in case something goes really wrong, like the LM starts tipping over or the pressure hull springs a leak after the jolt from the landing. The LM’s the flimsiest thing the Grumman Iron Works ever built. The cabin’s as thin as three sheets of aluminum foil in places. I know Tom Kelly and his team, and I know they did a superb job on this thing. It’s sturdy enough to get the job done. But you can’t take unnecessary chances on top of the necessary ones. You have to prepare for everything.
Freddo: “Descent temperature and pressure coming down.”
The checklists say we have to prepare for an immediate post-landing abort at T + 1 or T + 2. If too much time passes, we wouldn’t be able to launch and catch up with the CSM before its next orbit. But I know they’ll give us a STAY at both time hacks. Everything has gone incredibly smoothly. Until powered descent I was almost bored. Nothing before that was new to me. This of course is new, but I’ve been desensitized by simulations and past missions. I almost have to remind myself it’s new. Which is OK with me. A smooth, professional mission to keep the program rolling. The first pure science mission in the program. Apollo 13.
•••
Of course, we are a little late getting to the moon.
We’d been slotted for an April launch. And everything was on track until a couple days before. But Charlie Duke on the backup crew caught German measles from a family member. And Ken Mattingly on my crew had never had it. They said there was a risk he’d get sick while we were on the lunar surface. So there was some noise about breaking up my crew and putting in Jack Swigert from the backup crew as my CMP. And Deke toyed with the idea, I think. Even though no one had ever jumbled up prime and backup crews like that so soon before launch.
Keeping the crew together posed its own problems. We could laun
ch with the slight possibility of a serious medical issue. Or we could wait a month. (Or more precisely, a lunar cycle.) We needed a landing date where the sun angle on our landing site would be about 15⁰ over the lunar horizon. So we’d be in bright sunlight but there would be deep long shadows in the craters. Plenty of definition and contrast to help us better judge where to set down during the landing. And that meant leaving the Saturn V on the pad four extra weeks and doing another CDDT at the end of it. Figuring out which systems needed to be flushed and purged and re-calibrated.
The systems engineering types around the MSC (usually the ones who came to Apollo by way of the ICBM programs) always talk about tradeoffs. You have to analyze the risk caused by one thing (switching crew members around at the last minute) against the risk caused by something else (keeping a highly sophisticated launch system full of finely-calibrated devices and corrosive propellants out on the pad for an extra month) against the risk of yet another thing (keeping the original launch date and leaving the crew intact and taking a chance on a Command Module Pilot getting sick). Then you make the best decision for achieving your end result. I expected them to take a chance on the first launch window with Ken. Failing that, I figured they’d launch us with Jack in April. But they kept us together and waited.
And the world-at-large didn’t care.
Not that I expected otherwise, but still. Kennedy’s goal had been more than met, so maybe it didn’t matter to the public any more. We hadn’t just landed a man on the moon and safely returned him. We’d returned two men safely two times. So when we changed our launch date by a month it didn’t even make the front page. My teenage daughter Barbara told me over the phone that we’d been displaced by Paul McCartney’s announcement that the Beatles had officially broken up. (I asked her which was more important. She laughed and said, “I dunno, dad. Launch delays are temporary…”) And this was soon overshadowed by far more serious events. Stories of which we were dimly aware, given the intensity of our refresher training, the length of our workdays, and the consequent difficulty of something as simple as relaxing with a newspaper. At the end of April, the U.S. sent forces into Cambodia. A few days later, the National Guard shot four kids at Kent State. A world of uncertainty. As troubled as it had been when we’d first orbited the moon in that lunatic year of 1968.
Zero Phase Page 1
