Moon Lander: How We Developed the Apollo Lunar Module (42 page)

Through all this turmoil the LM Intrepid was snugly nestled inside the protective conical structure of the spacecraft/LM adapter, where it was when the lightning had struck. Inactive and inert, I did not think the LM had sustained any damage, since the major lightning current would travel through the outer skin of the SLA. However, within sensitive electronic microcircuits there was always the possibility of inducing damaging secondary currents in the tiny etched conductors and components, whenever a strong current surge and changing magnetic field was nearby. While LM was inaccessible, there was not much we could do except worry. I asked our section heads to review all electrical and electronic components with their suppliers, to identify those most susceptible to lightning-induced damage. If we could verify the integrity
of some of the most susceptible items, we would gain confidence in the LM’s overall status.

Half way to the Moon, the crew entered the LM and performed housekeeping and communications checks. Everything seemed all right, but little had been tested. Not until they were in lunar orbit, only six and a half hours before planned touchdown, did Conrad and Bean enter the LM fully suited, activate all systems, and put Intrepid through the extensive powered descent initiation (PDI) checklist. With all eyes in Houston and Bethpage on the monitors, no discrepancies were seen. Our spindly, fragile-looking Intrepid had survived the great balls of fire. I felt greatly relieved, even though I had expected this outcome and confidently predicted it to my associates.

Apollo 11 had landed four miles from its targeted landing point, and for the first few hours Houston and the astronauts were trying to determine exactly where on the Moon they were. Exasperated, Gen. Sam Phillips, Apollo program director, demanded a pinpoint landing for the next mission. To make the requirement clearly visible, NASA decided that the next mission, to the Ocean of Storms, would include a walk to the unmanned Surveyor 3 spacecraft; that had landed there in April 1967. To achieve pinpoint landing capability would require inventing new guidance techniques beyond those available for Apollo 11. Highly accurate landings were essential to efficient lunar exploration because they allowed scientists and geologists to plan and discuss with the astronauts, in detail and in advance, the exact route, objectives, and techniques to be used during each excursion onto the lunar surface. Without knowing their exact surface position, much valuable time on the Moon would be wasted in ad hoc revision of the geological exploration traverses and in orienting the explorers to alternate landmarks.

A young NASA mathematician named Emil Schiesser made the crucial breakthrough. He devised an elegantly simple scheme that used the Doppler shift pattern of radio frequency communications from the LM.
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By comparing the predicted Doppler pattern with the actual observations, ground control’s computers could calculate the deviation in the LM’s real trajectory from the targeted preprogrammed flight path. NASA flight controllers had already been using this technique to analyze translunar flight trajectories. In meetings of Bill Tindall’s mission planning analysis group, a brilliant technique was devised to get the flight path correction information into the LM’s computer. The computer would be told the target landing point had moved by the amount necessary to cancel out the deviation between the real and the predicted trajectories. This required the pilot to enter only a single number into the LM’s data entry keyboard.

LM-powered descent on Apollo 12 went beautifully. The computer overload problem that had produced heart-stopping program alarms for Armstrong and Aldrin had been corrected simply by changing software instructions to no longer require the computer to keep updating and storing
rendezvous radar data with the CSM’s position when the landing radar was operating during powered descent. When Intrepid pitched forward for the final descent at seven thousand feet, Conrad anxiously scanned the lunar landscape below, then gave an exultant war whoop: “Hey, there it is. There it is! Son of a gun, right down the middle of the road!”

He recognized the Snowman crater, on whose rim Surveyor 3 rested, far ahead in a sea of other craters. At an altitude of four hundred feet he took control manually and skillfully landed Intrepid close to Snowman’s rim, about six hundred feet from Surveyor 3. He performed the final one hundred feet of descent primarily on instruments, since his view of the surface was largely obscured by dust kicked up by the descent engine’s exhaust.
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When the blue lunar surface contact light went on, Conrad shut the engine down and Intrepid thumped firmly onto the ground.
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They had achieved a perfect pinpoint landing. There was no postlanding excitement as on Apollo 11, since a simple procedural change had solved the fuel-line pressure buildup problem. (We delayed venting the descent propellant tanks after landing, giving the descent engine time to cool off.)

Conrad and Bean were on the Moon for thirty-two hours and performed two moonwalks totaling seven and three-quarter hours. They made the first deployment of the Apollo lunar surface experiments package (ALSEP), an expanded array of scientific instruments that included a seismometer, a magnetometer, an atmospheric particle sensor and a central transmitting station to relay ALSEP’s data to Earth. ALSEP was designed to gather and transmit data for five years, and the instruments were so sensitive that the seismometer detected the astronauts’ footsteps as soon as it was turned on. We had modified LM-6’s scientific equipment bay to accommodate ALSEP and made special external mounting provisions for the radioactive thermoelectric generator (RTG). It used a radioisotope that would provide power to the ALSEP even during lunar night. Because of safety concerns in event of a launch failure, the power source was encased in ablative insulation capable of reentering the Earth’s atmosphere.

On their second excursion Conrad and Bean walked to Surveyor, inspected and photographed it, and took back samples to show the effect of two and a half years of lunar “weathering” on various materials. They also gathered rock and soil samples from the rim of Snowman crater and other craters in the vicinity, packing more than seventy-five pounds of samples for return to Earth. They kept up a running commentary on what they were seeing and doing, including many excited cries of awe and wonder. It was a pleasure to share their delight in the new world they were exploring.

As the time for lunar liftoff approached, tension mounted both aboard Intrepid and in Houston. Conrad told Bean not to worry because if the ascent engine did not work, they would become “the first permanent monument to the space program.”
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In SPAN I worried more about the rapid sequence of explosive-device
firings that had to take place to separate the ascent and descent stages. All the pyrotechnics were fired by squibs of very thin wire—could the lightning strikes at liftoff have induced currents that burned them out? There was no way to tell. A positive sign was that all prior explosive devices had worked as commanded to deploy the landing gear and to pressurize the ascent and descent propellant tanks and the reaction control system. I just had to hope that the remaining devices were also unimpaired.

The best thing about lunar liftoff was that you knew in an instant if it was successful. And it was, as the ascent stage separated smartly from the descent launch platform and rapidly accelerated toward lunar orbit, Yankee Clipper, and the waiting Dick Gordon. Rendezvous was again a majestic, slow-motion maneuver, precisely executed, and the spacecraft docked and latched together without problems. We heard the joyous cries as the long-separated shipmates embraced and congratulated one another on their good fortune. Apollo 12’s crew was expressive and demonstrative, and they sometimes forgot to turn their cabin microphone off, so we in Houston could briefly share in their joy.

Soon the LM’s part of the mission was over, and the crew was Earthbound aboard Yankee Clipper. My colleagues and I returned to Bethpage and watched the splashdown and aircraft carrier recovery in the Mission Support Room. I savored the Apollo 12 experience—although there had been plenty to worry about, nothing had gone wrong. Except for failure of the portable TV camera, which Al Bean had burned out by pointing it at the Sun early in the first moonwalk, every mission objective had been met or exceeded. NASA was impressively able to handle unforeseen emergencies like the lightning strikes, and the entire mission support team, NASA and contractors, was growing more efficient and professional. We were learning from each mission and making many improvements in the way we operated. The number of LM anomalies during the mission was lower than on any previous mission—a positive trend for each mission thus far.

Apollo 12 shifted the goal from landing on the Moon and surviving to purposefully exploring the Moon. Clearly the Apollo program was not just a stunt, as some detractors had charged, but a serious and unique opportunity to answer scientific questions that had long puzzled mankind. Where did the Moon come from? How was its origin related to Earth’s? How old was the Moon, and what was its geologic composition and history? We would soon have some answers to these and other cosmic questions.

Swept forward on a rising tide of optimism, I decided not even to cover the next mission in Houston but to leave it in the capable hands of my colleagues while I stayed up at MIT in the Sloan Fellows program.

Even at the great distance from Moon to Earth, the irrepressible, bubbling personality of Pete Conrad and his crew had made Apollo 12 unique—a highly successful and productive mission that was also an adventure and a privilege shared by all those who supported it.

17

Rescue in Space

Apollo 13

I groped for the ringing bedside telephone in the midnight darkness. Knocking the receiver to the floor, I groaned as I snapped on the light, shattering for good any pretense of sleep. I felt my wife stir protestingly beside me as I fumbled to retrieve the receiver, trying not to wake her.

“Tom, have you heard the news?” asked the crisp, worried voice of my Grumman colleague Howard Wright.

Negative grunt.

“Well, turn on your radio—Apollo’s in trouble. There’s been an explosion or something. The company’s chartering a plane to fly us to Bethpage. Meet me at the general aviation terminal at Logan Airport at 1:30.”

“Are they alive?”

“Yes, but they’re in real trouble.”

They were in trouble all right, and would probably have to use the lunar module as a lifeboat. There wasn’t time for Wright to tell me more than that. He promised to fill me in on the details at the airport.

Joan looked at me wide-eyed with concern.

“It’s Apollo,” I told her. “They want me to get down to Bethpage right away.” We were living in the Boston area on a temporary one-year assignment while I attended the Sloan Fellows management program at MIT. After seven years of total dedication to designing and building LM, and following the successful first lunar landing of Apollo 11, the company decided that I could use a change and allowed me to compete for a Sloan Fellowship, which I won. Howard Wright was also in Boston on company sponsorship attending an advanced management program at the Harvard Business School.

The radio spewed out a stream of ominous phrases: “Apparently an explosion … difficulty maintaining control … fast running out of oxygen, water, and electric power … Mission Control assures us that the crew is, for now, safe, and has several options for survival.” As the announcers stumbled over
unfamiliar technical terms and space jargon, there was no mistaking the excitement and concern in their voices. Could this be the night when America’s vaunted manned space program would go down to defeat and disgrace, after such a long string of stunning successes, including two manned lunar landings and explorations? The grim prospect loomed of three brave men gasping and suffocating in space while the whole world watched and listened, of their shriveled mummified corpses remaining permanently in orbit as a monument to mankind’s overreaching and America’s technological arrogance.

Two of the three men who were exposed to the unrelenting peril of space were my friends and professional associates. Fred Haise and Jim Lovell had each spent many days at our Spacecraft Assembly and Test facility in Bethpage, putting the lunar module through its paces against test and checkout computers. The third astronaut, Jack Swigert, I had met briefly in Houston, but I knew he was cut from the same competent, no-nonsense test-pilot cloth as his crew mates. I could picture the three of them, jaws jutting, brows furrowed, as they tried to figure how to work their way out of yet another tight spot. They would be carefully checking all instruments on board the spacecraft, looking through the oxygen and electrical power system diagrams and emergency procedures, and discussing their options in calm, matter-of-fact voices. The imminence of danger would not alter their professional habits.

It was exciting to think that the lunar module might become their lifeboat, the key to their rescue. After the first successful lunar landing, Volkswagen, whose VW Beetle was considered an ugly car, ran a full-page ad in the
New York Times
showing the LM with headlines trumpeting, “It may be ugly, but it gets you there.” Where LM was concerned, beauty was definitely in the eye of the beholder, and to me she was beautiful.

Joan routed our oldest son David out of bed to stand watch over the rest of our six children while she drove me to the airport. I was still stuffing LM reference data into my briefcase as we left. It was a beautiful clear April night, and when I met Wright on the tarmac we both strained irrationally to see Apollo up there near the bright Moon. He had talked with some of our people in Bethpage and Houston and determined that NASA definitely planned to execute the LM lifeboat mission, and quickly, as life-sustaining supplies on the mothership command module were rapidly seeping from a mortal wound in its oxygen system resulting from the explosion of an oxygen tank in the service module. There seemed to be no reason not to try the lifeboat approach, for although it had never been rehearsed with either the flight or ground crews or written into specific operational procedures, we had studied the rescue possibility early in the LM’s design and had provided additional oxygen, water, and power capacity to cover it.
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However, to go from a preliminary systems design study done six years earlier to real-time execution of a complex and unplanned sequence of space maneuvers by flight and
ground crews untrained in its specifics was quite a leap. We would soon find out whether men and machines were up to it.