Moon Lander: How We Developed the Apollo Lunar Module (40 page)

His resolve did not go unnoticed by the NASA leadership. NASA Associate Administrator for Manned Spaceflight George Mueller, Apollo Program Director Gen. Sam Phillips, Apollo Spacecraft Director George Low, and Manned Spacecraft Center Director Bob Gilruth all made a point of dropping by to see Evans during the missions and occasionally waved or nodded to him from their consoles in Mission Control through the VIP area’s glass partitions.

The outbound voyage of Apollo 11 unfolded smoothly. The real mission, like Apollo 10 before it, was much quieter than a typical mission simulation, with few anomalies and no hard failures. Two and a half days after Earth launch, Aldrin entered the LM and checked out its systems. We eagerly
scanned the wealth of data that came flooding down from Eagle onto our screens and were delighted to see that she had come through launch and translunar coast in good shape. Just after Apollo 11 passed behind the Moon, out of touch with Earth, the service propulsion engine was fired for six minutes to send the spacecraft into lunar orbit. The crew performed navigation checks, then a second short burn to circularize the lunar orbit at about sixty thousand feet above the surface. Armstrong and Aldrin entered Eagle and performed a thorough systems checkout. There were no anomalies. They shut her down again and returned to the CM for a nine-hour eat-and-rest period—the last break before their descent to the Moon.

During quiet mission periods I rotated duty at the Grumman desk in SPAN with my deputy Howard Wright and Chief Subsystem Engineer Bob Carbee in eight-hour shifts. When not on duty we could continue to watch the action from the VIP area or the Engineering support floor in Building 45 or return to our nearby motel for food and rest. Even my motel room had the NASA public affairs channel and, of course, a TV. For the landing all three of us wanted to be in the SPAN Room, and NASA, though concerned that overcrowding might detract from our effectiveness, reluctantly concurred.

After a fitful rest Armstrong and Aldrin entered Eagle and activated her systems again. Leaving Collins alone to tend Columbia, the hatches between the two spacecraft were closed, and with a “pop” the vehicles separated.

“The Eagle has wings!” Armstrong called out exultantly, as he maneuvered his landing craft for the first time, pirouetting in front of Columbia’s windows so Collins could visually inspect Eagle. While behind the Moon, a brief burst from Eagle’s descent engine dropped her below and behind Columbia, heading for an orbital low altitude (perilune) only nine thousand feet above the surface, from which point a continuous twelve-minute burn of the variable thrust descent engine would complete the landing.

When Houston again acquired Eagle as she emerged from behind the Moon, less than half an hour remained to touchdown. I thought I would explode from pent-up nervous energy, and yet I was fascinated as one after another the events required in the flight plan flashed by. LM’s rendezvous and landing radars were both on and operating; everything else was looking good. After the leisurely translunar coast phase, mission events whirred by as though on fast forward. Shortly after the final descent engine burn began, several program alarms occurred in rapid succession. In each case the flight controllers assured the crew they could reset the warning indicator and press on. One of the alarms was due to an improper switch position in LM; two others were momentary computer memory buffer overloads with data coming in from the radars. These were resolved by NASA so quickly that Grumman support input was neither possible nor necessary. We held our breaths as Armstrong said he was taking over manually to avoid boulders he could see at the programmed landing point, listening as Aldrin called out the few feet remaining of altitude and velocity. Then they were down, engine off, and we heard Armstrong’s historic words: “Houston, Tranquility Base here. The Eagle has landed!”

Supporting Apollo 11 in the Spacecraft Analysis Room.
At desks, left to right:
Tom Kelly, Owen Maynard, Dale Myers, and George Merrick. (Courtesy NASA) (
Illustration credit 15.1
)

Cheers resounded in Mission Control and the SPAN Room, but Flight Director Gene Kranz quickly restored order, reminding us of the heavy post-landing activity ahead, including immediate preparation for liftoff in case lunar stay had to be curtailed for any reason. Carbee, Wright, and I embraced each other in joy and relief that the landing was safely accomplished. Seven years we had worked for this moment; how marvelous to experience it! I saw tears streaming down Carbee’s cheeks and felt a lump in my own throat as well.

Our joy was short lived. Within a minute after landing my phone rang. It was Manning Dandridge over in Building 45, pointing out to me that the pressure and temperature were rising in a section of fuel line between the descent helium heat exchanger and the fuel control valve on the descent rocket engine. This was quickly picked up on the net by the LM propulsion flight controller, Jim Hannigan. Dandridge and George Pinter (our supercritical helium expert) concluded that after engine shutdown, cold helium froze the fuel remaining in the heat exchanger, trapping liquid fuel between the frozen fuel slug and the closed engine fuel valve. Heat soaking back from the hot engine parts after the long burn increased the pressure and temperature of the trapped fuel.

Celebrating the Apollo 11 Moon landing.
Left to right:
Arnold Whitaker, Bob Carbee, Lew Evans, Tom Kelly, Jim Leather, Frank Canning, and John Coursen. (Courtesy Northrop/Grumman Corporation) (
Illustration credit 15.2
)

Hannigan left his console in the MOCR and joined us in SPAN. We put Dandridge and the Building 45 people on the speaker phone; Gerry Elverum, the chief engineer of the descent engine for STL was with them. As the temperature exceeded three hundred degrees Fahrenheit we became very concerned. The rocket fuel was a mixture of two forms of hydrazine, and at temperatures above four hundred degrees it became unstable. Extrapolating the rate of temperature rise suggested it would exceed that limit in ten minutes. We all felt that the consequences of an explosion, even of the relatively small amount of fuel remaining in that short section of line, was unpredictable and unacceptable. Phone calls to other rocket experts at Aerojet and Rocketdyne confirmed this view.

Dandridge suggested the possibility of “burping” the descent engine by commanding it to fire, then immediately shutting down, to momentarily crack open the engine fuel valve to relieve the pressure and temperature. George Low and Gene Kranz then joined us in SPAN and asked a barrage of pertinent questions, especially concerned whether we could cause the LM to tip over.

We decided that a momentary flick of the manual firing button was the best procedure. Since the trapped volume of fuel was small, even rapid opening and reclosing of the valve would provide major relief in pressure and temperature. Temperature was now over 350 degrees; we had only a few minutes left to act.

Low decided to do it and returned to Mission Control to explain the procedure and reasoning to CapCom Charlie Duke for transmission to the crew. Before he could place the call, however, nature took over and solved the problem for us. Heat soaking back from the engine melted the fuel ice plug in the heat exchanger and the pressure abruptly dropped to a low value. We looked at the screen in amazement for a few seconds, then broke into smiles and cheers of relief. I collapsed back into my chair and realized that I was drenched with sweat. What a welcome to the Moon! To this day, when asked how I felt right after the first LM landed on the Moon, I say that for ten minutes following touchdown I was too busy and worried to even know they were there.

The crew was working their postlanding checklist and, finding all in order, received clearance to stay on the Moon. They had no inkling of the propulsion system drama that had just played out six feet beneath them. The only problem they reported was that the mission timer had stopped and would not reset—strictly a nuisance item, although we would have to find the cause and fix it before the next mission.

I also carefully looked over the LM data, but I could find nothing else wrong. At last I could believe the landing was successful! Soon, in addition to relief, I felt a growing curiosity about the details of the landing site. Before they proceeded with the required practice liftoff countdown, the crew spent a few minutes at Eagle’s windows taking a look at their new surroundings. I imagined the scene at Tranquility Base as the crew described the strange other world outside. They saw a flat plain, pockmarked with craters and studded with rocks and boulders of diverse sizes, and dry, dusty-looking soil. Colors varied from white to shades of gray and brown, depending on the Sun’s angle to the object, and the sky was jet black with thousands of stars showing, graced by the spectacular blue-and-white bauble that was Mother Earth. The brief reports from the crew mostly stuck strictly to factual descriptions but occasionally ventured a characterization, such as “awesome beauty” or “magnificent desolation.” They returned to the practice countdown, which verified all LM systems and configured them for liftoff. Then they settled down in
Eagle for the scheduled activities of eating and sleeping. My colleagues and I took advantage of the quiet period to eat in the MCC cafeteria, where we exchanged congratulations with Bob Gilruth and George Low. We then had a rest period of our own at our nearby motel.

I slipped into a sound sleep when the telephone woke me. It was Bob Carbee in SPAN with word that the crew was getting ready to come out onto the Moon early, three and a half hours ahead of the flight plan. How could they sleep when they had just landed on a new world? Excitement ran high in the SPAN Room. I listened eagerly to the crew preparing for egress, donning spacesuits and checking out and donning the backpacks. The crew provided running commentary of their activities. Despite their care in moving about the cabin, Armstrong accidentally broke off the button of a circuit breaker, which protected the ascent engine arming function, with his bulky backpack. I asked our Grumman support people in Building 45 and at Bethpage to work out an alternate procedure for arming the engine without that circuit breaker. There were several different paths for executing this critical function, so I was confident that we could find a way around it.
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The astronauts depressurized the LM cabin, opened the forward hatch, and Armstrong cautiously backed out onto the “front porch” platform, with Aldrin giving him helpful steering instructions from inside. With a black-and-white TV camera on LM and the whole world watching, he climbed down the ladder and set foot on the Moon: “That’s one small step for [a] man; one giant leap for mankind.”
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Armstrong experimented with various gaits for moving about on the powdery charcoal-like surface, settling on a lengthened walking stride. Aldrin joined him, and for the next two and a half hours they explored the area. They took the TV camera outside and mounted it on a stand, sharing the sights and their activities with the world. They planted the American flag on the surface and answered a telephone call from President Nixon. Opening the scientific equipment compartment on the LM descent stage, they deployed seismic sensors, a solar wind experiment, and a laser reflectometer. They took photographs and gathered lunar soil and rock samples. So little time, and so much to see and do!

I was fascinated to see how well the LM had weathered the landing. Touchdown was gentle, so the energy-absorbing landing-gear struts were hardly compressed at all and the footpads had only sunk about two inches into the dust. The silver, black, and gold LM was the only spot of color in an otherwise gray world. The astronauts adapted well to the Moon’s gravity, and with a little practice they were confidently hopping about the area, investigating interesting craters, boulders, and rocks. Even in the ghostly black-and-white TV images the strange timeless beauty of the barren moonscape was evident. How privileged I felt to be playing a part in such an adventure.