WHAT IF TWO THRUSTERS GOT STUCK in the on position? What if the thrusters overheated due to heavy use during landing? Would this generate an alarm during the crucial landing or postlanding phase of the mission?
Jerry Woodfill spent another night lying awake, thinking about the Caution and Warning System onboard the Apollo spacecraft. It was his system—he was the lead engineer—and in his mind, the alarm system personified all the work that had been done since the Apollo 1 fire in regard to crew safety. But what-if questions about alarms for the LM thrusters kept nagging him.
The Caution and Warning System monitored critical conditions of the spacecraft, and any malfunction or out-of-tolerance condition—such as problems with the propulsion systems, environmental control or the guidance computer—caused a status light to illuminate. It also activated the master alarm, sending an alarm tone to the astronauts’ headsets. The master alarm light and tone would continue until one of the crew reset the master alarm circuit.
“My system had two categories of alarms: one, a yellow light for caution when the astronaut could invoke a backup plan to avoid a problem, and the other, an amber warning indication of imminent life-threatening failure,” Woodfill explained. He worked with engineers and managers on all the other parts of the spacecraft that the warning system monitored for failure to set the “trip level” of what conditions would set off an alarm. He also conferred with the astronauts on writing up the instructions for their in-flight operational checklist so they understood the alarms and knew what to do should they sound.
What Woodfill calls “nuisance alarms” were the most difficult to figure out. This type of alarm came on when no actual problem existed. For example, simply switching on a system might trigger an alarm until the system reached its operational state. Each instance of such an alarm had to be known by the crew and flight control team so that the occurrence of a nuisance alarm would not mask an actual problem. Worse, an errant alarm might confuse the crew or distract them during important moments of the flight.
Scores of such potential alarms became Woodfill’s most challenging role as the warning system engineer for both the lunar lander and CM. Woodfill was scheduled to fly to New York to meet with Jim Riorden, the Grumman manager of instrumentation. The two men would go over the LM’s Caution and Warning System, so Woodfill took the opportunity to discuss some of those middle-of-the-night contemplations.
“Jim, what would happen after the lunar landing when the heat from the hot engine warms our temperature sensor in the landing radar warning circuit?” Woodfill asked. “Might that trigger the landing radar alarm unnecessarily while the astronauts are out on their EVA? They’d have to return to the LM, cutting their exploration short to discover the alarm’s cause. They’d find nothing more than a nuisance alarm. After landing no one cares about the landing radar. It had served its purpose.”
“Jerry, you may have something there,” Riorden said, pondering the idea. “We’ll run a thermal analysis on the landing radar environment from touchdown to lift-off.”
A week later, Riorden called Woodfill, saying that the voice in his head had been correct. That nuisance alarm would very likely occur under the postlanding conditions, as Woodfill surmised. The cost to correct the problem was negligible—one wire removed from the warning system.
Woodfill tried to imagine what NASA management and the news media would think if the first astronauts on the Moon were ordered to end their exploration hours early due to a nuisance master alarm. He ran some calculations on the estimated cost to the program, and he very likely earned his lifetime salary with NASA many times over in those few minutes of discussion with Riorden.
AS NASA PREPARED THE APOLLO 7 spacecraft for the first crewed flight in Earth orbit, the Soviet Union launched a series of robotic spacecraft called Zond that looped around the Moon and flew back to Earth. Then new intelligence photos from the CIA appeared to show the USSR preparing its own crewed lunar mission. These events prompted an August 1968 meeting between George Low, Robert Gilruth and Samuel Phillips (head of the Apollo Program Office at NASA Headquarters). Low suggested something bold: If the Apollo 7 mission was a success, change Apollo 8’s flight plan from another Earth orbit mission to a circumlunar mission and have the crew orbit the Moon. At first, Phillips and Gilruth expressed shock at such an idea, but they quickly became intrigued. Delays with the LM meant it wouldn’t be ready for Apollo 8’s flight anyway, Low argued, and to send an Apollo flight around the Moon just might preempt any attempt by the Soviets to get to the Moon first. It would build momentum for NASA and advance scientific knowledge of the Moon. A future landing site could be observed and documented.
But would the flight hardware and the crew be ready for such an audacious mission?
More meetings ensued, adding the input of Christopher Kraft, Gene Kranz, Deke Slayton and other mission managers and planners, including Wernher von Braun, since this would involve sending the first crewed flight of the Saturn V to the Moon. Was all of this even remotely possible? Almost everyone who heard the idea had the same reaction: initial shock quickly turning to intrigue. This daring, gutsy move would be absolutely pivotal for meeting the “in this decade” goal, as well as getting to the Moon before the Russians. But it also—if it was successful—would very likely advance the timeline for a mission to land on the Moon. Deke Slayton called in Frank Borman, currently training as commander for Apollo 8. In a matter of minutes, Borman was all in. He and his crewmates Jim Lovell and Bill Anders met with Christopher Kraft, Bill Tindall and several members of the Mission Planning and Analysis Division team, and in one afternoon they outlined the basic parameters of the mission. A launch window for December 21 of that year offered the first chance that worked for the launch teams, recovery teams and all the other mission planners. Preparations went ahead, and all those who had been briefed about this new Apollo 8 mission were told to keep it secret. But, as Gene Kranz later noted, “it was like trying to hide an elephant in your garage.”
View of activity in the Mission Operations Control Room in the Mission Control Center. The flight director’s console is in the foreground. Eugene F. Kranz, chief of the MSC Flight Control Division, is in the right foreground. Seated at the console is Glynn Lunney, head of the Flight Director Office, Flight Control Division. Facing the camera is Gerald Griffin, flight director. Credit: NASA.
IN THE MEANTIME, THE REST OF MSC was preparing for Apollo 7’s important flight. Gerry Griffin would have his first job as flight director for this mission, along with Gene Kranz and Glynn Lunney. The three flight directors agreed they were looking forward to working with the crew of Wally Schirra, Donn Eisele and Walt Cunningham. However, during some of the first integrated simulations with the crew, Lunney noticed that Schirra directed some hostility toward the SimSup and that he seemed unwilling to go through several of the training scenarios. The tensions seemed to defuse after Lunney indicated to Schirra that this lack of cooperation might need to be reported to chief astronaut Deke Slayton. Lunney thought that was the end of any problems with the crew. But after the mission launched, Lunney realized he should have seen this as a warning sign.
On Apollo 7’s launch day, October 11, 1968, the stakes were high. It was the first time NASA sent astronauts into space since the Apollo 1 fire twenty-one months prior, and this mission would be a crucial test of the new and improved CM. During its ten-day flight, Apollo 7 would need to prove all the hardware could function properly to enable a mission to the Moon.
Apollo 7 lifts off from Cape Kennedy Launch Complex 34 on October 11, 1968, for the first crewed lunar orbital mission. Credit: NASA/KSC.
Astronauts Wally Schirra (on right), mission commander, and Donn Eisele, Command Module pilot, are seen in the first live television transmission from space. Schirra is holding a sign which reads, “Keep those cards and letters coming in, folks.” Out of view at left is astronaut Walter Cunningham, Lunar Module pilot. Credit: NASA.
It was a hot day at Cape Canaveral when the Saturn IB lifted the crew to
orbit in a perfect launch, a great new beginning for Apollo. The first day, the crew conducted tests on equipment and procedures, with only minor problems. But by the next day, complaints from the crew began about the food, the packed and demanding schedule and the cumbersome waste-management system for bathroom needs. Then, although all the systems were operating well, the crew came down with colds. They soon found that having a stuffed head in weightlessness can be problematic, since nasal passages don’t drain well.
Of course, with public interest in this first crewed Apollo flight running high, the media grabbed the story about the head colds but also soon noticed abrupt, terse exchanges between Apollo 7 and the ground.
There was a request from Mission Control to power up the new TV camera system ahead of schedule to check the circuits. Schirra refused. “You’ve added two burns to this flight schedule, and you’ve added a urine water dump, and we have a new vehicle up here, and I can tell you at this point TV will be delayed without any further discussion until after the rendezvous.”
The Apollo 7 crew after splashdown, arriving aboard the USS Essex. Left to right are astronauts Wally Schirra, Donn Eisele, Walt Cunningham and Dr. Donald E. Stullken, NASA Recovery Team leader from the Manned Spacecraft Center’s (MSC) Landing and Recovery Division. Credit: NASA.
However, later, when it was time for the first live television broadcast from a US spacecraft, viewers around the world were treated to the Walt, Wally and Donn Show, a lively, spirited and happy exchange from inside the CM. The smiling crew displayed hand-lettered cards reading, “From the Apollo Room, High Atop Everything” and, “Keep those cards and letters coming in, folks.” The show was a hit—not to mention a public relations win for NASA—and all seemed well.
Meanwhile, the CSM performed superbly except for some minor problems with the fuel cells. But the griping continued from the crew, with complaints about noisy fans and water puddling from a coolant line, along with more rebuffed requests when ground controllers added or changed a task. In what should have been a triumphant first flight, frustrations ran high both in space and on the ground.
A final breach of protocol came at the end of the mission when the crew didn’t want to wear their helmets for reentry due to their stuffy heads. Finally, in a rare move, Slayton himself radioed up to the astronauts, telling them all other crews donned their helmets for landing and there was no previous experience in landing with them off. After a testy exchange, Slayton finally said, “It’s your neck, and I hope you don’t break it.” Schirra signed off abruptly with, “Thank you, babe.”
The crew landed safely without their helmets. However, they never flew in space again.
Still, this was an essential mission for Apollo, even with a grumpy crew. The flight itself was nearly perfect, circling Earth 163 times. The mission met more objectives than originally planned, the spacecraft performed well and the Walt, Wally and Donn Show would win an Emmy Award. Now it was time to focus on Apollo 8’s daring mission and continue to prepare for an eventual mission to land on the Moon.
NINETEEN SIXTY-EIGHT HAD BEEN A turbulent year so far, for both the US and the rest of the world. Assassins killed Martin Luther King Jr. and Robert Kennedy. The Vietnam War continued to escalate, and details of the bloody Tet Offensive and My Lai Massacre were brought into American living rooms by Walter Cronkite and other reporters on the scene. Protests by antiwar demonstrators, students and counterculture activists resulted in violence at the Democratic National Convention in Chicago, on college campuses and in the streets. There were prison riots and rising drug use. “Don’t trust anyone older than thirty,” said the free-speech movement. Soviet tanks in Czechoslovakia prompted the US to cancel arms treaty negotiations with the USSR. Students protested in Paris. Hundreds of students were killed in Mexico.
Apollo 7’s success provided a brief respite from the horrifying news reports. But then came Apollo 8.
On December 21, Apollo 8 took off atop a Saturn V rocket from Launchpad 39A at Kennedy Space Center. After one and a half orbits around the Earth, the third-stage booster began a four-minute burn to put the spacecraft on a lunar trajectory. Over the next few hours, Anders, Borman and Lovell experienced an unusual sensation that no human had ever encountered before: At first, they could see all the way from Chile to England; then the Earth became an entire sphere; then they watched in wonder as the whole Earth began to get smaller and smaller.
The crew of the Apollo 8 mission, left to right, are James A. Lovell Jr., Command Module pilot; William A. Anders, Lunar Module pilot, and Frank Borman, commander. They are standing beside the Apollo Mission Simulator at the Kennedy Space Center. Credit: NASA.
Apollo 8 coasted to the Moon. During a 2:00 a.m. shift in the Flight Dynamics staff room, Jack Garman and his fellow engineers took bets. In all the Apollo missions so far, the Guidance and Navigation Computer worked on a coordinate system based on the Earth, performing calculations for navigation, gravity and position, all based on Earth’s gravitational influence. But this flight was the first time a spacecraft with humans on board would go far enough away from our world to enter the gravitational sphere of influence of another celestial body: the Moon. Garman wanted to know the exact moment that switch took place. Nothing dramatic would happen, no jolt or noticeable change to the crew, but a shift for the computer and a first for humanity as the Moon’s gravitational force on Apollo 8 became stronger than the Earth’s.
A striking view from the Apollo 8 spacecraft showing nearly the entire Western Hemisphere, from the mouth of the St. Lawrence River, including nearby Newfoundland, extending to Tierra del Fuego at the southern tip of South America. Central America is clearly outlined. Nearly all of South America is covered by clouds, except the high Andes Mountain chain along the west coast. A small portion of the bulge of West Africa shows along the sunset terminator. Credit: NASA.
Since Apollo 8 was a mission full of firsts like this, the flight dynamics team set their consoles to notify them when certain events took place—such as when the translunar injection burn successfully put the spacecraft on course for the Moon and other milestones. An event light on their console would quietly let them know when the shift in gravitational influence happened.
“Now, navigationally, we knew exactly the point the vehicle was actually going to cross this threshold,” Garman said, “but we’re down to a gnat’s hair here, because there’s close to a two-second lag time in telemetry due to how far away the spacecraft was. We’re trying to take bets on exactly when that light is going to come on.”
Fifty-five hours and forty minutes into the flight, when Apollo 8 was 38,759 miles away from the Moon, the light came on. The engineers just stared at it.
“My God,” Garman told his colleagues. “My heavens, it’s real. They’re falling toward the Moon.”
After entering lunar orbit, the Apollo 8 astronauts looked down on rugged terrain never before seen by human eyes. This scene is typical of farside terrain, consisting of craters superimposed on older craters. The view extends about 350 statute miles to the horizon. Credit: NASA.
JOHN PAINTER RETURNED TO THE HOUSTON area for the Christmas holiday and got in touch with his old colleague Howard Kyle. Kyle invited Painter to join him in the Vehicle Systems Staff Support Room in Mission Control during a critical mission event, the lunar orbit insertion burn. If the engines fired successfully, Apollo 8 would become the first crewed spacecraft in lunar orbit. Kyle gave Painter the opportunity to sit at a console and listen on a headset to the Apollo USB voice channel, the system he had worked so hard to document and refine.
The chatter on the communication loop indicated Apollo 8’s precise trajectory was about to send them around the far side of the Moon. If all went well, the SM’s service propulsion system engine would fire just long enough to slow their velocity, allowing the Moon’s gravitational field to capture the spacecraft and put them in lunar orbit. With the crew behind the Moon, no communications were possible during the engine burn. If the maneuver was successful,
Mission Control would regain the signal after thirty-two minutes and thirty-seven seconds. If the engine didn’t fire at all, they would regain the signal in twenty-two minutes; it would also mean Apollo 8 was heading back to Earth. But a variety of engine malfunctions and firing times could result in different signal reacquisition times.
The Apollo 8 photo that has come to be known as “Earthrise,” the first look by human eyes of our home planet from another world. Credit: NASA.
Painter listened as the voice channel became silent as the spacecraft passed behind the Moon, the headset producing the slight hiss of an empty channel. Everyone watched the clock. Twenty-two minutes passed with no signal. After earlier chatter, the voice channel again became silent as everyone waited for the time of reappearance.
More silence. Then, a familiar sound came over the radio channel. It was a descending tone, ending in a unique sound that Painter had heard many times before: wheeeeeeouuu … thunk. It was the sound of the ground’s USB radio receiver correcting for the Doppler shift of the incoming radio signal and then locking onto that signal. Then came a voice, Lovell’s simple call, “Houston, Apollo 8. Burn complete.” From Mission Control, Capcom Jerry Carr replied, “Apollo 8, this is Houston.” The room broke into cheers, and Painter’s eyes got a little wet.
DURING THE FIRST THREE ORBITS, APOLLO 8’s astronauts kept the spacecraft’s windows pointing down toward the Moon while they hurriedly filmed and photographed the craters and mountains below. One of their main tasks was reconnaissance for the future Apollo landings.
On the fourth swing around from the Moon’s backside, Borman rolled the spacecraft to a different orientation, pointing the windows toward the horizon to get a navigational fix. A few minutes later, he spotted a blue-and-white object coming over the horizon.
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