Jerry Woodfill, an engineer who worked diligently behind the scenes during NASA’s Apollo program, has passed away at age 79. Jerry was still employed by the Johnson Space Center (JSC) at the time of his death, working there for over 57 years. Most notably, Jerry worked as the lead engineer behind the Caution and Warning System on the Apollo spacecraft, which alerted astronauts to issues such as Apollo 11’s computer problems during the first Moon landing, and the explosion of Apollo 13’s oxygen tanks.
While continuing his work as an engineer at JSC, Jerry’s infectious enthusiasm for spaceflight led him to also be part of NASA’s public and educational outreach, where he spearheaded programs for children, teachers and adults about science and space flight. He routinely gave over 40 lectures a year, both in person and online to listeners around the world. His unique sense of humor and sometimes unabashed showmanship could hold even the shortest of young attention spans. Jerry usually had his audiences either in stitches or fully captivated by his stories.
A water level view of the Apollo 13 recovery operations in the South Pacific Ocean. Credit: NASA
50 years ago today, on April 17, 1970, the crew of Apollo 13 came home. Safely. Successfully.
The world breathed a collective sigh of relief as they watched NASA turn a disaster into one of the most dramatic happy-endings ever.
The flight of Apollo 13 was unlike any other Apollo mission,
and the final hours of the flight – preparing for and implementing the reentry
to Earth – was unlike any other, as well.
Overall view showing some of the activity in the Mission Operations Control Room during the final 24 hours of the Apollo 13 mission. From left to right are Shift 4 Flight Director Glynn Lunney, Shift 2 Flight Director Gerald Griffin, Astronaut and Apollo Spacecraft Program Manager James McDivitt, Director of Flight Crew Operations Deke Slayton and Shift 1 Flight Surgeon Dr. Willard Hawkins. Credit: NASA.
Following the explosion of an oxygen tank in Apollo 13’s
Service Module on April 13, 1970, approximately 56 hours into the mission, the
situation was bleak. With the Command Module (CM) without any power, the Lunar
Module (LM) was activated as a life boat to sustain the crew. The task ahead –
to save the spacecraft and the crew, and get them home again — would require an
incredible amount of innovation by both the Apollo 13 astronauts and the
engineers back on Earth.
The explosion caused the loss of the main source for oxygen,
water, and most importantly, electrical power for the CM. With only 15 minutes
of power left in the CM, astronaut Jack Swigert powered down the CM while Jim
Lovell and Fred Haise got the LM up and running.
For engineers on the ground, one of the biggest concerns was
maintaining enough electrical power in the LM and then creating enough power in
the CM to power it back up again for reentry to Earth.
The crew of Apollo 13 after landing safely. Credit: NASA.
Apollo 13 was supposed to be the third mission to land humans
on the Moon. But on the night of April 13th, 1970, an oxygen tank in Apollo
13’s Service Module exploded. And so began the most perilous but eventually
triumphant situation ever encountered in human spaceflight.
The explosion crippled the Apollo 13 Command Module and
endangered the lives of astronauts Jim Lovell, Fred Haise, and Jack Swigert.
During the four days that followed, thousands of people back on Earth worked
around the clock to ensure the astronauts’ safe return.
We’re in uncharted territory as the world faces the Coronavirus (COVID-19) pandemic. While the medical community is on the front lines of dealing with this, as well as others who provide critical services in our communities, the best thing many of us can do is to stay home (and wash our hands).
If you’re looking for ways to keep occupied, keep your kids in learning-mode while school is canceled, and expand your horizons — all at the same time — luckily there are lots of space and astronomy-related activities you can do at home and online. We’ve compiled a few of our favorites, including this first one, one that just became available yesterday.
Apollo 13 images via NASA. Montage by Judy Schmidt.
Now that we’ve celebrated the 45th anniversary of Apollo 13 and completed our series “13 MORE Things That Saved Apollo 13” and we want to see how well you’ve been paying attention! Here are 13 questions about the mission taken from this series as well as our original “13 Things” series that was published in 2010. The questions follow and the answers are listed below. Let us know how you do!
Apollo 13 Crew
1. Name the three astronauts on Apollo 13 and their roles/official titles in the mission.
2. What caused only 12 men to walk on the Moon instead of 14?
3. Why was a newspaper reporter’s training helpful in saving Apollo 13?
4. Who was credited in the Apollo 13 movie with the statement “Failure Is Not an Option” but never actually made that statement.
5. What Apollo astronaut’s statue is in the Halls of Congress?
6. Blackout on reentry lasted approximately 87 seconds longer than expected. Explain some theories on why this was so.
7. Explain why you think the hatch would not seal/close property when it worked correctly at the time of jettisoning the lander in preparation for reentry?
8. What everyday item(s) assisted Apollo 13 in finding the way back to Earth?
9. What Hollywood movie predicted 7 facets of Apollo 13’s rescue?
10. Who is the only man to have orbited the Moon on two missions without landing on the Moon?
11. Which astronaut on Apollo 13 became ill during the flight?
12. Apollo 13 marked the first time the 3rd stage of the Saturn V rocket did not either burn up in Earth’s atmosphere or end up in a heliocentric orbit. Where did it land?
13. What was the duration of the Apollo 13 Mission?
The crew of Apollo 13 after they splashed down safely. Credit: NASA
Answers:
1. James A. Lovell, Jr. Commander, John L. Swigert, Jr., Command Module Pilot, Fred W. Haise, Jr., Lunar Module Pilot.
2. Even though there were 7 Apollo missions that were supposed to land on the Moon with 2 astronauts walking on the Moon in each mission, , Apollo 13 never landed because of the accident. Read more about the explosion and why the timing of the accident was important to the crew’s survival here.
Fred Haise, in 1966. Credit: NASA
3. Fred Haise had been a newspaper stringer for a small newspaper in Mississippi when he was younger, taking notes and editing them for his local Mississippi paper’s stories. Utmost among reporters is accuracy in quoting sources. The transmitted words from Mission Control had to be flawlessly transcribed if the crew was to survive, and Haise did an amazing job. Read more about it in the article in the original “13 Things,” Charlie Duke’s Measles.
The view in Mission Control after Apollo 13 landed safely. Gene Kranz is featured on the right. Credit: NASA
4. In the movie Apollo 13, Gene Kranz says the line, “Failure is not an option!” Even though Kranz never actually said those words during the “real” Apollo 13 mission, he liked the phrase so much that he used it for his autobiography. Who said it? Jerry Bostick, who was the Retrofire Officer and Flight Dynamics Officer in Mission Control during the Mercury, Gemini, Apollo and Skylab programs, said it during interviews for the Apollo 13 movie. Read more about the phrase and why they used it the movie here.
The statue of John L. “Jack” Swigert, Jr. is located in Emancipation Hall at the U.S. Capitol Visitor Center.
5. A statue of Jack Swigert is located in Emancipation Hall at the U.S. Capitol Visitor Center. Swigert was elected to Colorado’s Sixth Congressional District in 1982, but he died on December 27, 1982, before taking office. Read more about the Swigert and the statue here. Read more about the traits that made Swigert such a valuable crew member on Apollo 13 in “Charlie Duke’s Measles.”
6. The longer than expected blackout period has never been fully explained, but several explanations have been offered. They include: the spacecraft coming in on a shallower trajectory that would result in a longer period in the upper atmosphere where there was less deceleration of the spacecraft and the communication signal skipping like a stone over layers of the upper atmosphere because of the shallow entry angle. Read more about the ‘shallow’ reentry and the communications blackout in our article here.
7. No one has fully explained why the hatch wouldn’t close immediately after the accident while it worked fine at reentry. It may have been because the two spacecraft (Command Module and Lunar Module) were skewed or twisted right after the explosion, but the position normalized later. Read more at the original series part 2, “The Hatch That Wouldn’t Close,” and part 8, “The Command Module Wasn’t Severed.”
8. The Apollo 13 crew used things like watches, flashlights, pencils, pens and of course duct tape to help save the mission. Read more about them at “‘MacGyvering’ with Everyday Items” and “Duct Tape.”
9. The 1969 movie Marooned depicts three astronauts who survive an accident in space, but their lives hang in the balance as the people in Mission Control at NASA work night and day to figure out a way to bring the spacefarers home safely. Read how the movie inspired a NASA engineer to consider options for recharging the LM batteries in the original series part 11, “A Hollywood Movie.”
Apollo 13 commander Lovell with a model Lunar module. Image credit: NASA
10. Jim Lovell took 2 trips to the Moon but never landed. He was on Apollo 8, which became the first human mission to orbit the Moon in 1968 and on Apollo 13, which didn’t land on the Moon because of the oxygen tank explosion in the Service Module.
11. Fred Haise got a kidney infection during the mission, possibly from not drinking enough water. Water was one of the resources that was scarce because of the inoperable fuel cells, which normally creates water as a byproduct of producing electrical power. Learn more about the Apollo era fuel cell at the Smithsonian Air & Space Museum.
The seismic station at the Apollo 12 site. The seismometer monitors the level of ground motion to detect arriving seismic waves. The instrument (left) is protected by metal foil against the varying temperatures on the lunar surface that produce large thermal stresses . Credit: NASA
12. The Saturn V 3rd stage (S-IVB) was part of a science experiment and was crashed into the Moon. The Apollo 12 mission had left a seismometer on the Moon, and an impact could produce seismic waves that could be registered for hours on the seismometer. This would help scientist to better understand the structure of the Moon’s deep interior. Find out more about the experiment and the communications problem caused by the 3rd stage at our article, “Detuning the Saturn V’s 3rd Stage Radio.”
Our thanks, once again, to NASA engineer Jerry Woodfill who originally came up with the ideas for the “13 Things” and “13 MORE Things That Saved Apollo 13.”
NASA engineer Jerry Woodfill at a presentation to students. Image courtesy Jerry Woodfill.
To celebrate the 45th anniversary of the Apollo 13 mission, Universe Today has been featuring “13 MORE Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill. Today, we let Jerry have the final word as he talks about a different aspect of the Apollo 13 mission.
Written By Jerry Woodfill:
I hesitated to include this among the “Things That Saved Apollo 13” because it is sort of intangible, i.e., not related to actual hardware, software, mission operations, and all things STEM. Nevertheless, in my mind, it is, perhaps, most responsible for the ultimate success of the rescue. I think it might override all the original “13 Things” as well as the “13 More Things that saved Apollo 13.”
Adding it came to me on New Year’s Eve of 2014. For a number of years, Apollo Flight Director Gene Kranz has presented a wonderful motivational program entitled and based on this concept, this motto, this creed — that failure is not an option. Five years ago, I borrowed the title for annual programs presented to high school and college students visiting the Johnson Space Center, such as in the picture above and below.
Jerry Woodfill speaking to students. Image via the NASA National Community College Aerospace Scholars Website.
Universe Today writer Nancy Atkinson discussed in part 11 the origin of the saying “Failure is Not an Option,” which actually came from one of the “Trench” team members, Jerry Bostick.
Of course, there are those who consider the phrase “pie in the sky,” altogether “over-the-top” and “Pollyanna.” They assert that such is unrealistic when faced with obviously insurmountable challenges. For me, the best argument to counter that view came years ago from comments I’ve found on the internet. Below are a couple of paraphrased examples:
“Well… Apollo 13 has become my role model, my support, my comfort, and my favorite movie at 3 AM when I can’t sleep because I’m so overwhelmed with my own life. This is about how I use the movie as a crutch to get me through the day. This is about how Apollo 13 keeps me sane in an insane time!”
“They say that Apollo 13 was a Successful Failure because of all they learned from the experience. I’m hoping that my experience with cancer will also be a Successful Failure. The doctor has already told us that my dad won’t be cured, and any treatments we do won’t change that. So I already know that I’m going to be a failure. Nothing I do can save my father’s life. But maybe I can learn and grow. Just maybe my dad and I can have some more good times together. Maybe we can have some fun and overcome some challenges on this journey. Then I’d say it would be a successful failure for sure. Sometimes, I’m surprised at how my life seems to parallel the hardships the astronauts had to endure. I find myself doing things for my dad that I never imagined I would have to do.”
In like fashion, the heroism of Jim Lovell, Fred Haise, and Jack Swigert along with the resolve, perseverance, and herculean efforts of all involved would always be revered. “Failure Is Not an Option” is not naïve whatsoever. It is a guiding principle for whatever challenge we face.
I’ve also received emails, like the one below from people who have come across my off-the-job internet site:
Dear Mr. Woodfill:
I just watched the movie Apollo 13 and started researching the quote “failure is not an option”. In doing so I came across an article you had written, and I wanted to thank you for it.
I appreciated everything you wrote, but I was especially touched by the following: “I have to make sure that I do my best to make every day with my dad as wonderful as possible, that the end of his life is as good as it can be, and we learn something new every day we are together. I also need to remember that no matter how bad things get, I love my daddy and he loves me. If I just remember that… I can’t fail.”
Finding your article was such a blessing because today they just told me my father would have to go on hospice, and I have been praying to God for strength and peace for my father and for myself. After all, what could I possibly say or do that could help him? But after I read this I knew. I just have to love him. So thank you for that.
You wrote the article many years ago, and I know chances are small that you will ever receive this email. But I just wanted you to know how much peace I received from what you had written. Because, as you said, no matter how bad things get, if I just love him, I can’t fail.
Bless you for reminding me of that.
Sandra
+ + + + +
Finally, Nancy asked me to explain how the phrase “Failure Is Not an Option” affected me. So how did that tagline affect me? Experiencing the “13 Things” and “the 13 More Things, at first in real time, and later in 100s of hours of reflection wholly changed the course of my life. I simply could not ignore the overwhelming evidence of so many things that saved Apollo 13 being fortuitous. In both series, I’ve done my best to “de-spiritualize” the accounts, knowing this series is a secular assessment. Actually, the genesis of every one of the now “26 things,” for me, was altogether providence or answered prayer. How this ensued is recorded on my off-the-job website if you are interested, as Paul Harvey used to say, in “the rest of the story.”
But I wanted to reach out to a much broader audience by sharing a factual secular account. I’m grateful to Nancy and “Universe Today” for making that possible.
In an off-hand way, many who have followed the series may have concluded what I discovered – that a person or power above had intervened as another of “the things that saved Apollo 13.” So I am always encouraged by the tagline “failure is not an option.” Now, it is, for me, another way of saying what I discovered through Apollo 13’s rescue that “all things work together for good,” as the above email says.
Thank you!
Sincerely,
Jerry Woodfill
Jerry Woodfill with students from the Community College Aerospace Scholars, with the ‘Failure Is Not an Option’ pledge in the background. Image courtesy Jerry Woodfill.
Apollo astronaut photo of a SNAP-27 RTG on the Moon. Credit: NASA.
To celebrate the 45th anniversary of the Apollo 13 mission, Universe Today is featuring “13 MORE Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.
For our final installment of this series of “13 More Things That Saved Apollo 13,” we’ll look at an event that has not been widely addressed, but it may have been one of the most crucial scenarios which might have ended in disaster and death for the crew in the final minutes of the rescue.
It starts with an atomic electrical power generator called SNAP-27.
These devises enabled the Apollo Lunar Surface Experiment Package (ALSEP) to operate on the Moon for years after astronauts returned to Earth. They were deployed on Apollo 12, 14, 15, 16 and 17 and included seismometers, and devices to detect lunar dust and charged particles in the lunar environment.
SNAP stands for Systems Nuclear Auxiliary Power and its fuel was plutonium-238 (Pu-238). It was a type of Radioisotope Thermoelectric Generator (RTG) that provides electrical power for spacecraft by converting the heat generated by the decay of plutonium-238 fuel into electricity. Approximately 8 lbs of plutonium was used for each mission and it was it was transported to the Moon in a thermally insulated cask attached to the side of the Lunar Module.
“The cask was so strong and impervious that firing the container with a cannon into a solid brick wall would not break it,” said NASA engineer Jerry Woodfill.
Unfortunately, Woodfill added, as the political climate for anything atomic has grown acrimonious, the application of atomic energy to space exploration has been thwarted.
“Despite a remarkable atomic safety record, a small but powerful political coalition has successfully opposed such harmless devices as NASA’s Apollo SNAP-27 generator,” said Woodfill. “The scare-factor attributed to NASA’s Apollo atomic power generator was based on the threat of a launch pad explosion or exaggerated claims that an accident would contaminate Earth’s atmosphere and ultimately bring death to many. It is amazing that such groups can ignore obvious day-to-day deaths in automobiles yet alarm the public with false atomic threats.”
Apollo 13 Commander Jim Lovell carrying a plutonium battery and scientific equipment during training. Credit: NASA.
Woodfill said that the opposition to RTGs has been most unfortunate for the sake of human and robotic exploration of the solar system.
“The limitation of traditional rocket fuels handicaps improvement in propulsion,” he said, “and for the past five decades, little progress has been made in rocket engine specific impulse improvement known as the ISP.”
Additionally, for several years NASA has been facing a shortage of RTGs for powering robotic spacecraft limiting the scope and lifetime of missions going to the far reaches of our Solar System.
For Apollo 13, the SNAP-27 device should have ended up staying on the Moon, but of course, the lander did not land so it, along with the atomic generator, was going to reenter Earth’s atmosphere and end up somewhere on our planet.
It wasn’t long after the accident on Apollo 13 that NASA was contacted by the Atomic Energy Commission (AEC) about where the LM would be reentering and burning up in Earth’s atmosphere.
However, as Apollo 13 approached Earth, their flight path kept deteriorating, despite the crew’s efforts. As we discussed in Part 9 of this series about the potentially fatal gimbal lock, without the Command Modules thrusters and computer navigation system to steer, only the lander’s were available, and manually flying the crippled Apollo 13 spacecraft stack and keeping it on the right trajectory was a huge challenge.
Woodfill said that any ‘tinkering’ with the reentry geometry was altogether ill-advised considering how very ‘iffy” the angle and entry path had become, but AEC officials were pressuring the retro officers about the orientation required for the LM’s reentry to put it into a deep trench in the Pacific Ocean.
Woodfill said that from his perspective of decades of study about the mission, the need to “deep-six” the SNAP-27 generator was almost responsible for having the Apollo 13 rescue end in tragedy. There was confusion among those in Mission Control as well as the crew about the orientation the spacecraft at reentry. However, Woodfill said, an inadvertent ‘mistake’ by Lovell may have actually saved the crew.
“There was a significant debate between the two most knowledgeable retro officers about jettisoning of the lunar lander,” he said. “So uncertain was the scenario of positioning the command ship for LM jettison that the men held exactly opposite views of the result of selecting the position wanted by the AEC scientists. Added to the peril was Lovell’s brush with ‘running the ship aground’, i.e., into gimbal-lock trying to please the AEC.”
A 2009 research paper for AIAA adds insight into the danger of these moments prior to LM jettison and Lovell’s error. “Attempts to perform rapid analysis in a high pressure, time critical spacecraft emergency can lead to errors in analysis and faulty conclusions,” the paper reads. “For example, the spacecraft was maneuvered to the wrong LM/CM separation attitude, ~45 degrees on the north side of the CM ground track rather than the desired 45 degrees on the south side of the CM ground track. This attitude was close to CM IMU gimbal lock and complicated manual piloting.”
Mission transcripts reveal the confusion and the difficulty the crew faced. As Lovell was trying to maneuver the stack into the correct orientation for LM jettison he radioed:
Lovell: We’re having trouble maneuvering, Joe, without getting it in gimbal lock… You picked a lousy attitude, though, to separate.
Capcom: Well, we apologize. Just take your time. Jim, we’ve got time now.
Lovell continued to struggle as the ship continually approached gimbal lock and he questioned the procedure:
Lovell: Houston, why can’t I stay in PGNS ATT HOLD for the LM attitude hold?
Capcom: Stand by on that, Jim.
Lovell: I want to get way over here, Joe, to prevent going into gimbal lock. I have the yaw at about – I’d say about almost 50 degrees.
Capcom: Roger that. Just stay out of gimbal lock and that 45-degree isn’t critical – the out of plane, that is.
Nonetheless, an Apollo 13 post-mission report reveals that shortly before LM jettison the Retro Officer Chuck Deiterich advised the Flight Director that the LM was not in the correct orientation for separation. “The telemetry indicated that we were yawed 45 degrees North instead of 45 degree South,” the report says, so the ship was 90 degrees out of yaw attitude prior to LM jettison.
However, the LM closeout was underway, and there was no chance to use the thrusters to change attitude. The report continues, “No correction action was taken, because the separation was a minimum of 4,000 feet at entry interface, and more likely was going to be 8000 feet or greater. Therefore, no attempt was made to change the attitude.”
“Because the LM’s guidance computer was maintaining the jettison attitude, the crew could no longer steer the assemblage until the LM release,” explained Woodfill. “And then a terribly threatening event arose. In order to preserve the desired attitude to assure that the SNAP-27 plutonium landed in the ocean, the LM’s computer was moving the command ship’s platform into gimbal lock. It was too late to re-enter the LM. The time to unlatch the hatches would be too great.”
But despite the likely loss of control, somehow the LM was jettisoned just prior to the Command Module reaching gimbal lock.
“Had not, it was later discovered, Jim Lovell actually have mistakenly placed the attitude 90 degrees from the desired jettison position, a potentially fatal gimbal lock would have happened,” Woodfill said. “It was as though despite the disagreement between the retro experts and the resulting confusion between Mission Control and the crew, and then Lovell’s error, neither of the miscues of the entire scenario resulted in the dreaded gimbal-lock. Plus, the SNAP-27 ended up in an optimum location in the Pacific Ocean. Indeed, two mistakes made a right. The entry capsule’s guidance platform became stable and ready for reentry.”
However, Deiterich told Universe Today that with respect to the LM jett attitude, the landing point was not greatly affected by north or south. But to assure maximum separation during entry, the southerly direction was actually opposite the northerly direction the crew would fly.
“When I realized they were closing out, I told Kranz we would buy the current attitude,” Deiterich said via email. “The inplane separation velocity was enough to assure reasonable down range separation. We were just being thorough. Knowing is why we accepted the jettison attitude. I remembered the A10 Ascent stage jett and how the pressure between the CM and ASC pushed the ASC away so I picked this as a way to jett the LM on A13.”
Both during the mission and the crew debriefing the puzzling topic of that SNAP-27 disposal caused confusion. Days later during the debriefing, the crew seemed at a loss to understand what was going on with regard to ground control’s insistence on assuming such a particular jettison orientation for the lunar module. Somehow, they didn’t seem aware of the issues with the SNAP-27 atomic generator, an issue that likely would not threaten Earth but in every way threaten the lives of Lovell, Swigert and Haise.
“We were very close to gimbal lock,” Lovell said in the mission debrief. “I questioned whether the LM SEP attitude was that critical. Was it so critical to be at that attitude, or would it have been better to stay away from gimbal lock in the CM?”
Lovell was worried that they didn’t have any backup help of navigating — the Body Mounted Attitude Gyros, or BMAGs. “We didn’t have the BMAGs powered up,” Lovell said in the debrief. “If we had gone into gimbal lock, we would have had to start from scratch again.”
Deiterich agreed, especially since the crew was pressed for time as time for reentry was rapidly approaching. “Maneuvering the LM with the CSM attached was not easy,” Deitrich said via email, “thus Jim tried to keep any maneuvering out of plane to a minimum, once there he was reluctant to move away and also the whole process was brand new and time could then become a factor.”
The crew of Apollo 13 after they splashed down safely. Credit: NASA
Woodfill said the entire team in Mission Control helped save the crew – the EECOM (Emergency, Environmental, and Consumables Management) and the lander’s TELMU (Telemetry, Electrical, EVA Mobility Unit Officer) dealing with the spacecraft environmental and power systems, and the ‘Trench’ team of the FIDO flight dynamics officer who was responsible for the trajectory, the GUIDO guidance and navigation officer who was charged with assessing the crafts’ ability to steer itself under astronaut control, and finally, the RETRO whose responsibility was entering Earth’s atmosphere via retro-rocket firing.
“Considering Apollo 13’s myriad of challenges, it would be a toss-up between the groups if a vote were taken akin to voting for the outstanding “player” in a Monday Night Football game,” he said. “But there is no doubt with regard to the final minutes of the contest who would win the vote. It would be the latter group dealing with guidance and reentry. This is especially so considering the number of times the group thwarted loss of guidance. Without them, Apollo 13 would have lost the game to the formidable adversary gimbal-lock.”
And what happened to Apollo 13’s SNAP-27? In the book “Thirteen: The Flight that Failed”, Henry S.F. Cooper said that the plutonium apparently survived reentry and landed in the Tonga Trench south of Fiji in the Pacific Ocean, approximately 6-9 kilometers underwater. It exact location is unknown but monitoring of the areas has shown that no radiation escaped.
Apollo 13 images via NASA. Montage by Judy Schmidt.
A look at the Mission Operations Control Center (MOCR) or Mission Control during the Apollo era. In this image, 2 is the Retrofire officer, 3 is the Flight Dynamics Officer and 4 is the Guidance Officer. Credit: NASA.
To celebrate the 45th anniversary of the Apollo 13 mission, Universe Today is featuring “13 MORE Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.
In the original Mission Operations Control Room (MOCR) at the Manned Spacecraft Center in Houston, a group of NASA flight controllers sat in the front row of the consoles, aligned nearest to the enormous front wall displays of the MOCR, or Mission Control. They sat in a ‘trench-like’ lower level with respect to the remaining flight controllers and this group came to be known as “The Trench.”
“The teamwork of the Apollo 13 band of Trench ‘brothers’ coordinating navigational challenges in a fashion that was never accomplished before or after in the annals of lunar flight was certainly one of the additional things that saved Apollo 13,” said NASA engineer Jerry Woodfill. “Failure to reach a consensus quickly in performance of the restoration of free return trajectory, the PC+2 and other crucial ‘burns’ would have been detrimental to rescue.”
Overall view showing some of the activity in the Mission Operations Control Room during the final 24 hours of the Apollo 13 mission. From left to right are Shift 4 Flight Director Glynn Lunney, Shift 2 Flight Director Gerald Griffin, Astronaut and Apollo Spacecraft Program Manager James McDivitt, Director of Flight Crew Operations Deke Slayton and Shift 1 Flight Surgeon Dr. Willard Hawkins. Credit: NASA.
Woodfill said that like the Parachute Infantry Regiment described in Stephen E. Ambrose’s popular book and subsequent mini-series “Band of Brothers” – which told of the teamwork and perils of combat during World War II — the men of The Trench served like a platoon of soldiers defending Apollo 13.
A plaque from the three Apollo 13 astronauts thanking the mission support teams. Note the panels of the caution and warning system above the signatures. "That was my system," said Jerry Woodfill. "The alarm system personified what the team’s role was providing caution, warning, and assistance for the crew’s safety." Image Courtesy Jerry Woodfill.
To celebrate the 45th anniversary of the Apollo 13 mission, Universe Today is featuring “13 MORE Things That Saved Apollo 13,” discussing different turning points of the mission with NASA engineer Jerry Woodfill.
The air to ground transcript from the time of the explosion on Apollo 13 demonstrates the confusion of what was happening:
Jim Lovell: Houston, we’ve had a problem. We’ve had a MAIN B BUS undervolt.
Capcom: Roger. MAIN B undervolt. Okay, stand by, 13. We’re looking at it.
Fred Haise: Okay. Right now, Houston, the voltage is – is looking good. And we had a pretty large bang associated with the Caution and Warning there.
Lovell then started to name all the Caution and Warning lights that were illuminating, including the Guidance and Navigation light, a computer restart, and indicators that there might be a problem with the oxygen and helium tanks.
The Apollo spacecraft Caution and Warning System had one intended function: alert the astronauts and Mission Control to a potential system failure. Plainly put, the Caution and Warning System allowed the spacecraft to tell the story of what was going wrong.
Location of Caution And Warning System lights in the Command Module. Credit: Project Apollo.
In all our discussions so far with NASA engineer Jerry Woodfill, we’re finally letting him talk about the system he was responsible for: the Caution and Warning System (C&WS).
Jerry Woodfill working in the Apollo Mission Evaluation Room. Credit: Jerry Woodfill.Woodfill’s role in the Apollo program was unique in the sense that he held the position and responsibility of Apollo Spacecraft Warning System Engineer. He was responsible for fixing, redesigning, and analyzing warning system performance during testing and early flights. During Apollo 11 and Apollo 13 he was responsible for monitoring the C&WS at his station adjacent to Apollo Mission Control in the engineering Mission Evaluation Room.
Of the image above of the plaque from the Apollo 13 astronauts thanking the mission support teams, Woodfill said, “That was my system. The alarm system personified what the team’s role was providing caution, warning, and assistance for the crew’s safety.”
From an official NASA report on the Apollo spacecraft systems:
“Critical conditions of most spacecraft systems are monitored by a caution and warning system. A malfunction or out-of-tolerance condition results in illumination of a status light that identifies the abnormality. It also activates the master alarm circuit, which illuminates two master alarm lights on the MDS and one in the lower equipment bay and sends an alarm tone to the astronauts’ headsets. The master alarm light and tone continue until a crewman resets the master alarm circuit. This can be done before the crewmen deal with the problem indicated. The caution and warning system also contains equipment to sense its own malfunctions.”
One of Woodfill’s responsibilities was to enter into the Apollo 13 Crew’s Operational Checklist when ”nuisance alarms” might be expected as a result of momentary switching modes. But mainly, he was responsible for setting the thresholds for when the alarms would be activated. The myriad of alarms sounding for Apollo 13 made it obvious that something serious was happening.
“The first alert that Apollo 13 was direly threatened came from the Caution and Warning system’s Master Alarm issued as a result of a Main Bus B under-voltage,” explained Woodfill. “It was because the warning system’s threshold for low voltage was established that the crew and mission control had an instant awareness of the dire situation. This saved valuable time in analyzing the source of Apollo 13’s malfunction.”
Likewise, as we discussed in Part 5 of this series, it was the setting of the threshold of the CO2 caution light ringing a Master Alarm which alerted the crew to the need for changing out the lithium hydroxide canisters to filter out the danger carbon dioxide that was accumulating in the Lunar Module.
“The component caution CO2 light’s illumination, while backed-up by a gauge, nevertheless, made the need for a solution all the more apparent,” said Woodfill.
And, of course, when the Oxygen Tank 2 Quantity sensor failed, a Master Alarm sounded from the Caution and Warning System as an alert, along with the quantity gauge reading, that trouble shooting should be undertaken.
Woodfill noted that because multiple inputs from the tanks were “OR-gated” (electronic logic system disjunction) into the alarm system, the actual explosion of Oxygen Tank 2 did not set off the Master Alarm, via the oxygen tank inputs to the C&WS, but rather the resulting secondary sensing by the C&WS of the Main Bus B undervolt input which did. But he does believe the failure of the Tank 2 sensor did earlier set off the Master Alarm to initiate the trouble shooting, not being masked by “OR-gating” of other items.
Apollo 1 astronauts (from left) Virgil “Gus” Grissom, Edward White and Roger Chaffee stand near Cape Kennedy’s Launch Pad 34 during training. Credit: NASA
In our original series of “13 Things That Saved Apollo 13” Woodfill explained how the Apollo 1 fire – as tragic as it was – contributed to the success of future Apollo flights and the saving of Apollo 13 by the design improvements in spacecraft components and systems.
“This resulted in the much improved, safer, more reliable Apollo Command Module,” said Woodfill.
Woodfill said the C&WS additionally helped — both before and after the fire — to reveal what in the manufacture of the poorly made initial Block One ill-fated Spacecraft 012 that contributed to the fire which cost the lives of the Apollo 1 crew in January of 1967.
“The Caution and Warning System revealed a myriad of glitches, flaws, discrepancy reports, squawks, oversights and shortcomings,” Woodfill said. “Yet, the warning system, in doing its job, led to design improvements in the next series of Apollo craft which included Apollo 13. Though compromised by a damaged O2 tank, Apollo 13 had numerous features added as a result of the terrible Spacecraft 012 fire.”
Woodfill’s part in improving the system was key. Both the Command and Lunar Module’s C&WS were improved following the fire, and were thoroughly reviewed to assure all systems were safely upgraded to avoid the kind of failure which killed the Apollo 1 crew. These improvements in the Lunar Module’s C&WS are listed in the Apollo Experience Report Woodfill co-authored as the Warning System Engineer, which can be read here.
“Had not the Caution and Warning System helped alert NASA and the contractor team to how badly the original command ships were made, likely Apollo 13 would have not survived the oxygen tank explosion,” said Woodfill.
Apollo 13 images via NASA. Montage by Judy Schmidt.
