15: Apollo 13

Apollo 13 opens with a little bit of history on the Apollo space program. It starts with footage from the Apollo 1 mission, during a pre-launch test on January 27th, 1967. So right away, the movie starts off with a fact: this actually happened. NASA astronauts Virgil “Gus” Grissom, Edward White and Roger Chaffee were killed in a cabin fire during a pre-flight check.

What the movie doesn’t mention, though, is technically this happened on AS-204, or Apollo-Saturn 204. Apollo being the name of NASA’s space program, and Saturn being the name of the rocket that would carry the Apollo spacecraft into space. At the time, NASA’s Apollo missions were named sequentially, and they had three other missions, AS-201, AS-202 and AS-203, currently being worked on when the three astronauts were killed so unexpectedly. The widows of the three astronauts asked NASA to retire the mission–to not fly another AS-204 mission–in honor of their husbands. NASA agreed, and went one step further.

Even though it was AS-204, the three astronauts had nicknamed it Apollo 1 since it AS-201, 202 and 203 weren’t manned–AS-204 was the first manned mission being worked on.

In April of 1967, NASA’s Associate Administrator for Manned Space Flight, Dr. George E. Mueller, announced that, in remembrance of Grissom, White and Chaffee, what was formerly AS-204 would be known for the rest of history as Apollo 1. The other missions currently in the works wouldn’t be renamed, and instead NASA would never have an Apollo 2 or 3. The next manned spacecraft, a Saturn V rocket, would be known as Apollo 4.

So NASA’s Apollo space program began with a failure at the cost of three human lives. It was a testament to the dangers of trying to get to space.

The world soon forgot this failure, though, and the movie fast forwards to July 20th, 1969, when Apollo 11, manned by Neil Armstrong, Buzz Aldrin and Michael Collins, made history.

And that’s where we first see Jim Lovell, played by Tom Hanks, Jack Swigert, played by Kevin Bacon, Ken Mattingly, played by Gary Sinise, and Fred Haise, played by Bill Paxton. The astronauts are at a party in Houston, Texas, watching on TV, along with the rest of the world, as Neil walks on the moon. An estimated 600,000,000 people watched Neil become the first human to walk on the moon in 1969, which is incredible considering the population estimates from the U.S. Census Bureau for 1969 lists the United States population at about 202,000,000 people–and obviously not every person in the United States had a TV at the time. This was perhaps one of the first huge events that unified the world. Neil Armstrong may have been an American walking on the moon, but it meant something to the entire world.

In the movie, after the party, Tom Hanks’ version of Jim Lovell says he “wants to go back” and afterward in NASA, there’s other dignitaries who ask when he’s going to go back to the moon again. Although the movie doesn’t really focus on this, they’re referring to Jim Lovell’s previous trip into space. He was one of three men aboard the Apollo 8 mission, which launched its six-day mission around the moon on December 21st, 1968. They never landed on the moon, but they were the first humans to ever orbit the moon.

In fact, it was on this mission that one of Jim’s colleagues, William Anders, took Earthrise, the first color photograph of the planet Earth from near the Moon. It’s a photograph that would go on to become one of the most popular photographs in history. You can still see it online, as well as video taken from the Apollo 8 mission and even hear the conversation between Jim Lovell, mission commander Frank Borman and William Anders as he’s taking the photo.

Another pivotal point in the movie happens when Jim Lovell gets bumped up from Apollo 14, which he was scheduled to command, to Apollo 13. Tom Hanks hugs his wife, Marilyn, who’s played by Kathleen Quinlan in the film, as he explains the news. As he says it in the movie, Al Shepard’s ear infection has flared up, and as a result he’s bumped up to Apollo 13.

In truth, that’s not really what happened. NASA’s Director of Flight Crew Operations, Deke Slayton, who’s played by Chris Ellis in the movie, was in charge of making recommendations for which astronauts would go on each mission. The primary crew for Apollo 13 was officially L. Gordon Cooper as Commander, along with Donn Eisele as Command Module Pilot and Edgar Mitchell as Lunar Module Pilot. But Deke wasn’t a fan of Cooper, mostly because Cooper didn’t seem to like training.

And apparently that’s something NASA takes seriously for astronauts.

So Deke passed over Cooper, and for Apollo 13 he recommended the backup crew with Alan Shepard as commander of the mission. Shepard’s crew included Stuart Roosa as Command Module Pilot along with Edgar Mitchell again as Lunar Module Pilot. For the first time ever, Deke Slayton’s bosses at NASA rejected his recommendation. It seems, they thought, that Alan Shepard, who was a former rear admiral in the U.S. Navy before his time as an astronaut, needed more training—he wasn’t quite ready to command his own mission yet.

So it wasn’t really an ear infection, as the movie claims. Instead, NASA swapped Shepard’s crew with Lovell’s crew. It would be Jim Lovell, or Tom Hanks in the movie, as Commander along with Ken Mattingly, Gary Sinise in the film, as the Command Module Pilot and Fred Haise, Bill Paxton in the movie, as Lunar Module Pilot.

And as with everything at NASA, there were always backups. In fact, Jim Lovell’s crew themselves had been the backups to Neil Armstrong’s crew for the historic Apollo 11 mission. The backups for Apollo 13 would be John Young, played by Ben Marley in the movie, Jack Swigert, or Kevin Bacon in the film, and Charles Duke who wasn’t even portrayed in the film.

While the movie’s reasoning wasn’t correct, the result was: Jim Lovell’s crew would be heading to space on Apollo 13. And it would be his last. This part of the movie is true, when Tom Hanks’ portrayal of Jim Lovell announces it will be his final trip to space.

In the movie, there’s yet another change in plans when Deke meets up with Jim to deliver some bad news. Charlie Duke has the measles. Duke isn’t played in the movie, but because of this sickness, the rest of the crew is at risk. They’ve all been exposed, and NASA can’t risk the astronauts coming down with the measles in space. Jim and Fred have had the measles before, so they’re not at risk to get it again. But Ken Mattingly, Gary Sinise’s character, hasn’t. So he’s scrubbed from the mission, replaced with Kevin Bacon’s character—Jack Swigert as Command Module Pilot.

This actually happened. Just seventy-two hours before Apollo 13 was slated to launch, Ken Mattingly was removed from the mission because of an exposure to German measles. And in the movie, after Gary Sinise receives the news, he says, “Look–I don’t have the measles. And I’m not going to get the measles.”

While we don’t really know the specifics of the conversation, the truth is Ken never got the measles. It was a risk that never came to pass. But as history now tells us, the three astronauts who actually launched with Apollo 13 were Jim Lovell, the mission’s Commander, Jack Swigert as Command Module Pilot, and Fred Haise as Lunar Module Pilot.

Although there were significant personnel changes before the launch, just like in the movie, the launch of the Apollo 13 went off without a hitch. On April 11th, 1970 at 3:13 PM local time, a Saturn V rocket launched Jim, Jack and Fred on Apollo 13 from Kennedy Space Center in Florida.

Here we’re hit with one of the least accurate things in the movie when it depicts Ken sitting on his car watching the launch from miles away. In truth, Ken Mattingly was at the Mission Control Center during the launch. So if that’s one of the least accurate things, you can get a sense for how well Hollywood did retelling this tale. In fact, most of the issues were with details omitted—not changed.

While the launch itself may not have had a hitch, in the movie, there’s a problem almost right away once the rocket is in the air. Engine #5 in the center of the rocket stopped working. This actually happened. Five minutes after launch, engine #5 on the Saturn rocket cutoff. The official transcript of communication between the astronauts and CAPCOM in Houston reads:

Swigert: “Inboard.”

CAPCOM: “We confirm inboard out.”

Lovell: “That shouldn’t have happened.”

Swigert: “No, that’s 000:07:42. That’s two minutes early.”

What Jack Swigert is referring to there is that engine #5 should have turned off at seven minutes and forty-two seconds into the flight. Instead, Jack was looking at the mission clock which read five minutes and thirty seconds. The engine shut off two minutes before it was supposed to. According to NASA’s official records of the flight, it was 132.36 seconds earlier than it should have cut off.

While not enough to abort the mission, anytime something doesn’t go according to plan it’s cause for concern. Still, the mission went ahead. In the movie, the mission clock shows twelve minutes when the crew enters orbit. This timing is correct. Twelve minutes after launch, at 19:25:32 GMT, or 3:25 PM Florida time, the three astronauts entered Earth’s orbit.

Shortly after they reach orbit, one of the first, big challenges happens. It’s time for Jack to work his magic. Jack Swigert, or Kevin Bacon’s character, was the one who, in the movie, managed to kill the three astronauts numerous times back on Earth while they were training for the mission. How would he hold up when they’re in space? 

Well, in the movie everything went according to plan. Kevin Bacon’s version of Swigert managed to dock the Command Module with the Lunar Excursion Module, or LEM.

This is true. Despite having troubles during training, and despite being told he was going to space just three days before the mission, Jack did a stellar job of piloting the Command Module into place to successfully dock with the LEM. And while the purpose of the mission was to reach the moon, hence the name Lunar Excursion Module, it was this successful docking that would soon save all of their lives.

As a quick side note, it’s worth pointing out that sometimes the LEM is shortened to just the Lunar Module, or LM. Another confusing part is that the Command Module and Lunar Module each had nicknames. The Command Module was the Odyssey while the Lunar Module was Aquarius.

Actually the most inaccurate part of this scene in the movie is most likely the end of the shot when everyone cheers the successful docking before changing shifts. In truth, Flight Director Gene Kranz, who’s played by Ed Harris in the film, ran a pretty strict Mission Control. Suffice it to say, there probably wasn’t a lot of cheering and high fives in Kranz’s control room. He was all business and the mission was far from over—celebrations would have to wait.

What the movie did get right next, though, is that the crew from Apollo 13 performed TV broadcasts. While they didn’t make it to national TV—the networks simply didn’t feel the Apollo missions would get good ratings—they did happen. In fact, you can even find some of the original transmissions on YouTube.

In the movie, it seems like it’s right after the crew ends their TV transmission that everything starts to go wrong. In truth, it was a little more time than that. And there were actually multiple TV transmissions. Their second TV transmission ended at 031:02 (thirty-one hours and two minutes) on the mission clock. At 046:40, the astronauts performed a routine procedure when they turned on the fans in oxygen tank #2.

The gauge on the tank indicated it was “off-scale high”. While strange, it was similar to the rocket shutting off early at launch—it was something they wanted to keep an eye on, but things didn’t get dangerous right away. In fact, it was only in retrospect that NASA’s engineers really nailed down that this was the first sign of a problem.

Almost ten hours later, at 055:14 on the mission clock, the crew had another TV transmission, this one lasting for forty-nine minutes. And it happened a lot like it did in the movie. Everyone was blissfully unaware of what was about to happen as the crew showed those watching the broadcast back on Earth how they lived and worked in the weightlessness of space.

In the movie right after the broadcast, CAPCOM asks Jack to perform a few “housekeeping items”. One of those being a stir of the oxygen tanks. When Kevin Bacon’s version of Jack Swigert reaches to do that is when it sets off a chain reaction of disaster.

While they did stir the tanks, the movie doesn’t really give much of an explanation as to why they did, other than that Mission Command asked them to. In truth, there was a little more to it.

Half an hour after this third TV transmission, an alarm went off. The crew on Apollo 13 shut the alarm off after only four seconds. The alarm was triggered by low hydrogen pressure in oxygen tank #1. The same tank that showed “off-scale high” on the gauge earlier.

When you hear the term “alarm”, your first thought is that something went wrong, but that’s not necessarily the case. Think of these alarms sort of like a “Check Engine” light in your car. Sure, it could mean a major problem. Or it could just be a caution; not really a big deal.

With this particular alarm, there was two things that it could’ve meant. Either it could actually be a problem, or it could’ve just been that the sensor was indicating the hydrogen in the tank needed to be resettled. This process was essentially to keep the gas from settling into layers, as it can do when it’s chilled to incredibly cold temperatures in space. To keep it from settling, it was a normal procedure to periodically heat and fan the hydrogen gas inside the tank.

Sort of like when you see the instructions on a bottle of juice to shake before opening—you just need to stir any sediment that may have settled at the bottom of the bottle.

This is about two days into the mission and while there’s been a few hiccups along the way, up until this point Apollo 13 was actually the smoothest of the space programs so far. In fact, at about this point in the mission, one of the capsule commanders, or CAPCOM back at Mission Control in Houston, said, “The spacecraft is in real good shape as far as we are concerned. We’re bored to tears down here.”

This was a man by the name of Joe Kerwin. Although Kerwin didn’t have an official role in the movie, Brett Cullen played a character simply titled “CAPCOM 1” which was probably based on him.

Needless to say, everything was about to change.

After the alarm went off, Mission Control in Houston wanted to try spinning the fans to see if it fixed the cause of the alarm—sort of like rebooting a computer. All of this is fairly accurately depicted in the movie. You can tell how low-key the tone of voice was from Mission Control in the official transcript from NASA:

CAPCOM: “13, we’ve got one more item for you, when you get a chance. We’d like you to stir up your cryo tanks. In addition, I have shaft and trunnion…”

Swigert: “Okay.”

CAPCOM: “…for looking at the Comet Bennett, if you need it.”

Swigert: “Okay. Stand by.”

At 055:53, the fans in oxygen tank #1 turned on. Then the fans in tank #2 kicked on. Just four seconds after the tanks were switched on, there was an electrical short in tank #2. Pressure in the oxygen tanks started to decrease…then increase. They were fluctuating as a voltage spike was indicated in the fuel cell.

While we’ll never know exactly what it was like on board Apollo 13 when this happened, the movie does a pretty good job of showing the ensuing chaos.

Then, about one minute later, at 055:54, the ship suddenly started to roll, pitch and yaw on all axes. What happened was that tank #2 had lost pressure and a panel had separated, much like what you see happen in the movie. There was also a loud bang—something you never want to hear in outer space.

There was also a master caution alarm that was triggered by the main bus B showing as being under voltage. Of course, they didn’t really need the alarm as the ship was losing control. Just like in the movie, due to the short there was an instant fluctuation of pressure that no doubt would’ve caused quite a ripple through the spaceship.

This time the alarm was turned off after six seconds.

As an effect of the fluctuations, the power cell’s voltage started to decrease much more than normal. They were losing power. Again, something you don’t want to happen in outer space.

Things were about to go from bad to worse.

In the movie, Kevin Bacon’s Jack Swigert says, “Hey, we’ve got a problem here.”

Tom Hank’s version of Jim Lovell says, “What did you do?”

Jack replies, “Nothing—I stirred the tanks!”

CAPCOM’s reply, “This is Houston. Uh, say again, please?”

Then the camera focuses in on Tom Hanks as he says what’s gone on to be the most famous quote from the film: “Houston, we have a problem.”

While the essence of this exchange is very accurate, it’s not entirely accurate. And since that’s the most famous line of the movie, we should probably clarify what actually happened. We know exactly what happened from the official NASA transcripts, from which we can learn that it was at 055:55 when Jack announced on the radio: “Okay, Houston, we’ve had a problem here.”

CAPCOM: “This is Houston. Say again, please.”

Lovell: “Houston, we’ve had a problem. We’ve had a main B bus undervolt.”

CAPCOM: “Roger. Main B bus undervolt.”

After a short pause, Fred Haise spoke up, “Okay. Right now, Houston, the voltage is—is looking good. And we had a pretty large bang associated with the caution and warning there. And as I recall, main B was the one that had an amp spike on it once before.”

CAPCOM: “Roger, Fred.”

Haise: “In the interim here, we’re going to go ahead and button up the tunnel again. That jolt must have rocked the sensor on. See now—O2 oxygen quantity 2. It was oscillating down around 20 to 60 percent. Now it’s full-scale high.”

So as you can tell from that exchange, it was actually Jack Swigert who said the famous line first. And it wasn’t exactly as Tom Hanks said it.

In the movie, Jim Lovell is listing off all of the issues that are happening as alarms are blaring. Back in Houston, they list issues with oxygen tanks #1 and #2 as well as fuel cells #1 and #3. A lot of this is very accurate.

One of the first things Jim Lovell says in the movie is, “Let’s get that hatch buttoned, the LEM might’ve been hit by a meteor.”

While they didn’t know exactly what was going on, this is pretty accurate. That’s what Fred Haise was talking about when he told Houston about the large bang and that they were going to button up the tunnel.

So in truth the first thing the astronauts tried to do was to close the hatch between the Command Module and the Lunar Module. One of their two oxygen tanks was showing it was completely empty, so they figured there had to be a leak somewhere. And like a crew on a submarine they wanted to isolate the leak. Jack tried to lock the hatch, but when it wouldn’t work he gave way to Lovell, who also couldn’t keep the hatch shut.

That’s when they realized it wasn’t a leak in their cabin; they had strapped the hatch to their seats to keep it from closing. But in what was no doubt a frantic state of high stress, they had forgotten this simple fact. So there was a leak, but it wasn’t from their cabin.

Within two minutes, one of their main power cells had dropped from over 30 volts to below 26 volts and continued to fall. Then fuel cell #3 failed. Then the AC bus #2 was reset, causing another master caution alarm. Then main bus A started to lose power and showed under voltage—the same thing that happened with main bus B earlier.

There were warning lights indicating two of the three fuel cells were lost.

Whether or not you know what all of these different components are and what they do is beside the point. Oxygen pressure started to fall, and they essentially lost power. You don’t have to know a lot about Apollo spacecraft to know this many consecutive failures in outer space is not good. The ball started to roll, and more and more things failed.

The mission clock ticked its way to a new hour, 056:00.

Another master caution alarm went off, triggering a warning that the flow of hydrogen into fuel cell #2 was too high. This is when, in the movie, Tom Hanks’ character happens to notice something. The chaos in the movie comes to a dramatic pause as he looks out the window. There’s a gas. Something leaking.

This, too, is accurate. Again, not good.

The official transcript from NASA gives us great insight into not only what actually happened, but while I’m sure their hearts were racing, you also get a sense of how calm the astronauts were considering their ship was breaking down around them.

Lovell: “It looks to me, looking out the hatch, that we are venting something. We are venting something out into the—into space.”

Again, not good. Although the astronauts didn’t know it at the time, we now know what was leaking was oxygen. And since one of their two tanks had blown up—that was the bang they heard before—that meant their last oxygen tank was now leaking into space. Of course, they didn’t know all of those details at the time. All the astronauts knew was something that’s pretty much common sense: anything leaking into space is not good.

We can only imagine what horrors were exploding through the minds of everyone in Houston, not to mention the two astronauts sitting right next to Lovell as he said it.

In the movie, Bill Paxton’s version of Fred Haise makes a realization as he says, “We’re not going to have power much longer. The ship’s bleeding to death.”

This is when, again in the movie, Sy Liebergot—who’s played by Ron Howard’s younger brother, Clint Howard, in the movie, suggests they shut off the damaged fuel cells to try to isolate the issue. Gene Kranz, Ed Harris in the movie, makes the point that if they do this there’s no way they’re landing on the moon.

While we don’t know if it went down exactly like that, the end result of this conversation in the movie between Clint Howard and Ed Harris is very true. It was a sobering reality. Forced to make quick decisions, Kranz made the best one he could. Shut down the fuel cells.

The mission would no longer be about landing on the moon. While the basic premise of this is true, it didn’t happen in exactly that order.

At 056:09, fuel cell #1 went offline. Houston told the Apollo 13 crew to leave cells #2 and #3 alone. They didn’t get shut down until about half an hour later when fuel cell #3 was shut down at 056:34 and fuel cell #2 finally was shut down at 058:00.

Still, as the mission clock ticked its way to 056:10, the crew was faced with a Command Module without any power, and losing oxygen. At this point, oxygen tank #1 was at about 300 pounds per square inch. Once the pressure reached below 200, they’d lose all oxygen in the cabin and the final fuel cell would die.

They were over 200,000 miles from Earth and left without light, electricity or water. To borrow the phrase, the Command Module was dead in the water—dead in space, to be more accurate.

And the astronauts would be, too, if they didn’t do something fast. At 056:33 in the mission, the astronauts initiated an emergency power-down of the Command Module.

In the movie, Lovell asks Haise how long it takes to power up the LEM.

“Three hours by the checklist,” comes the reply.

“We don’t have that much time.”

This didn’t happen exactly as it did in the movie, but the essence of the story is pretty accurate.

The three astronauts knew the LEM would be their only hope of survival. After all, the Command Module was going to be dead soon—and without oxygen they’d follow soon after.

About an hour and a half after the initial bang that caused this descent into chaos, the radio buzzed to life.

CAPCOM: “It is slowly going to zero, and we are starting to think about the LEM as a lifeboat.”

They were referring to the dipping oxygen levels.

Jack replied, “That’s what we have been thinking about, too.”

Although the plan for the mission was to use the Lunar Module for the moon, hence the name, they didn’t have much choice.

In the movie, it appears that Jack stays behind in the Command Module for a while as Lovell and Haise move to the LEM. The movie tells us Jack stayed behind to transfer the guidance system over from the CM to the LEM. This is true as well. Since the LEM wasn’t planned to guide the astronauts back to earth, they had to transfer as much of this information over as they could before the module died. As the Command Module Pilot, Jack was tasked with this before moving over.

At 057:41, CAPCOM asked the astronauts to start moving to the LEM: “13, Houston. We’d like you to start making your way over to the LEM now.”

Two minutes later, Jack replied, “Fred and Jim are in the LEM.”

Although the LEM was a great lifeboat, it was far from a perfect one. It was built and designed to go to the moon, not to pilot them back to Earth. At this point the movie does something very few Hollywood movies do—it makes math seem intense, as the scientists and engineers back at Mission Control check the math of a gimbal angle conversion between the Command Module and the LEM.

This actually happened!

At 058:04, Lovell asked Houston to double-check his arithmetic, which they did and confirmed it was good three minutes later. Of course, this happens a lot faster and with a lot more thrilling music in the background to build the intensity. So even though Hollywood has some creative license here, it’s worth mentioning these little details because they did a great job making sure even little details like this were included in the film.

At 058:10 on the mission clock, the Command Module computer was powered down. Exactly half an hour later, at 058:40, the LEM systems were powered up. At the same time, the rest of the Command Module was powered down.

Lovell confirmed this to Mission Control, “Okay. Odyssey is completely powered down according to the procedure that you read to Jack.”

CAPCOM: “Roger; we copy. That’s where we want to be, Jim.”

Cutting back to the movie, you can sense the frustration growing among the astronauts as you hear Tom Hanks’ voice at Mission Control as his version of Jim Lovell starts swearing. Houston says they’re on VOX, or voice operated switching. Essentially, everyone can hear Lovell swearing.

The movie makes this seem important because it’s the first swearing any of the astronauts have done. Again, Hollywood took some creative license to change something that happened to keep the plot of the movie going.

The biggest difference is that the first swearing happened about an hour before this when Fred said of Mission Control, “I wish I knew what the hell they were thinking right now…”

But this was the first time the astronauts ever said the word “damn”. The first of seven, according to NASA’s official transcripts. Even for this exchange shown in the movie, there were a couple key differences. First, the movie makes it seem like this was right after the crew got into the LEM. In truth, it was about an hour and a half afterward, at 059:10 on the mission clock. Secondly, the movie makes it seem like Lovell is piloting the LEM and trying to keep it stable. In truth, it was Jack who swore as the three were trying to get the mission timer working in the LEM.

CAPCOM: “Aquarius, Houston. I think we’ve got a better way of getting your mission time up.”

Lovell: “Go ahead with it.”

CAPCOM: “Okay. We can do VERB 55, ENTER, then put RI, minus 00088. In R2, minus 00059; R3 minus 03274.”

Haise: “Watch the crapping attitude.”

Lovell: “We’re okay.”

Swigert: “God damn. I wish you’d get to something I know.”

Lovell: “Well, as soon as we get over here, we’ll stop it with the TTCA.”

Swigert: “Okay.”

CAPCOM: “And, Aquarius; Houston. We’ve got you both on VOX.”

Haise: “Like to go what?”

Lovell: “You want us on VOX, Jack?”

CAPCOM: “We have you on VOX. We’re reading you loud and clear and the clock took good.”

So as you can tell, the crew was starting to get a bit antsy. Oh, and TTCA means the Thrust/Translation Controller Assembly. The importance of this exchange isn’t so much what they were doing, but it shows how frustrated the astronauts are getting at this point. Even still, they’re working through the problems.

In the movie, Gene Kranz pulls a bunch of scientists and engineers into a room to figure out what trajectory to use to get the astronauts home. Any plans they had before are scrapped. With the ship headed toward the moon, do they turn around right now? Ultimately, they decide to swing around the moon and perform a long burn with the LEM’s engines to try to make it home.

As a quick side note here, at this point in the movie—and throughout—any time you see Apollo 13 hurdling toward the moon, that’s not really accurate. In reality it would be targeted ahead of the moon. That way, as the moon itself moves, Apollo 13 would intercept it.

Like most movies do, the timeline gets sped up quite a bit. At 077:08 on the mission clock, almost twenty hours after Jack swore, the LEM entered the moon’s orbit. Their final words were garbled as the radio lost signal with earth. It was Jim saying, “You…up our edibles? … water? …”

There’s a moment in the movie where everyone holds their breath as they swing around the moon. While we don’t know how many actually held their breath, it’s fair to say this probably happened. For twenty-five minutes, there was no word from the astronauts. We can only guess at what was running through everyone’s minds.

In the movie, it’s Houston who breaks the silence. But in truth, it was at 077:33, when the radio at Mission Control crackled to life again as Jim’s familiar voice came through, “Good morning, Houston. How do you read?”

Now, the next problem. In the movie, they realize they only have about 12 hours of power left in the LEM. That’s not enough to get home. They’ll have to turn everything off to conserve power. But first, they need to do a long burn to gain speed as they shoot back toward Earth. It’s during this scene that Ed Harris’s version of Gene Kranz informs his team that they need to start working on the next problem, how to turn on the Command Module for re-entry. It’s been off, freezing in space. Now, they need to find out how to squeeze every amp out of both the Command Module and the Lunar Module.

The basics of this happened, but of course this was all sped up quite a bit in the movie.

At 079:27, Apollo 13 initiated a burn of their engine to propel them toward Earth. Then, exactly five minutes later, at 079:32, they shut down the engine. It wasn’t for another two and a half hours, at 082:10 on the mission clock, that the LEM systems were powered down.

With all of the electrical systems shut down, there was no heat. Temperatures inside the LEM dropped to about 38 degrees Fahrenheit, and condensation started to form on the walls. There was a very real concern that they may not be able to turn the power back on. After all, things hadn’t exactly gone according to plan so far.

In the movie, this is when Ken Mattingly, Gary Sinise, comes back into the picture. He’s woken up and told of the situation as he heads back to Mission Control to run through simulations.

In truth, Ken Mattingly played a huge role in helping the astronauts make it back safely. He ran through simulations so that Mission Control could at least run some tests before trying things with the crew in space.

Another point they make in the movie is sleep. There’s an engineer talking to Deke Slayton, played by Chris Ellis in the film, saying the astronauts haven’t slept since the explosion. Deke replies with, “I can’t order them to go to sleep.”

Then the movie goes on to describe an issue with CO2 on the rise. As you can probably guess by now, the core elements of this are true.

At 082:54 on the mission clock, CAPCOM made note of the CO2 issue.

CAPCOM: “Fred, your CO2 is building up. It’s at 11.3 on our gauge, and we’ve got a medical buildup to 15 millimeters, at which time we’ll switch over to secondary. Looks like we’ve got plenty of lithium hydroxide, about 192 hours including the CSM cartridges. And as you know, we’ve got a way to use those. And as soon as we get them written in some good words, why, we’ll pass that along. You might be able to make one.”

Haise: “Okay. Yes, we’ll sure give her a try. And I’m showing onboard about 12-1/2 millimeters of mercury.”

What Fred is referring to with the mercury is the gauge for the CO2 levels. In the movie the gauge is indicated as a little arrow, but in reality they used mercury levels at specific millimeter heights to determine the levels of CO2. Think of it just like a thermostat telling the temperature. As the heat rises, so does the mercury. Similar situation, so by saying they’re at 10.6 they’re indicating the mercury is at 10.6 millimeters.

At this point, they’re going on over eighty hours since the launch. And while the crew on board Apollo 13 didn’t get much sleep, they did try…well, as much as you can expect to try in space when you’re in a struggle for your life. This is indicated in the NASA transcripts, at 082:24 after Mission Control has walked Jim and Jack through a series of instructions to power down the LEM. After that is when they indicate the CO2 issues.

CAPCOM: “Okay. It’s time for you guys to get to bed and get Fred up.”

Lovell: [Laughs] “I still have one question, Jack. I still think that—I still say that the lighting on our panel 16, the flood lights and the track should be open. We’re not using them.”

CAPCOM: “No problem, Jim. Go ahead and open them, track and flood, that’s alright.”

Swigert: “Okay, track and flood are open.”

Lovell: “Now, why don’t you go through that, Jack, and make sure those—”

Swigert: “Yes.”

After a brief pause, Jack spoke again.

Swigert: “Okay, I’ll take this.”

Lovell: “Okay, Jack, my only other concern now is the COg rise in the spacecraft. I guess you’re keeping a handle on that?”

CAPCOM: “That’s affirmed, Jim. We have you up to 10.6 now, and we’re willing to go a little higher on that. We have another cartridge and a procedure for making the command module cartridge, up. We’ll pass that on later.”

Lovell: “Oh yes, I’m not worried about that. I just wanted to make sure that…we just don’t want to go to sleep here and forget about the rise in CO2.”

CAPCOM: “Roger. We’re watching it for you—”

Lovell: “Yes, they’re getting it—”

CAPCOM: “We have it here. It’s now 10.7 and we have a medical go to 15 millimeters.”

Swigert: “That’s a new one.”

Lovell: “There’s a new first for you.”

CAPCOM: “Okay, Jim, estimate we’ve got one more hour on the primary cartridge, and six or seven hours on the secondary.”

Lovell: “Okay. Fine. Say, it’s a spare, primary cartridge back there, too, isn’t it? That’s good for another, how long?”

Swigert: “Yes. Yes. That’s yours, though, isn’t it?”

CAPCOM: “And you’re right, Jim. We’ve got another primary cartridge back there behind the ascent engine cover.”

Lovell: “Right, yes. We know. Thank you.”

So that was a rather long exchange, but you can get a sense for how the astronauts, although I’m sure they were exhausted, had plenty of concerns—and sleep didn’t really seem to be one of them. The extreme cold made it incredibly tough for the astronauts to sleep. The fact that everything around them seemed to be going wrong made it tough to sleep. But they knew the importance of getting rest, so they did try.

In the movie, this is another key moment where they realize once the CO2 filters they have are used up they need to figure out a way to get the Command Module’s square filters to fit into the LEM’s round slots.

At this point, you can’t help but wonder if this moment was one of the real inspirations behind the recent and hugely popular movie, The Martian. At the end of that movie, there’s a quote that says:

“At some point, everything’s gonna go south on you… everything’s going to go south and you’re going to say, this is it. This is how I end. Now you can either accept that, or you can get to work. That’s all it is. You just begin. You do the math. You solve one problem… and you solve the next one… and then the next. And If you solve enough problems, you get to come home.”

Although we don’t know if this specific quote from The Martian was inspired by Apollo 13, Andy Weir, the author of The Martian did highlight the movie Apollo 13 as one of his inspirations for the book. In an interview with the website Inverse, Weir said:

“…I was more inspired by Apollo 13, especially that one scene where they have to make the lunar module CO2 system work with the command module’s filters. It was just that scene where they’re kinda of like, ‘Put a bag in, put a hose here, stuff it back in this hole,’ I mean I just loved it. I loved that kind of extremely resourceful problem solving stuff, and I wanted to make a whole book of it.”

There certainly was an issue with CO2 on Apollo 13. About three hours after they had a reading of 10.7 for CO2, the CO2 was up to the max threshold of 15. Any higher than that, and NASA’s medical staff was concerned they’d start to pass out. So at 085:22, CAPCOM had Fred swap out the primary cartridge with the secondary. This dropped the CO2 to 4.5.

But that was a temporary solution. It wouldn’t last until they got back to Earth.

Back at Mission Control, there was a team trying to build filters for the lithium hydroxide canister, something that would help them remove CO2. While this functioned fine on the LEM, the issue was that the LEM was designed to support two men for two days. This was by design, since Swigert, as the Command Module Pilot, was never intended to leave the Command Module and join the team in the LEM for landing on the moon. All of a sudden, instead of having to support two men for two days in the LEM, the canister had to support three men for four days.

Because of this, the filters for the canister wouldn’t last as long as originally intended. The Command Module had plenty of them, but just like in the movie, these filters were square whereas the ones on the LEM were round. Through plenty of hard work, genius engineering, and plenty of duct tape, the NASA engineers were able to come up with a solution using only what they had on Apollo 13. It was pretty much made from plastic bags, cardboard, suit hoses and duct tape.

Just like in the movie, at 090:07 on the mission clock, CAPCOM started giving the astronauts the instructions for putting a square peg in a round hole. The movie makes it seem like they were able to put it together pretty quickly, but it wasn’t a quick process. It took about an hour of detailed step-by-step instructions before, at 091:10 on the mission clock, Jack confirmed to Joe Kerwin, CAPCOM, that the canister was in place.

Swigert: “Okay. Our do-it-yourself lithium hydroxide canister change is complete. Joe, the only thing different is that our arch on this piece of cardboard is not big enough to position the red hose with the inlet down, and the inlet—the inlet to—to the red hose is lying on its side, but I think it’ll still work.”

And it did work. They actually made a couple canisters that the astronauts were able to use to keep the CO2 levels down for the rest of their trip.

Something the movie didn’t touch on was a short-circuit in the LEM’s electrical system that happened at 097:13. Well, that’s what we assume it was. The crew heard a thump, but they couldn’t tell what it was. Since nothing appeared to go wrong, and they had enough to worry about, they didn’t take the time to try to investigate. Still, it had to have been a heart-stopping moment…something that likely reminded them of the bang they heard days before that started the whole thing.

The next major hurdle in the movie is the angle of re-entry into Earth’s atmosphere. And again, Hollywood hit the core elements.

This was definitely a concern. At 102:51, Jim reached out to Mission Control.

Lovell: “Houston, Aquarius.”

CAPCOM: “Roger. Go ahead.”

Lovell: “I just want to talk over a little philosophy here. Fred told me that at one time you came up and told him that we were a little steep on the entry angle, and now our burn is going to make us—give us a steeper angle. I just want to make sure that we’re all talking about the same thing, that, in essence, at this particular situation, we’re shallow, are not steep, and we are going to in- crease the angle.”

CAPCOM: ” Jim, the situation is that, at the moment, we’re a little bit shallow, and retrograde midcourse is going to put us more in the center of the corridor. Over.”

Lovell: “Okay; fine. I just, wanted to make sure. Fred had written down, some time ago, that—that our angle now was about 71 and we were going to do a midcourse of 7 feet per second because it appears that we’re going to shallow it out. I think we’re all talking the same language now.”

CAPCOM: “Roger. And, I guess it follows, but your perigee is a little bit high right now, too; so that will be bringing it back – back down, that is.”

Lovell: “Yes. Yes, that’s the important thing.”

CAPCOM: “One other question, Jim. Our readings down here say your LEM cabin’s about as cold as the command module cabin. Is that right?”

Lovell: “Well, we really don’t know. There’s usually two people in the LEM cabin, and it’s a lot – It seems to be a lot more compact, and so we don’t notice the coldness down here as we do in the command module.”

CAPCOM: “Okay.”

Again, the movie speeds up the timeline some. At 137:39, the three astronauts initiated a burn to propel them toward Earth and change their trajectory. The burn took place for about one minute. After this, their next big challenge was to power up the Command Module. They had shut it off days before when they went into the LEM, but there was no way the LEM would survive re-entry into Earth’s atmosphere. So they had to use the Command Module.

Here’s where the movie gets things out of order a bit. According to the movie, after the Command Module is powered back up, the Service Module is jettisoned—let go, giving the Apollo 13 crew their first looks at the damaged panel that exploded earlier.

In truth, the Service Module was separated at 138:02, and the Command Module was powered up two hours later at 140:10.

But this did offer the astronauts a look at the damage, and we can get a feeling for the extent of it from their communications back with Mission Control.

Lovell: “SM separated.”

CAPCOM: “Copy that.”

Lovell: “Do you see it, Jack?” 

CAPCOM: “Okay, Aquarius; Houston. I recommend you terminate average G. Over.”

Lovell: “Okay, I’ve got her, Houston.”

CAPCOM: “Beautiful, beautiful. And for your information, Jim, you’ll be coming up on an RCS caution light for helium. No sweat. Over.”

Lovell: “There’s one whole side of that spacecraft missing.”

CAPCOM: “Is that right?”

Lovell: “Right by the—look out there, will you? Right by the high gain antenna, the whole panel is blown out, almost from the base to the engine.”

CAPCOM: “Copy that.”

Haise: “Yes, it looks like it got to the SPS bell, too, Houston.”

CAPCOM: “Think it zinged the SPS engine bell, huh?”

Haise: “That’s the way it looks; unless that’s just a dark brown streak. It’s really a mess.” 

CAPCOM: “Okay, Jim. We’d like you to get some pictures, but we want you to conserve RCS. Don’t make unnecessary maneuvers.”

Online, you can find the actual photos of the Service Module that the Apollo 13 crew took. Two hours later, at 140:09, CAPCOM gave them a “go” to start powering up the Command Module.

Fred and Jack went into the Command Module to start powering it up while Jim stayed in the LEM to communicate with Mission Control. In the movie, Gary Sinise’s character, Ken Mattingly, arrives at Mission Control to walk them through a unique start-up procedure he’s devised in the simulator.

It didn’t really happen that way, although Ken Mattingly certainly did help. What he did was to essentially to verify that the procedures they already had in place for starting up the Command Module would work in their conditions. Ken Mattingly himself explained it in an interview about the differences between the movie and reality on NASA’s website:

“We said, ‘Let’s get somebody cold to go run the procedures.’ So I think it was [Thomas P.] Stafford, [Joe H.] Engle — I don’t know who was the third person, might have been [Stuart A.] Roosa. But anyhow, they went to the simulator there at JSC [Johnson Space Center], and we handed them these big written procedures and said, ‘Here. We’re going to call these out to you, and we want you to go through, just like Jack will. We’ll read it up to you.’ See if there are nomenclatures that we have made confusing or whatever. Just wring it out. See if there’s anything in the process that doesn’t work.”

And it did work. The Command Module powered up. The first communication from Odyssey after powering back up came from Jack.

Swigert: “Joe, how do you read?”

CAPCOM: “Okay. Read you, babe.”

After the Odyssey was up and running, the three astronauts moved into there, buttoned up the hatch and prepared to dump the LEM. This happened at 141:30. The movie got this part right when CAPCOM says, “Farewell, Aquarius, and we thank you.”

For re-entry, the movie makes a point of laying out all the problems that could occur—the angle could be wrong, the guidance system could be malfunctioning, the thrusters may be frozen, the heat shield could’ve cracked, their parachutes may be blocks of ice…so how will they know if it worked? According to the movie, the communication blackout lasts for three minutes. If they’re not back in four…we’ll know.

That’s pretty much true. There’s a thousand things that could’ve caused the Command Module to burn up on re-entry into Earth’s atmosphere. Even staring at potential death just minutes away, the astronauts were up for cracking jokes.

At 142:30 on the mission clock.

CAPCOM: “Okay. At 10 minutes to 400 K, you’re looking good; we’re real happy with the trajectory, and a minute ago, we just lost contact with your friend Aquarius.”

Swigert: “Okay. Where did she go?”

CAPCOM: “Oh, I don’t know. She’s up there somewhere.”

Swigert: “She sure was a good ship.”

CAPCOM: “Hey, just as I said that, we got another burst of LM data, so I guess it’s still ticking.”

CAPCOM: “Odyssey, Houston. Your DSKY is doing all the right things. The G&N is GO. Over.”

Swigert: “Okay. Thank you.”

Swigert: “You have a good bedside manner, Joe.”

CAPCOM: “Say again, Jack.”

Swigert: “You have a good bedside manner.”

CAPCOM: [Laughter] “That’s the nicest thing anybody’s ever said! How about that?”

Swigert: “Sure wish I could go to the FIDO party tonight.”

CAPCOM: [Laughter] “Yes, it’s going to be a wild one.”

CAPCOM: “Somebody said, ‘We’ll – We’ll cover for you guys; and, if Jack’s got any phone numbers he wants us to call, why, pass them down.'”

A few moments passed.

CAPCOM: “Odyssey, Houston. Over.”

Swigert: “Go ahead.”

CAPCOM: “Okay; We just had one last time around the room and everybody says you’re looking great.”

Swigert: “Thank you.”

Again, silence for a few moments.

CAPCOM: “Odyssey, Houston. Over.”

Swigert: “Go ahead.”

CAPCOM: “Okay. Loss of signal in about a minute or minute and a half; in entry attitude, we’d like OMNI Charlie, and welcome home. Over.”

Swigert: “Thank you.”

That was at 142:38.

One minute passed.

Two.

We don’t know what it was like in Mission Control, but it’s probably safe to assume there wasn’t a lot going on as everyone stared at the clock.

Three.

They should hear back from them by now.

Four.

In the movie, there’s static as Ken Mattingly tries to reach Apollo 13 on radio. Much of this is built up for dramatic effect in the movie.

Five minutes passed.

At six minutes since re-entry, or 142:46 on the mission clock, CAPCOM reached out.

CAPCOM: “Odyssey, Houston standing by. Over.”

Five second later, Swigert replied, “Okay, Joe.”

CAPCOM: “Okay. We read you, Jack. We’re looking at the weather on TV and it looks just as advertised; real good.”

In the movie, everyone erupts into cheers—even in Mission Control. In truth, that didn’t happen. While everyone was certainly happy, but Gene Kranz was known for running a very strict operation and reports afterward say that was all hyped up for dramatic effect in the movie.

In truth, CAPCOM said: “Odyssey, Houston. We show you on the mains. It really looks great.”

Then, after a pause: “Got you on television, babe.”

The Apollo 13 Command Module splashed down in the Pacific Ocean near Samoa on July 11, 1970. It was rescue crews on the USS Iwo Jima that picked up the three astronauts.

As a side note, one fun little fact about the movie Apollo 13 is that the real Jim and Marilyn Lovell made their way into the movie. Marilyn was in the beginning of the movie, as an uncredited extra at the launch. Then, here at the end, the real Jim Lovell himself plays the captain of the USS Iwo Jima.

The movie ends as Tom Hanks explains that the mission was determined a “successful failure” by NASA, and explains what happened afterward. This depiction is also accurate. To quote from NASA:

“The No. 2 oxygen tank, serial number 10024X-TA0009, had been previously installed in the service module of Apollo 10, but was removed for modification and damaged in the process. The tank was fixed, tested at the factory, installed in the Apollo 13 service module and tested again during the Countdown Demonstration Test at NASA’s Kennedy Space Center beginning March 16, 1970. The tanks normally are emptied to about half full. No. 1 behaved all right, but No. 2 dropped to only 92 percent of capacity. Gaseous oxygen at 80 pounds per square inch was applied through the vent line to expel the liquid oxygen, but to no avail. An interim discrepancy report was written, and on March 27, two weeks before launch, detanking operations resumed. No. 1 again emptied normally, but No. 2 did not. After a conference with contractor and NASA personnel, the test director decided to ‘boil off’ the remaining oxygen in No. 2 by using the electrical heater within the tank. The technique worked, but it took eight hours of 65-volt DC power from the ground support equipment to dissipate the oxygen. Due to an oversight in replacing an underrated component during a design modification, this turned out to severely damage the internal heating elements of the tank.

Apollo 13 was to be the third lunar landing attempt, but the mission was aborted after rupture of service module oxygen tank. Still, it was classified as a ‘successful failure’ because of the experience gained in rescuing the crew. The mission’s spent upper stage successfully impacted the moon.”

As of this writing, Fred Haise is still alive at the age of 82. He never made it back into space after Apollo 13.

Jim Lovell is also alive; he’s 88 years old. The Apollo 13 mission made Jim the first person to ever have flown in space four times. But it would be his last.

Jack Swigert also never went back to space. He was elected to the U.S. Congress in 1982, but passed away from cancer eight days before he was to take office.

Ken Mattingly, on the other hand, did end up getting his time in space. He joined the Apollo 16 crew alongside Charles Duke, the man who came down with the measles and kept Ken from joining the Apollo 13 crew. Unlike the Apollo 13 mission, Ken’s Apollo 16 mission achieved all of its major objectives thanks to the most rigorous preflight planning of any Apollo mission yet.