All language subtitles for Apollo 13 What Went Wrong

Apollo 13 was supposed to be the third

manned moon landing to gather important

science on a unique part of the moon.

What NASA got instead was a life and

death rescue mission, forcing them to

attempt to save three astronauts

stranded in a heavily damaged spacecraft

on a trajectory that would miss Earth by

thousands of miles. This is Apollo 13.

We've got one more item for you when you

got a chance. like

it tried to reset and

field problems like a lot of

instrumentation. Go ahead. Oh, here's a

problem. Apollo 11 had proven that we

can put people on the moon and Apollo 12

had done so accurately. Apollo 13's

mission was to use those lessons learned

to put astronauts on a specific region

of the moon, the Fra Maro crater. This

mission would have significantly more

emphasis on gathering science and

geological samples than the previous

missions as the crew's training could

focus more heavily on gathering science

rather than just largely focusing on

flying the spacecraft to the moon.

Because of this, the selection of the

landing site on the moon would be more

important than the last two missions.

Apollo 11's selection of landing sites

had to be heavily restricted in order to

keep the spacecraft in a free return

trajectory. This was desirable because

the spacecraft would already be on a

path towards Earth if anything went

wrong. Apollo 12 was the first to step

out of this free return trajectory,

which opened up more landing sites.

Apollo 13's goal was to do that maneuver

sooner. This would open up the Fromaro

landing site, but at the cost of making

this mission considerably more

dangerous. The primary crew for this

mission was supposed to be Jim Lovel,

Fred Hayes, and Ken Mattingley. Plans

would have to change fast, though, as

just 6 days before the launch, one of

the backup crew, Charles M. Duke, would

fall ill to the Reubella virus. This

would also expose both the primary and

the backup crews to the virus. Blood

samples from the astronauts would show

that both Loville and Hayes had an

immunity to Reubella, likely from being

previously exposed, so they were not at

risk of falling ill. John Young and Jack

Swagert of the backup crew also had this

immunity. Mattingly, however, did not.

The incubation time of Reubella meant

that if he did come down with the

disease, it would be when they were

scheduled to be in lunar orbit above the

moon, possibly when Mattingly was

supposed to be alone in the command

module. Replacing the entire primary

crew with the backup crew wasn't an

option, as Duke would have still been

symptomatic at launch. Delaying the

mission until the next launch window 28

days later also wasn't an option because

of the expense involved. With a rapidly

upcoming launch window, the decision was

made just 3 days before launch to

replace Maddingley with Jack Swagard.

The crew would be launching on the

Saturn 5 rocket, a design that had

proven itself over the last two

successful moon landings. This one,

designated AS508, would have a weight

just over 6.5 million pounds, making

this at the time the heaviest spacecraft

ever launched. 5 million of those pounds

are just in the first stage alone. On

the 11th of April, 1970, the crew would

enter the rocket on pad 39A at Florida's

Kennedy Space Center for its 2:13 p.m.

launch, unaware that they would not

reach their destination. 10 9 8 Ignition

sequence has started. 6 5 4 3 2 1 zero.

We have commit and we have liftoff at

213. The Saturn 5 building up to 7.6 6

million pounds of thrust and it is clear

the tower. This is mission control

Houston. We appear to have a good first

stage at this point.

13 Houston go at 30 seconds.

Roll complete and we're pitching. Roger

that. Standby for mode one

bravo. Mark one bravo command. And the

booster engineer reports we're now

through the region of maximum dynamic

pressure and we'll go.

13 Houston standby for mode one Charlie.

Mark your one Charlie. Mark one Charlie

and 13 you're go for staging. Go for

staging for EDS

[Music]

manual. There's no ignition.

Roger.

[Music]

Power. The Saturn 5's first and second

stages are powered by five liquidfueled

engines, which gives the rocket some

redundancy if one of them were to fail.

This would be the first significant

malfunction Apollo 13 would have to

endure as the central engine

unexpectedly shuts down. Even though an

engine had failed on the second stage of

the rocket, the mission was still a go.

13 Houston, trajectory is good, thrust

is good. Roger. The remaining engines

could still use all the fuel left in the

tanks, but they would be dragging around

a dead engine. So, they would be

slightly short of their expected speed

once the stage finished its burn. And

Level reports that the guidance system

is correcting the small errors and for

ignition Houston.

Roger that, Jim. Thrust looks good. The

second stage did its job by burning for

34 seconds longer than planned to

account for the lost engine. It's now up

to the third stage to make up the rest

of the velocity and put the spacecraft

into orbit. The third stage would burn

for around 2 minutes and 40 seconds, 9

seconds longer than originally planned.

The longer burns on both stages were

enough to overcome the lost energy from

the engine failure. After reading the

velocity, Apollo 13 was just 1.9 ft per

second slower than expected. And the

flight dynamics officer says at first

glance, we look good on the orbit. The

spacecraft had entered its planned orbit

around Earth at 100 nautical miles,

traveling

25,566 ft per second. Apollo 13 is now

traveling 21 times faster than a bullet.

The astronauts will use this opportunity

to calibrate their navigational and

scientific instruments to their new

environment in space in zero gravity.

This also gives the third stage engine a

chance to cool down and regain the

pressure on its tanks before its next

firing to get it to the moon. After one

and a half orbits, Apollo 13 begins its

trans lunar injection burn. You are go

for TLI.

Understand. And just out of curiosity,

uh was that engine out uh to be some

more S4B fuel?

Uh the engine out did cause you to use

uh more S4B fuel. Uh about a 10-second

longer burn, but you're still going.

Okay. Thank you. This burn would bring

the spacecraft out of Earth's orbit and

put it in front of the path of the moon.

The trajectory was aimed at where the

moon would be in 3 days when the

spacecraft was planned to get

there. The spacecraft would be flown in

front of the moon and the moon's gravity

would swing the spacecraft back towards

Earth. This maneuver is known as a free

return trajectory. It's a free return

because they don't have to spend any

fuel to get back to Earth. This

trajectory was chosen for safety

reasons. Even if the spacecraft's main

engine was lost, the astronauts would

still return home. This decision would

become incredibly important in

determining the future survival of the

astronauts. The third stage would

continue its second and final burn,

launching the spacecraft to the moon. It

was mission critical that this stage

burned for just the right amount of

time. If they were too slow, the moon

would have too much influence on the

spacecraft once it got there, bringing

it too far from Earth to be captured. If

the spacecraft was too fast, it would

fly past the moon too quickly and not

allow it to point the spacecraft's

trajectory completely back towards Earth

once it leaves its influence. After the

burn was completed, the astronauts

measured how far off they were from

their planned speed and trajectory. And

13 Houston, the booster reports uh that

everything looks good with the S4.

Sounds good, Houston. Uh the ride was uh

very nominal. We had a little vibration

though during most of the run.

Okay, we copied your call on that, Jim.

Okay, uh Joe, uh the discy read uh

35560 and delta VC was minus 3.0.

They're now traveling

35,560 ft per second, just 3 ft per

second higher than anticipated. Oh,

Roger. You can't ask for much better

than that. Uh they had just entered

their free return trajectory. They would

now prepare for a maneuver that needed

to be just as precise as the last. This

is mission control. We're now at 2 hours

54 minutes with the crew preparing for

the CSM

uh separation from the S4B, the

subsequent docking with the lunar module

and the ejection of the uh LMAN command

module from the Saturn third stage. Jack

Swagger would be flying this by hand.

[Music]

Telemetry data here on the ground

indicates that the spacecraft has

separated from the

S4B. Astronaut Jack Swagert at this time

would be in the commander's couch, the

lefth hand couch at the controls of the

spacecraft during the transposition and

docking maneuvers. Swagert now needs to

flip the command module around to line

it up with the lunar module.

That's quite a bang, Joe. We're

separated. We've pitched around about

60° now.

Okay, we got the uh flaw panels. One of

them's out front now.

Awesome. Swagger then uses the hand

controllers to bring the two spacecraft

together. A target is visible on the

lunar module that can be lined up with a

reticle inside of the command module,

similar to a red dot site. This way both

vehicles can be easily lined

up. A probe on the top of the command

module will lock inside of the lunar

module once they're properly

docked. The probe will bring the two

spacecraft together and automatically

secure them with latches.

[Music]

Now, preloaded springs would separate

the lunar module from the third stage,

and reaction control thrusters would

continue to pull them apart. The crew

would wait to see the third stage

floating away, and then they would radio

mission control to send signals to the

stage, which would fire thrusters and

remotely move it further away from the

crude modules. Mission control would

command the third stage into a

trajectory that would crash into the

moon. This was done on purpose so that

probes already landed on the moon could

detect the impact from the stage and

collect data from a known mass hitting a

known place at a known speed. This would

provide valuable information about the

moon's composition and what's underneath

its surface. The crew was now prepared

for their 3-day journey to the moon.

This break in the action gave the crew

that time to focus on slightly less

immediately life-threatening tasks like

Earth photography. Roger. We're at that

stage now where we're going to take some

Earth weather photography. If you're

standing by, I have the camera aimed at

the Earth right now and I'll give you a

mark uh when I take this first picture.

Roger. Uh we copy, Jim. We'll be

standing by for the mark. Okay, Houston.

3 2 1 Mark.

Roger. Copy. A photograph of Earth would

be taken every 20 minutes so that the

movement of the weather can be observed

when the images are stacked on top of

each other. 11 would be taken in total.

The command service module will use its

RCS thrusters to force the spacecraft

into a slow roll. This is so that no

part of the spacecraft is exposed to the

sun for too long and it would even out

the heating effects over the whole

spacecraft. This maneuver was called

passive thermal control or PTC. With the

spacecraft set up for its three-day

journey to the moon, the crew could

catch up in some much needed sleep.

Hello, Houston. Houston 13. Good

morning, 13. This is Houston. How are

you? Radio Mountain clearly.

And I have a small flight plan update

for you sometime a little later on when

you're ready to copy. There's uh no big

deals in it. and uh 13 Houston, we'd

like to verify that you cycle the O2

cryofans. We saw the H2, but we didn't

see the O2 get stirred up. In zero

gravity, the contents of superc critical

tanks would sometimes separate out into

portions of different density. If a

region of high or low density was picked

up by the sensor in the tank, it would

give off a false reading and set off

alarms. Because of this, the contents of

the super critical tanks had to be

stirred with fans in order to get an

accurate reading of the tank's real

pressure.

Uh yeah, Joe, we did. And uh kind of

looked like we might have had a little

stratification cuz right after we put

them on, we had a a cryop press light.

Okay. ECOM told me that might happen and

he was

right. Okay. At uh 23 hours, the total

RCS is one

121. Uh and the cryoss are as follows.

H2 tank 1

83%. H2 tank 2

86%. O2 tank 1

87%. O2 tank 2

87%. Over.

You forgot. We'd like to hear what the

news is. Okay. There's not a whole lot

to it. Um, okay. Let's see. The Beatles

have announced they will no longer

perform as a group. The quartet is

reported to have made in excess of a

half billion dollars during their short

musical career. However, rumors that

they will use this money to start their

own space program uh are false.

Hey, we can borrow some. Okay. Uh some

truck lines are being struck in the

Midwest and the school teachers have

walked off the job in

Minneapolis. Uh, today's favorite

pastime across the U. Uh-oh. Have you

guys completed your income tax?

[Applause]

How do I apply for an extension?

Louisville makes a joke about forgetting

to file his taxes and needing an

extension, not realizing that that is

the exact situation that Jack Swagard is

actually in.

Uh, I got a Hey, this that ain't a funny

kind of things kind of happened real

fast down there.

I I do need an extension.

I didn't get mine filed. I'm really

serious. Would you You're breaking up

the room time in a We'll I may be

spending time in I may be spending time

in another quarantine besides the one

that they they're planning for me. We'll

see what we can do, Jack. We'll get with

recovery and see if we can get the uh

the agent out there in the Pacific when

you come back. Uh uh Houston, this is

13. Is it is it true that Jack's income

tax return was going to be used to buy

the asset fuel for the Well, considering

that he's a bachelor and hasn't got that

deduction to take. Yeah. Hey Joe, I'm

glad you brought that up because I was

really serious about that. And Jim

McDivet says, "Yeah, now that you

mentioned he forgot to fill the asset

stage, should give you very good

performance on descent. You should have

a lot more hover time, huh? That's

right.

This is Apollo

control. 27 hours 20 minutes ground

elapse time. The crew rather quiet

during this period. Still in the passive

thermal control barbecue

mode. Velocity now

4,991 ft per

second. coming up in uh slightly over 20

seconds on uh the midpoint in

distance and at which time the uh

spacecraft will be equally far from the

earth and from the

moon. The distance at this time will be

uh

128,880.5 statute miles coming up Mark.

continuing to leave the circuit

live as we anticipate uh further

discussions and later on today the

midcourse correction burn number

two which will take Apollo 13 out of the

free return

trajectory into the so-called hybrid

trajectory which would not necessarily

return to the vicinity of the Earth. The

closest approach would be something in

the nature of 40,000 miles coming back

from the non-free return

trajectory. Just passing comment Joe.

We're having lunch right now and I just

made myself a hot dog sandwich with

ketchup. Very tasty and almost unheard

of in the old days. Uh that's correct.

13. As I recall the flight plan, you're

supposed to put mustard on the hot dogs

and not ketchup, but uh I guess we'll

overlook that.

[Applause]

Right. Apollo 13, Houston.

Go ahead, Joe.

Hey, uh you got a new Capcom on now with

the black crew and we have about three

items to give you, Jack.

Uh, I'm going to give you uh some high

gain antenna angles for TV and the rest

is just information. Uh, and uh the last

items for Jack. Jack, uh, preliminary

indications are that you can get a

60-day extension on your filing your

income tax if you're out of the country.

That's good news. I guess I qualify.

Yeah, we were just looking at the map

and you're south of Florida,

so you're not in the country now. Jim,

Houston, you're looking good down here.

Go for the burn. The crew had just

received the go message for their

midcourse correction 2 burn. This burn

would bring the spacecraft out of its

safe pre-return trajectory and put it

into a hybrid trajectory closer to the

moon's surface. If the spacecraft were

to not make any burns after this one, it

would miss Earth by thousands of miles

on its return.

[Music]

After their short burn, they were now on

the correct trajectory towards the Fraro

crater and away from Earth. With this

day of work complete, they could now

begin their second rest period of the

mission to regain some sleep.

Houston, Houston, fin.

Good morning, 13. You're early.

Uh, so I just thought we'd wake you up

and uh we're uh we're awake and uh

getting the uh spacecraft ship shape and

see uh roger. Spacecraft's in real good

shape as far as we're concerned, Jim.

We're board to tears down here. Uh we do

have a few little items for you like a

P37 update and a couple of flight plan

updates. Uh but there's no rush about

them. Over. And it might be interesting

that just after we went to sleep last

night, we had a master alarm and uh it

really scared us and we rolled over the

cockpit like a wet noodle.

Sorry, it wasn't something more

significant. Uh uh I've also got a a

procedure for you on that H2 tank. Uh

simple thing after you get done stirring

up the cryos. The pressure inside of the

spacecraft super critical hydrogen tank

2 had been fluctuating enough to set off

pressure alarms and startle the crew.

This was an issue they would begin to

troubleshoot when a new issue arose.

I've got a consumables update for you,

Jim, if you're ready for that.

Ready to copy. Okay. As of 47

hours, RCS total 10 niner

6 and the H2 uh they gave me the H2s in

percent

uh 76%.

And on the O2 we have

81%. However, we show the O2 Tank 2

reading offscale high. Now, we're quite

sure it's a uh it's a sensor failure.

We'd like you to verify it with your

onboard reading.

Okay, stand

by. Uh Joe, we confirm uh our gauge

reading is uh the number two attack is

no scale high now, but that just tells

me that uh it was okay when you first

went this morning. Uh we we verify that

at uh 4645 we had

82%. And uh apparently uh uh when he

stirred the uh the cryos

uh the sensor broke. Now not only is

their hydrogen tanks pressure

fluctuating, but the quantity sensor for

oxygen tank 2 was reading offscale high.

Oxygen tank one sensor seemed to be

working. So that one could be used to

get a general idea of the pressure in

tank 2 as long as they're used evenly.

This moon landing is still very much a

go.

13.

Go ahead. All right, Jack. Uh, one uh

one thing we'd like to have done uh

sometime soon is to have you cycle the

cryo fans in O2 tank 2 one more time. We

like to see if we can get that sensor

back.

Okay. Go on. O2 tank two fan on down.

Roger.

follow 13 Houston.

Go ahead, Joe. We're ready to have the

O2 tank to fan off it. Thank

you. Okay. Doesn't look like it got it

back, huh? Uh, no it doesn't, Jack.

Apollo 13, Houston. Go ahead. Uh, roger

13. Uh, because of the, uh, O2 take 2

quantity sensor dropout, u, uh, ECOM

wants to keep a little closer track of

the, uh, of the cryo quantities. And

he's going to be asking you to stir all

the cryotanks at slightly more frequent

intervals than um, than have been

planned. And the first time is now. And

we'll be calling you probably every five

or six hours except during sleep periods

and uh and high activity periods. We'd

like you to do it now. Over.

[Music]

Okay. We'll start a stir now. Thank

you. And 13 Houston for your

information. A normal 1 minute or so

stir would be They would begin to

regularly stir both of the oxygen tanks

to get a more accurate read on what was

left in them. This would help them infer

how much was in the tank with a broken

sensor. The command module wasn't alone

in its super critical tank issues. The

lunar module's helium tanks had been

tested on the ground and had shown some

signs of poor insulation. Ground control

wanted a reading of the pressures on

board inside of the lunar module. So,

they radioed the crew to enter the lunar

module 3 hours earlier than planned.

Okay. Uh, the LMP is entered.

Roger.

Okay. And it just flickered down to 710.

It's going to flickering between 710 and

720.

Roger. 710 to 720.

Our super critical helium pressure

reading was 720 lb per square inch. Uh,

a very desirable

number. We're at 54 hours 53 minutes now

into the flight.

Apollo 13 at

176,171 nautical miles away from Earth.

We're standing by now for receipt of

television. The crew deploys the high

gain antenna in order to send over a

video signal that would be broadcasted

to people's televisions. The crew would

need to stop their passive thermal

control role in order to line up their

antenna with Earth. The success of the

previous two moon landings gave the

public a false impression that these

missions were now routine and didn't

pose a significant risk to the

astronauts. As such, the media largely

felt it wasn't in their interest to

cover this mission. No TV networks would

show Apollo 13's broadcast. The crew

would attempt to give a good show

regardless of the public's apparent

disinterest.

Okay, Houston, we'll try to pick you up

on high gain.

Apollo control Houston standing by now

for receipt of television transmission.

[Applause]

We're now re receiving a transmission,

television transmission.

Okay. 13. We got on TV.

Uh the limb, as you can see, it uh

looked pretty clean. And I found a

couple of loose washers about it. And

the a little plastic cap off the

sequence camera had come loose. And I

found it uh lodged over by the ED

panel right under uh Jeff. Now he's

actually standing on a what looks to be

a can here. And uh for the sake of all

the people back there uh housed inside

this can is the u the lamb mass engine

or hopefully you can see my hand resting

on top of right

now. The engine that uh we used to get

off of the

moon and I guess this uh an app

description for this device would be a

fish

scale. And you can see I'm weighing

myself right now. and uh says a way

actually less than zero right now. Guess

it's calibration in too good. That'll be

the day.

Okay. What I have out now, Jack, is

uh Levo, which is also been shown

before. It's a head garment uh for

wearing out on the

surface. And I I'm bringing gems out

here to show a couple of mods.

One problem before is that uh the cast

of characters out on the surface haven't

been able to be distinguished apart very

well. So, not only Jim Suit has some red

stripes on it, but as you can see, his

lema also has a a red

stripe. And uh now you can see one other

mod too here, Jack, which I hadn't

really seen myself before. Uh I guess on

12 Pete now had uh commented about the

uh commented about having trouble with

sunlight in the eyes. So on our levers

they have put on a new center section uh

which you can pull down and use uh sort

of like a baseball

cap. Okay, Jackson fixed up on

What uh Fred is opening

up is a drink bag that we place inside

of our neck ring that uh will allow us

to drink while we're on the lunar

surface. Uh they feed an Al did not have

that in Apollo 12 and they consequently

got very thirsty. Uh but we hope to

alleiate that situation by having uh our

own little uh bag of water which uh with

very little effort we can uh have a sip

or two while we're looking around and uh

doing our geology work.

So, uh, if you hear any funny noises,

uh, it's just, uh, probably the drink

bag.

Okay, Jack. I'm looking out the uh right

window now and uh not too far off in the

distance now. You can see the uh the

objective. And I'll zoom in on it here a

little and see if it brings it in

better. It's actually beginning to look

a little bigger now. Uh you can see

quite distinctly some of the features

with the naked

eye. And uh so far I guess I have to

even agree with Jim that it's uh still

looking pretty gray uh with a white

spot.

Okay, Fred, we're getting a good uh

picture of your destination there.

You're looking now at our uh probe that

we place uh on the nose of uh Odyssey.

Uh it's a very heavy thing, but of

course in zero gravity, it uh weighs

nothing and it's much easier to move

around. As a matter of fact, both uh

Fred and Jack commented as many people

in the past have of how much bigger the

spacecraft appears. uh in actual flight.

Uh when you have such ease of movement

compared to our simulators which make

training rather

difficult. Okay, we're seeing a good

picture of the probe there, Jim. And uh

looks like the characters shaved before

the show this time.

Well, Fred said he had to keep up his

TV.

Yeah, that may be uh my first and last

time. Now, Jack, it took Fred 1 hour to

shave.

Okay, Jim, we're seeing a tape recorder

now. And uh just by the way, how long

you expect to keep the TV on this

evening?

Well, whenever

you stand by one.

Yeah, I got him with the uh Kevin Reaper

valve in there,

Jack. Every time he does that, our

hearts our hearts jump in our mouth.

Okay, Jim. Uh it's been a real good TV

show. Uh we think we ought to conclude

it from here now. Uh, what do you think?

Roger sounds good. And this is the crew

of Apollo 13. Wishing everybody there

a nice evening. And uh, we're just about

ready to close out our inspection of

Aquarius and get back for a pleasant

evening at Odyssey. Good night.

Thank you. 13.

13, we've got one more item for you when

you get a chance. We'd like you to uh

stir up your

cryotanks. In addition, I have shaft and

trion okay for a look at the comet

Bennett if you need it.

Okay, stand by.

[Applause]

[Music]

[Applause]

Gohead. We've had a hardware. I don't

know what it was. Okay, Houston, we've

had a problem here.

This is Houston. Say again, please.

Yes, sir. Uh, Houston, we've had a

problem. We've had a main Bus.

Roger. Main B undervolt. We got a main B

undervolt. Okay, Flight, we've got some

instrumentation finds. Let me Let me add

them up. Roj. Okay, stand by 13. We're

looking at it. We may have had an

instrumentation problem. Roj. 55 hours,

54 minutes, and 53 seconds into Apollo

13, Oxygen Tank 2 explodes, ripping off

the side panel of the spacecraft and

severely damaging the equipment inside.

Ground control could only see the radio

telemetry coming down from the

spacecraft and had no idea of the

immediate damage that was caused by the

explosion. What they could see, however,

only gave them questions. The numerous

warnings and alarms that ground control

was seeing to them might be a false

alarm caused by erroneous sensor

readings, just like the pressure sensor

earlier in oxygen tank 2. This is why an

instrumentation problem is called out as

the first possible explanation to the

alarms. They would begin to put together

the pieces to figure out what really

just happened. The spacecraft's

electrical system is connected to fuel

cells. These fuel cells take in oxygen

and hydrogen from the spacecraft's tanks

and react them together. This would

generate the electricity needed for the

spacecraft and the astronauts could use

the water that was a product of the

reaction. The astronauts needed to rely

on these fuel cells to generate

electricity and water throughout the

flight as carrying a separate water

supply and batteries would have

significantly increased weight. The

service module is equipped with three of

them. The fuel cells are connected to

the spacecraft's electrical system

through electrical buses which

distribute the power to the other parts

of the spacecraft. The fuel cells

generate a direct current which go into

two direct current main buses. Both

buses are connected to their own

inverters which power separate

alternating current buses, allowing

alternating current devices to also be

powered. This is a redundant system that

the crew will now need to take advantage

of. Fuel cells one and three, which were

taking oxygen from the now destroyed

oxygen tank 2, significantly drop in

voltage. Main bus B at the time of the

explosion was only connected to fuel

cell 3 which is now not producing

electricity. This throws up a main bus B

undervolt warning which the crew and

ground control can see. Right now the

astronauts are relying on one dying fuel

cell fuel cell 2 in order to generate

the entire spacecraft's electricity. It

won't last long. A hardware restart

followed by a main bus B undervolt are

the first indications to ground control

that something had gone wrong. And we

hit a pretty large bang. associated with

the caution and warning there and the

interior. We're starting to go ahead and

button up the tunnel again. The fuel

cells drop in voltage started a cascade

of events alongside the explosion.

Multiple sensors, including the ones

inside of the cryogenic tanks, were

being powered by the now dead main bus

B. These sensors would lose power and

drop out as a result. The spacecraft's

guidance control system and computers

would also restart. And uh Houston, we

had a restart on our computer. We have

pings light and uh and restart. Reset.

Roger. Restart and ping light. Restart

on reset.

Okay. AC2 is showing zip. I'm going to

try to reconfigure on that. Jack

Ecom, you were seeing any AC problems.

Looks like a lot of instrumentation

problems there. Go ahead. That's for

flipping the fuel cells around flight.

Well, let's get some recommendation

here. S if you got any better ideas.

Yeah, we got a uh main bus a undervolt

now too. Sean, main A undervolt. The

spacecraft's other bus, main bus A,

start showing signs of weakening from

losing one of its fuel cells. It's

reading about 25 and a

half. Main B is rating zip right now.

Flight econ. Go ahead. He's got U fuel

cells one and three are offline. We've

got main A volts. We have no main B

volts. have an attempt to re uh

reconnect the fuel cells. Fuel cell one

to main A, fuel cell

uh three to main B. Okay. Now, is there

do we have instrumentation problems?

Well, we lost a It does appear we've

lost AC bus 2 voltage. Main B is reading

uh 4 volts and that effectively takes

AC2 away from us. Okay. 13, Houston,

we'd like you to attempt to reconnect

fuel cell one to main A and fuel cell 3

to main B. Okay, Houston, I'm showing I

tried to reset and uh fuel cell one and

three are both showing uh gray

flags, but they're both showing zip on

the flows. The crew attempts to reset

the fuel cells into the same

configuration, which results in no

changes. Roger. Flight ECOM. Go ECOM.

Let's reverse a configuration request.

Okay, but wait a minute. We got a good

main A bus. Let's make sure that

whatever we do doesn't screw up main A.

Fuel cell 2 is on main A flight. I'm not

going to ask to change that. Okay. What

do you want to do? Let's try to put fuel

cell one on main B, fuel cell three on

main A. We use the other uh sensing

circuitry. We're not going to touch fuel

cell two flight.

Okay. But if we got any problems in the

system, I want to make sure that we

don't blow the voltage off main A. Then

we're not going to be able to see

anything. You got can we review our

status here sigh and see what we've got

from a standpoint of status. What do you

think we got in a spacecraft that's

good? Main bus A is reading 25 volts.

Okay. Main A and that's reflected by the

fact uh fuel cell 2 is putting out uh 53

amps which is just about the most it can

and keep our voltage up. Okay. So that's

bonafide. AC bus 2 is zero which is

reflected by the fact we lost main B.

Flight econom go ecom. Okay, let's get a

read out on a couple fuel cell pressures

here. Okay. Uh, fuel cell one, N2

pressure, fuel cell 302 pressure. We're

reading uh 0 N2 pressure and fuel cell

one and 13 PSI on fuel cell 302

pressure. 13 Houston, we'd like you to

verify a couple readings for us. We'd

like the nitrogen pressure on fuel cell

one. We need the oxygen pressure on fuel

cell two.

Okay. Nitrogen on one and oxygen on two.

Is that correct? Negative. Oxygen on

three. Okay. Now, are we using RCS now?

That's affirmative. We're going to have

to switch them thrusters over to main A

to hold the attitude here. Okay. Uh, how

much RCS we using? Oh, we've used um Oh,

yes. 25 lb.

Okay. Give me a minimum fuel usage

configuration that'll keep me out of the

garage. The RCS thrusters have been

firing since the explosion, attempting

to keep the spacecraft in an attitude

that has radial contact with Earth and

that could avoid gimbal lock. This would

eventually give the spacecraft enough

velocity to begin deviating from its

planned trajectory. I tell you, go tell

me the limb heater currents become

essentially static. Roj, let's solve one

problem at a time. come back to me later

on in a

and uh two Baker which is three oxygen

says 6

two Baker says 6 and say again the other

one uh fuel cell one nitrogen reads zero

roger zero both fuel cells are well

under their normal operating pressures

this is a hint to ground control that

something might have gone wrong with the

super critical tanks providing the gas

but it might also just be another sensor

error go ahead

Uh why don't we try leave fuel cell 2

alone and just make sure that one and

three are disconnected from both buses

and make sure that there's abs won't be

any load on them at all and let's see

what happens to those

cells. Okay, very what do you want to

do? Open circuit fuel cell one and

three. That's very important.

Okay, Capcom, let's recommend we open

circuit fuel cell number one and number

three and leave fuel cell number two as

is.

Okay, one and three. Open circuit two as

is. And earlier got a report from them

that uh one and three were reading gray

but zero flow. Yeah, Capcom, let's amend

that. ECOM from flight ecom. Why don't

we just open circuit one and make sure

that we don't have any problems getting

that back onto the bus. Okay, just watch

it for a while before we make any

further moves with three. Roger. Okay,

Capcom, let's just open circuit one of

those right now. 13 Houston, we'd like

you to open circuit fuel cell one. Leave

two and three as is.

Okay, I'll get to work on that. Ground

control hopes to alleviate any problems

the fuel cells might be having by

disconnecting them from the rest of the

spacecraft's electrical systems. Right

now they don't know what's going on with

the spacecraft and out of caution decide

to only disconnect one in case they

start getting more issues from them. And

uh Jack uh our O2 uh quantity number two

tank is zero. Did you get that? O2

quantity number two is zero. That's AC.

Okay. The gauge that was previously

acting up now shows there's nothing in

the tank. Louisville realizes that the

gauge is being powered by the now dead

AC bus 2. So he disregards that reading

and then immediately makes a startling

discovery. Yeah, that's that's a good

thing to see. And it looks to me looking

out the hatch that we are venting

something. Crew thinks they're venting

something.

We are we are venting something out into

the uh into space. Roger. We copy your

venting. The spacecraft had been venting

something since the explosion. Okay,

let's everybody think of the kind of

things we'd be venting. GNC, you got

anything that looks abnormal in your

system? Negative light. Okay, fuel cell

one, you just wanted to off the line

now, Jack. Is that right? We just wanted

you to open one.

Okay, she's off the line. Okay, now

let's everybody keep cool. We got the

limb still attached. The limb

spacecraft's good. So, if we need uh to

get back home, we got a limb to do a

good portion of it with. Okay, let's

make sure that we don't do anything

that's going to blow our CSM electrical

power with the batteries or that will

cause us to lose the main or the fuel

cell number

two. Okay, we want to keep the O2 and

that kind of stuff working. We'd like to

have RCS, but we got the command module

system, so we're in good shape. If we

need to get home, let's solve the

problem, but let's not make it any worse

by guessing.

Apollo control Houston. Um this rapid

exchange of conversation you've heard u

may the main B bus uh is off the

line. Uh fuel cells one and three also

off the line. Uh fuel cell 2 is

presently on the line. We now show 13 at

an altitude of

178,643 nautical

miles. We're at 56 hours 12 minutes into

the flight. Okay. Can you tell us

anything about the venting? Uh, okay.

Where it's coming from. Uh, what window

do you see it at? It's coming out of

window one right now, Jack. Flight. Go

ahead. Uh, I think the best thing we can

do right now is start a power down.

Okay. Uh, let's go down uh the emergency

1-5. Okay. What do you want to go to?

Uh, power down. Give me the page. Uh,

emergency 1-5 flight. We'll go down uh

try to get a delta of 10 amps reduction.

Ecom, do you want to go through that

again? What do you want to power down

to? I want to power down uh a total of

10 amps. White, a total of 10 amps.

That's fine. Okay. Capcom, we'd

recommend emergency power down checklist

1-5. We want a power down a total or a

delta of 10 amps from where we are now.

Flight GNC. Go GNC. Can we afford to do

a PTC first and then we shut off all of

that stuff with no problems? Uh why you

think you're going to have a thermal

problem here? Well, we could have uh if

we stay there too long. Okay, we'll run

into that one later, Buck. Okay, I want

to get our major problem sorted out now.

You want I still want 1-5 down to 1-5

powered down delta 10 amps. Scap. Okay,

13, this is Houston. We'd like you to go

to your GNC checklist. The pink pages

1-5. Do power down until we get a delta

of 10 amps. Over flight econ.

Okay, I need one thing right now. He's

powering down. hangs down to 401 amps

total spacecraft. I'd like to get uh my

AC2 bus back so I can look at O2 tank 2

pressure. I I have no insight into that.

Okay, let's get uh I guess we can put

inverter

uh three to main

A2 and let me ask you before you do

that, would you like to make sure you

got all AC load you don't need isolated

from the bus?

Nah, let's not do that right now.

Flight, I think we're in good shape that

way. The main is up high enough where it

can handle the inverter. Thing that

concerns me is starting is throwing

equipment. We We had a problem. We don't

know the cause of the problem, right? I

I've got a feeling we've lost two fuel

cells. I hate to put it that way, but uh

I don't know why we've lost them. It

doesn't all tag up, and it's not an

instrumentation problem, the best I can

tell right now.

Okay. And uh something is uh giving us a

rates jack both in pitch and roll. So I

suspecting that maybe it's whatever it

is that's vending back there. I've had

to use uh direct in order to stabilize

this. And as soon as I do, we're

starting to pick up rates again. Can you

pick up any jet? Sorry. Standby.

Whatever was venting seemed to be

actively pushing the spacecraft around,

explaining the constant RCS thruster

firing. Swagger would have to use the

manual controls multiple times in order

to counteract the venting. What

direction are your rates in Jack?

It's negative pitch and negative roll.

That's further. What's firing now? You

got something firing? Well, we've seen

quite a bit of thruster activity. Okay,

I guess this kills a PTC, too, because

we're not going to get into PTC as long

as we got something venting. The gauges

that were knocked out by the power

outage are now a concern for the ground

crew. They could see the main bus B that

was powering them is now offline, but

main A still works. They would need to

connect the working bus with the now

offline sensors. Flight econom. Go ECOM.

Uh, I got a little correction. Let's put

inverter one on both AC buses, please.

One on both AC. Confirm. So, I can get

some uh AC bus power back so I can have

some insight into my uh AC bus 2

telemetry, especially my crows. Maybe

the vending may be coming from that. You

want to put inverter one in both AC

buses, ECOM and Capcom, let's do it. The

idea was simple. One inverter could

power both buses, and they could use

that to power the gauges on AC bus 2

that are now offline. This would supply

power to the gauges inside of the

cryotanks, and that would allow the crew

to read the tank's real pressures. 13

Houston, uh, we need to get some more

instrumentation up. We'd like you to put

inverter one on both AC buses. Over.

Okay, you got inverter one on both AC

buses now. Telmu and control from

flight. Go flight. Will you take a look

at your pre-launch data and go through

your system? See if there's anything

you've got that may have started vending

here. Roger. Flat. Okay. And I want to

report in that in about the next 15

minutes. Quick look type stuff. Okay.

Flight photo. Go photo. We're definitely

seeing a vent in the data. Okay. And

have you got any thrusters firing? We're

looking at that C3 thruster flight that

looks like it stays on most of the time.

Well, can we turn them all off and see

if we still got the rates or any build

up in rates? Well, the rate that we're

seeing is opposite to the direction of

that thruster. So, if anything, it's

just trying to hold and not quite up to

it. Okay. But he's been trying to

counteract the rates with

direct. He's been getting a negative

pitch and a negative roll. Okay. But he

asked if we were getting some thruster

firings that were not being made by him.

I'll tell you what, uh, GNC, can you get

somebody in the back room to try to

figure out what the equivalent delta V

is we're getting so that we can see if

we can backtrack to see if we can figure

out what's venting. You come from

flight. What did uh, okay, you got two

good AC buses. What did all that tell

you now? It it tells me that

uh, well, just give me about two more

minutes, fly. Okay, take your time.

Okay, 13. Uh we've got lots and lots of

people working on this. We'll get you

some uh dope as soon as we have it and

you'll be the first one to know. Yeah,

the uh crew did report they removed fuel

cell 3. They open circuited it also,

didn't they? I don't believe so. Fuel

cell one and fuel cell 3 should be open

circuited. Uh we just had our last call

for fuel cell one open circuit and uh we

left fuel cell 3 as it was. Well, let's

take this open circuit fuel cell three.

Open circuit fuel cell 3. Get it off the

bus. We got to worry about getting some

power on main B to get the pressure back

up. No two tank one. Roger. Flight ECOM.

Go ECOM. Let's have him isol isolate the

search tank also and save it. We use the

cryo as much as we can. Uh, say that

again. Let's isolate the surge tank

command module. I don't understand that

sign. I don't want to I want to use the

cryo as much as possible. But that would

seem to be the opposite. If you want to

keep the fuel cell going, the surge tank

is an oxygen tank located inside of the

command module. The crew needs to use

this for re-entry with Earth after

separation from the service module. In

emergency cases like this one, it can

supply oxygen to other parts of the

spacecraft, like the fuel cells to keep

them alive, which is currently doing. An

incredible amount of foresight is used

to make the call to isolate the tank in

order to save the oxygen for re-entry,

but ensuring the imminent death of the

spacecraft's only remaining source of

electricity. The fuel cells are fed off

the uh the tanks in the service module

flight. The search tank is in the

command module.

We want to save the surge tank and which

we need for entry. Okay, I'm with you.

I'm with you. Roger. Capcom, let's also

isolate the surge tank. Okay, you want

to isolate the surge tank. Yeah, O2

surge tank. Right. Yeah. What we're

really doing is securing our entry

systems right now. 13 Houston, we'd like

you to isolate your O2 surge tank. Over.

Surge tank off now. Jack, flight econom.

Go. Ecom. Okay, since O2 tank one

heaters are on main A and we've got them

off now, uh we'll be able to stay in the

5 amps uh temporarily uh for a manual

pressurization, let's uh have them turn

the heaters on manually. O2 tank one and

we'll watch the pressure tank one. A

heater is activated inside of oxygen

tank one in hopes of raising its

pressures and helping the fuel cells.

Capcom, we want to get cryo2 tank number

one heater on. Roger. We copy them and

uh we'd like to build up the pressure in

O2 tank one. So uh turn the heaters on

manually. We'll watch the pressure for

you. You can stand the 5 amps on main A.

That's we think so. Flight. Okay. Uh

we're going to get a main bus under

probably. Roger. Uh we realize that uh

we feel we can stand five more amps on

it. Okay. Uh he tanks on. Did you see

your 5 amp increase in current? That's

firm flight. Okay. 26.7 volts. Looks

good. We'll watch the pressure.

Flight ECOM. Go ahead. Ecom. Uh, I want

the fans on and uh O2 tank one. We're

not seeing a pressure increase. We can

stand it. You can stand it. That's fair.

Ground control can see the power is

being used by the heaters, but the

pressure doesn't increase in the tanks

like they were expecting. The cryofans

are activated to try to get a better

reading on that tank. 13 Houston. Uh,

we'd like you to additionally bring on

the fans in O2 tank one. And uh we can

stand the additional amperage on that.

Okay. Flight ECOM. Go ahead. Ecom. The

pressure in O2 tank one is all the way

down to 297. You better think about

getting in the limb or using the limb

systems. I'm going to have to power way

down. I don't know if I'm going to be

able to save the O2 for the third fuel

cell for fuel cell 2 rather. Tell me you

from flight. Go ahead. Flight. I want

you to get some guys figuring out

minimum power in the limb to sustain

life. Roger. Okay. Everything that

ground control tries to raise the

pressure in the working oxygen tank

fails. The gauges that they had powered

up in that tank are reading that it has

been rapidly draining since the

explosion. They begin to calculate how

long their oxygen supply will last under

these conditions. Uh Jack, looking

outside, the number of particles has

diminished greatly almost ceased now,

which indicates maybe what it was ving

has almost stopped.

Roger Jack. Thank you. We copy. Any more

suggestions on trying to pump up O2 tank

one pressure? No.

Uh, flight, we're going to hit 100 PSI

in an hour and 54 minutes.

That's the end right there. The command

service module's oxygen system requires

a pressure of at least 100 PSI to

function properly. If the oxygen

pressure goes below that threshold, the

fuel cells stop working altogether.

Flight from flight. Go ahead, slide.

Whatever planning you do, I want to do

assuming that we're going around the

moon and we're using the limb for

performing the maneuver because in the

present configuration, unless we get a

heck of a lot smarter, I think we're

wasting our time planning and using the

SPS. Okay, flight. So, I think all of

our return to Earth type planning should

be assuming the uh use of the lamb dips

and or

RCS and I think third priority down the

line should be CSM RCS. Okay. And I'm

assuming you'd want fastest possible

return.

Uh yeah, I think that's the case. Okay,

we'll we'll work on it from that

sideline flight. Should be no problem.

The flight director does not like the

idea of firing the service module's main

engine. They could tell whatever was

causing these issues came from the

service module, and its effects were

severe enough that firing the engine in

a now unknown state carried significant

risk. If the engine or parts of its

nozzle were punctured, the main engine

could now be another bomb just waiting

to go off. The difficulty of starting

the service module's engine and guidance

system in a now powered down state added

to the uncertainty. The safest possible

option was switching entirely to using

the lunar module. It has its own oxygen,

electrical, and guidance systems, and

most importantly, its own engine. Ground

control's new task was to use an

emergency protocol designed for the

failure of the service propulsion system

engine as a guide to power up and

maneuver the lunar module with the

command service module still attached.

Flight Ecom, go ahead. Ecom. Okay,

listen. There is a possibility that we

blew a O2 line in one of the fuel cells

and it's effectively manifolded there.

Of course, now I'm I want to shut off

one of the re the reactant valves to one

of the fuel cells, and that would be

fuel cell 3 since its O2 pressure is

gone. Now, fuel cell one's O2 pressure

is trying to stay up there at 45 PSI.

Maybe the problem is in fuel cell 3.

[Music]

That sounds like a good assumption right

there. Yeah, fuel cell 3 is lost anyway

as far as flight GNC. Go GNC. Turn

Charlie one thruster off. You want to

turn Charlie one off? Why? Well, it

looks like we're getting a lot of firing

out of for no reason. Okay, Capcom,

recommend thruster C12 off. Excuse me,

Fred. I'd like to butt in here a minute.

We'd like to have thruster C1 off. C1 is

off. ECOM from flight. You want to shut

off both reactant valves to fuel cell

number anyway. Flight. Okay. and the

inline heaters off in fuel cells one and

three, please. What we're proposing

supposing here, Capcom, is we may have a

had some problem in fuel cell number

three since that's the one that's

reading no O2 right now and we may be

losing our O2 through fuel cell uh

number three, the O2 manifold and as

much as they're manifolded together

commonly. Uh looks like the O2 and fuel

cell one and two seem to be trying to

stay up there.

and fuel cell three looks like it's the

oddball here. Capcom, let's close the

reactant valve to fuel cell number

three. Okay, close reactant valve to

fuel cell number three. And um you're

saying that one and two look okay? Well,

what it looks like looks like the

pressure is trying to stay up there. And

this is the best guess we've got right

now because we got to stop this O2 flow.

Okay, 13, this is Houston. And it

appears to us that we're losing O2 flow

through uh fuel cell 3. So uh we want

you to close the react valve on fuel

cell 3. It looks like fuel cell one and

two are trying to hold up. Okay. Most of

ground control's attention is focused on

stopping the remaining tank from losing

the rest of its breathable oxygen. They

tried shutting off the valves that lead

to the fuel cells in case the oxygen had

been leaking through them, among other

measures. What they didn't know is that

these attempts would be entirely futile

in stopping the remaining oxygen tank

from completely draining. The tank that

had exploded was located right next to

the now draining tank. And somewhere

within the pipe work leaning from that

tank, something had been jolted far

enough to break a seal or a pipe open.

The venting was the crew seeing their

own oxygen from the only tank left in

the service module. Flight GNC. Go DNC.

More jet reconfiguration to see if we

can hold the attitude. Okay. Like to

turn Charlie 2 off. Why are we

interested in holding attitude? If we're

not venting, why not drift for a while?

It'd probably be better from a

standpoint of thermal control anyway,

wouldn't it? Well, I think we'd like to

get into a control drift rather than

just some random thing like that. ECOM,

have you deduced anything? Have you seen

your uh reactant valves go off? Have you

seen flow cease?

You can't tell. Flight knew they were

open circuited and the pressure uh

still appears to be going down. Yeah.

Okay, flight, we have our checkpoint.

Okay, all flight controllers, I'd

suggest you start handing over because I

think a fresh team is probably going to

be thinking clearer. I think the rest of

us can continue working in some other

function in support of the new team

coming on. Okay. Uh, let me go back over

this again. We're heading over to Glenn.

I'd suggest the white team goes back and

starts going through the Dlog of the

data. In other words, let's see if we

can go back to the initial conditions

and work in that problem to see if we

can find out what happened and we may

find some better clues as to what to do

and let the French guys come on and try

to figure out where do we go from here.

The scheduled time for the ground

control crew switch over had arrived.

Although the currently serving white

team would have to run the incoming

black team through a lot of information,

having a fresh pair of eyes look over

the problems could help reveal other

issues they had missed. The white team

would continue to help troubleshoot in

the background. Ecom, I don't like the

way that O2 pressure is going down. If

you want to do something about these

other reactant valves, let's make up our

mind.

Go ahead. Okay. On the reaction for fuel

cell one, uh seems to me we have no

choice but to go ahead and do it. The

pressure continues to drop. Uh we're not

going to have anything left soon anyway.

So, uh it looks like the next best thing

to try is to go ahead and uh turn the

reactions off on fuel cell one. And

Houston 132 tank pressure number one is

less than 300 now.

Roger. Are we seeing that? We confirm

it. Yeah, we copy that. Tell them we're

debating shutting off the reactants on

one flight. Go ahead. The temperature is

the only thing we have. And is it

correlate? Pretty closely. You're saying

then that I'm looking at a valid

pressure in that tank and it's still

going down. That's what it looks like.

Therefore, therefore, we need to go to

fuel cell one and uh turn off the

reactants. Capcom, fuel cell one

reactants because because the tank one

is still going down. Pressure and temp

pressure going down. Temperature

confirms it. Okay. 13 Houston, we're

going to have to have you uh go through

the shutdown procedure on fuel cell one.

Our O2 uh pressure is going down as you

note and the temperature confirms it.

Okay, Jack. We're proceeding with a

shutdown procedure for fuel cell one

flight. Go ahead. Fine. Does the

temperature in tank 2 correspond to the

pressure reading? Let me see how close

it is. Fine. Fight. Go. temperature and

the pressure correspond. They're

verifying that the pressure is reading

right in tank two. That's right. Fine.

Tank two. Okay. Now, is it possible that

we still have that tank and it's good

and we could somehow get power on B and

use it? It's not likely. Flight not.

What's not likely, Clint? It's not

likely to be able to uh actually have

anything left in the tank.

You don't think so? I don't think so.

But let's we'll pulse that one, too. All

right. Let me get you a time. It look

like we've got on tank one here. All

right. Uh tell me your flight. Go fly.

Is there anything uh simple that we can

refer the crew to uh to get them

thinking about using the limb here? Have

you got anything in the checklist

paperwork to describe to them what your

intentions are? Negative. There's

nothing documented in contingency. We're

thinking about using the limb as

lifeboat. We have some procedures here

on the ground though. I'm sure you do.

What do they amount to? flying with the

tunnel open. Uh, roj. Uh, just a limb,

low power load supplying power to the

CSM.

Supplying power to the CSM. Yes. About 5

amps. Uh, to what? To their main bus.

Okay. Where? Well, main B is in bad

shape. We don't have anything on main B

right now. What's that power for? Tell

me. Just anything they might need for

Okay, Jack. It looks like O2 tank one

pressure is just a hair over 200. We

confirm that here. And the temperature

also confirms it. Okay. Does it look

like it's still going down? It's uh

slowly going to zero and uh we're

starting to think about lamb lifeboat.

Go ahead. Okay. Got an update on the

time. Look like we got about 18 minutes

until we get down to 100 PSI and that's

sort of the cut off point. All right.

But we're charging battery A. Well, that

doesn't mean much in 18 minutes though,

but we're doing all we can do. All

right. Uh, econ flight. Quite fine. Let

me try one more time. Is it possible

that if we got power to main B that we

could get tank 2 powered up and up in

pressure? We don't feel like that's a

possibility. We might conceive power. We

don't feel like we can get anything out

of tank two. Okay. Now, why is that?

Tell me why. I'm just because the

numbers we're looking at indicate that

it's essentially uh uh ambient. All

gone. Uh econ flight go. How long have

we got now on the cell? Last count had

18 minutes. Let me get an update. Okay.

Tell me what do we got to do to power up

to get some comm. Okay. We got a

procedure here that gets power first on

the limb. We figure we've got about 15

minutes worth of power left in the

command module. So we want you to start

uh getting over in the limb and getting

some power on that. This is Apollo

control at 57 hours 46 minutes ground

elapse

time. The black team of flight

controllers is now on station in mission

control center looking at possible

alternate missions as we have an

apparent serious oxygen leak in the

cryogenic oxygen in the service

module. And now in the process of

powering down the command module. Less

than 15 minutes remaining of uh

electrical power to the

CSM. Sometime later in the mission uh it

is expected that they would return to

the free return trajectory which they

left yesterday in the midcourse

correction burn number two.

returning to the uh alternate mission

now being considered at this point uh in

the trans lunar coast. It is

cheaper and swifter to coast on around

the moon and come back to Earth than it

is to do a deep space abort. Continuing

to monitor air ground from Apollo 13.

This is Apollo control. Both oxygen

tanks failing in the service module

meant the death of all three of its fuel

cells as well. With less than 15 minutes

of electricity remaining, the decision

is made to power up the lunar module.

The crew would tap into the oxygen tanks

and batteries inside of the lunar module

intended to keep a crew of two people

alive on the surface of the moon for 2

days. It now needed to keep a crew of

three alive for four. All three fuel

cells failing meant that the crew would

have significantly less water and

electricity than planned for the rest of

the mission. The crew would soon begin

to struggle with their short supply of

both of these resources as a result. And

uh Jack, have you all got good limb data

down there now? That's affirmative,

Fred. We're getting good LEM data. Okay,

everybody. Look, we got a number of long

range problems right now. We have the

burn to do, which is at about 79 hours,

28 hours from now. But right now, I want

the guys here in the room to concentrate

on keeping this thing right now going

along. All right. And watch it. This is

Apollo control. 58 hours 46 minutes

ground elapse time. Love and haze still

powering up the lunar module in

preparation for uh what turns out to be

an alternate mission in which no lunar

landing will be possible. In about 20

minutes in the Houston news center,

there will be a press conference in the

small briefing room. A press conference

is held in order to inform the media of

the developing situation. The explosion

had turned this mission from a

littleknown event into a major fiasco.

The media and public would begin to tune

in and find out about the precarious

situation the crew now find themselves

in. Participants in the forthcoming

press conference uh within the next 15

minutes or so will be uh man spacecraft

center deputy director Christopher Craft

Jr. Apollo spacecraft program office

manager James A.

McDivet and MSC Director of Flight

Operations Sigard

Schoberg. This will be in the small

briefing room in the Houston News

Center.

I guess I I really there are a lot of

things that could have happened. It

would be just pure conjecture. Anything

that's down there that's pressurized

could have let go and there are all

kinds of pressurized things or

pressurized hydrogen, nitrogen, oxygen

fuel cells. A it's a very complicated

bay that that this happened in. Can you

get them back? Taking in consideration

all the imponderables, the the power,

the oxygen, the landing area and all

this sort of thing. Is this if the

situation remains stable as it is at the

moment, there's no question. But what we

have the thing under control and we can

return the crew safely to the Earth.

Now, we're going to have to make some

compromises and procedures as how you do

that. If everything remains as is uh we

can get them back successfully. Now if

there was some change in the status of

the lunar module then that might that

might mean something else and we will

keep you appraised of that situation. Uh

Jim, I'm not clear on what the vetting

did to the uh spacecraft's attitude and

pitch roll in your

Well, he had a negative pitch and a

negative roll and uh that's one of the

clues that we had that something

happened in bay 4 in addition to the

fact that we had all these other

anomalies to the equipment that's in

there. It meant that it was pitching

nose down and it was rolling to the

left. I think the other thing you have

to remember is that uh we have certain

instrumentation that uh we can believe

or not believe. I mean by that that when

you have something like this happen you

don't know that you're not reading false

information from some of the

instruments. So you have to look at

those and see how they failed etc and

see what the measurements are see which

direction they went when they began to

fail to see whether that you're reading

true information.

All right, this one and then we're going

to come back. All right. Uh Chris, could

you uh put this in a a somewhat larger

perspective? Uh it seems obviously that

if this happened on the way back, the

the situation would be critical. I mean,

would be fatal. Indeed, it would. You

discuss this thing from the standpoint

of uh the resources you're left

with when it fails at this point in the

mission. Well, and anytime uh that you

still have the lunar module in the

condition that we have it in in this

case where we've not used any of its

consumables,

uh then we're in a very good situation.

We've always called the lamb a good

lifeboat under those circumstances. If

at any time in the mission, however, the

limb had separated and we had gotten

ourselves into a rendevous situation or

uh the the command module being around

the moon, then what you state is

absolutely true. It would it would be a

fatal situation.

Um, I know it's probably a little

premature, but um, seeing they have had

a a rough time, have you worked out um,

any schedules for um, a sleep period for

any of the astronauts?

I think this is a little premature for

that.

Forgive me if I put you on the spot, but

how would you classify this situation as

regards to these that we are familiar

with a little Well, I' I'd say this is

as serious uh situation as we we have

ever had in man space flight.

Did the fact that you went into a hybrid

trajectory yesterday pulling you out of

free free return, is that going to cause

you any troubles in trying to get back

around the moon?

No. As I said earlier, we're not on a

free return right now, but it it it

would only take a maneuver of about 20

to 40 feet per second to get you back on

a free return. And that could be done in

say 5 or 10 hours from now. We're going

to continue to schedule these briefings

throughout the mission whenever there's

a point where we think interpretation

would help and uh we'll be back again.

But I think we ought to get back to

mission control.

[Music]

personal

[Music]

com to back up and recap the earlier

maneuver pad or information regarding a

descent propulsion system abort for a

minimum return time.

This maneuver, should it be done, would

come at 79 hours 25 minutes 26 seconds

ground elapse time at an altitude above

the moon at 205 nautical miles.

The maneuver would be uh

1,797.7 ft per second. Pausing

rate, burn time of 8 minutes 35

seconds would produce entry interface at

about uh 133 hours ground elapse

time. Apollo 13 is now

185,455 nautical miles out from Earth.

Velocity showing on the display here in

mission

control

3,118 ft pers. We're continuing to stand

by at 59 hours 53 minutes ground elapse

time. This is Apollo control. Ground

control begins calculating a single burn

that will speed up the spacecraft's

return journey and put it onto a free

return trajectory. The burn is planned

for 2 hours past the closest approach to

the moon. Okay, Houston and Aquarius,

how do you read? Hello there, Aquarius.

Loud and clear. Uh, how do you read me?

There's an awful lot of background.

Okay, we got a lot of background uh

static. Jack, you're down in the mud.

You having a ground problems? Uh, you're

unreadable, Jack. Uh, we got a signal

meter right now. It keeps wavering up

and down. The best I'm getting is about

2.4 AGC. The crew begins experiencing

another unexpected challenge. The lunar

module's communication systems use the

same frequency as the third stage, which

had been ejected earlier in the mission.

The third stage had the same

communication system as the lunar module

so that ground control could measure its

position in space. It had been intended

that the lunar module wouldn't have been

powered up before the crew got to the

moon, giving the third stage time to

crash into the moon and avoiding any

interference. The unexpected change in

plans, however, had the crew power up

the lunar module onto the same frequency

that the third stage had already been

using. This gave the crew great

difficulty in hearing the ground

control, although it was not impossible.

Flighting go. Go ahead. They're having

trouble grabbing a hold of the S4B to

push it out of the way is what the

problem is. Okay. Well, we had comm

before. Can we get back to there? What

we're trying to do, and we're not having

any luck, there is one suggestion we can

do. We can turn the limb transceiver

completely off for about 2 to 3 minutes

and let them grab a hold of the S4B,

push it out of the way, and then bring

it back up.

Is that what we have to do now? We can't

talk to them to tell them to do that.

That's right. But if we can get up for a

lap in here, just say turn your

transceiver off for 3 minutes,

then turn it back on and go flight. Go

ahead. Is that our best step now to get

combat? That's our best step, right?

Capcom, give him that. We'll try. He's

not going to hear your flight right now.

Ground control came up with an

interesting solution to this problem.

The frequency that the lunar module and

third stage used was not fixed like a

standard radio station. Instead, the

communication systems read the incoming

frequency from the ground stations on

Earth and transmitted a matching

frequency at a ratio of 240 to

221. This is done because the spacecraft

is moving away from the ground stations

with enough velocity that the Doppler

effect of the spacecraft's radio

transmissions can be used to measure its

velocity and distance. The ground

stations transmit a known frequency, and

the return frequency will differ

depending on how fast the spacecraft is

traveling. Ground control can measure

how far off the return frequency is to

Earth's transmitted frequency and gather

this useful information. By matching the

frequency that the spacecraft sees from

ground control, they can double the

effective distance of the Doppler

effect, giving them a more accurate

reading of the spacecraft's velocity.

They will use this feature to send a

signal to the third stage, dragging its

frequency away from the lunar modules.

In order for the lunar module's

communication systems to not also be

altered by this frequency change, ground

control asked the crew to switch off

their communication system for 3

minutes. Ground control knew the crew

got their message when their

communications turned off moments later.

This gave ground control their

opportunity to drag the frequency of the

third stage away and then lock back onto

the lunar module. With the radio

frequencies now far enough apart to

avoid interference, the important

communication issue was resolved.

Flighting go.

Go ahead. It looks like you got it.

Calm, Jack. Okay, everybody, let's be

quiet. We have calm. Hello there,

Aquarius. We got a lot of business to

do. Hello, Houston. Aquarius, how do you

read? Hello there, Aquarius. Loud and

clear. Help me now. Okay, we're reading

you loud and clear, Jack. I hope it

stays this time. Ground control had been

calculating the resources they would

have on the return journey given their

single plan burn at 79 hours. The

numbers that come back do not look good.

Unless major changes are made, the crew

will run out of water in 31 hours. With

their planned trajectory, it will take

over 70 to return to Earth. The decision

is made to shut down the primary

guidance and navigation system, a

computer that uses water to cool itself.

By shutting down the guidance computer,

the spacecraft will lose its orientation

in space, but conserve that crucial

water. Because of this, ground control

wants the crew to get into a free return

trajectory. Now, while the guidance

computer is still powered up, they plan

to shut off the computer after they

enter a free return trajectory, and they

will do a secondary burn after they've

rounded the moon to speed up their

return home. This new trajectory plan

was not without its own challenges. The

descent propulsion system on the lunar

module was only designed to be fired one

time. Now, they were planning two burns,

carrying significantly more weight, and

in a configuration that the lunar module

had not been designed for. The crew

would also be without their primary

guidance and navigation system during

their second burn. Plans were considered

in which the crew would eject their now

dead service module to save weight and

speed up the return, but this would

involve exposing the command module's

heat shield to deep space for an

extended period of time. Something it

had not been designed to do. Okay, we'd

like to brief you on uh what our plan

is. Uh we're at this time water critical

in the limb, so we'd like to use as

little as possible. To do this, we're

going to plan to make a free return uh

maneuver of 16 ft per second at 61

hours, which is 37 minutes from now.

Then we're going to power down the

pings. At 79 hours, we'll go ahead and

uh make another abort maneuver to kick

what we got. But we'd like to get that

pings powered down as soon as possible.

Okay, the only item on page 10 is to

deploy the landing gear. Okay, we'll do

that now. control. You want that done,

right? Affirmative. Okay, stand by for

landing gear. Okay, let's watch the pyro

and the landing gear there, gentlemen.

Okay, power firing.

Hey, looks like landing gear depart from

here.

Roger, Aquarius, and your go for the

burn.

Okay, Corish, you're looking

good. All shut down.

And Aquarius, for your information, uh,

we now have 136 mile

perigee confirmed by Doppler. Okay, 136

mile perigee now. That's very nice. Oh,

wait a minute. Uh, Jack, did you say uh

Parisian or Parisian? Parisian.

Ah, that's better. The emergency plan to

use the lunar module's engine had

worked. They're now on a free return to

trajectory. The crew shuts off the

guidance and navigation computer that

had been consuming their limited supply

of water. Okay, Jim. And uh looks like

what we have to do is uh in order to

maintain uh even heating, we just have

to yaw the whole machine about 90° per

hour in

increments. So we'll give you a call

when it's time to yaw 90°. Ground

control came up with a compromise for

the passive thermal control. The lunar

module had no procedures to be able to

set up a passive thermal control role,

but they could still orient the

spacecraft using the reaction control

thrusters. The plan was to periodically

rotate the entire spacecraft and then

hold that new attitude until their next

thermal control maneuver where they

would rotate again. It wouldn't be as

smooth as a normal passive thermal

control roll, but manually rotating the

spacecraft every once in a while would

have the same effect. To recap briefly

the situation with Apollo 13, uh the

crew in the last hour was uh passed up a

paracinthian plus 2 hours maneuver,

which actually is primarily a speed up

maneuver to uh get them back to Earth

somewhat earlier than the normal free

return would bring them. Although a free

return trajectory had been successfully

established, the crew was not out of the

woods. They still had one more burn

planned for two hours past the closest

approach to the moon. Right now, they're

on a trajectory to land in the Indian

Ocean 76 hours from now. This posed

complications with recovery considering

the intended landing site was planned to

be the Pacific Ocean on the opposite

side of the planet. With water

consumption at an absolute minimum, the

crew was still projected to run out of

water 5 hours before landing. This burn

would speed up their return, landing 10

hours sooner. Landing sooner would help

their water supply issue and meant that

the Earth would be in a different point

in its rotation, placing the landing

point for Apollo 13 conveniently right

back in the Pacific Ocean. They would

spend most of their time preparing for

this burn. Extreme measures are taken in

order to conserve the lunar module's

limited resources. One of those measures

is to switch off the lunar module's

radio amplifier. This helps conserve

electricity at the cost of making their

communications with Earth far noisier.

Under usual circumstances, each crew

member would be drinking about 30 ounces

of water per day. They would need to

reduce their intake to just six, 1/5 of

their normal amount. The moon is tidily

locked with Earth, meaning only one side

will ever be shown to us. Today, the

crew of Apollo 13 will join an extremely

small group of people who have seen the

far side of the moon with their own

eyes. They will also be able to see the

moon surface in detail from just 164 mi

away. The crew prepares their film and

color cameras to capture this flyby. The

spacecraft is now well within the moon's

sphere of influence. The film

photographs the crew manages to capture

from the far side of the moon show its

craters in incredible detail. This is

only tempered by the fact they'd be

preparing to land there had the

explosion not happened yet.

Because of the unusual situation and

trajectory of this mission, Apollo 13

would set the record for the furthest

distance humans have ever been from

Earth.

249,25 mi, a record that still stands to

this day. Apollo control Houston, 77

hours 38 minutes into the flight, Apollo

13 uh has now rounded the corner, headed

back towards Earth. Uh we show a

velocity of a velocity of

7,62 ft/s and a distance from the moon

of

566 nautical

miles. We presently show Apollo 13 1,7

nautical miles away from the moon. Its

velocity slowing down now relative to

the moon now reading 6399 ft per second.

Apollo control Houston 77 hours 52

minutes now into the flight. We show 5

minutes away now from time of predicted

impact of the S4B. The third stage's

collision course with the moon ends with

an impact on the lunar surface traveling

2.58 km per

second. This leaves a 30 m wide crater

in the lunar

surface. The energy from this impact

rings the moon like a bell. A

seismometer placed 5 months earlier by

Apollo 12 picks up the seismic waves

from the impact 85 m away. This provides

data about both the moon's composition

and calibration of the seismometer. This

is one of the few scientific goals

Apollo 13 would be able to accomplish.

Oh yeah.

Yeah. We're no longer 135

miles. We're leaving.

It is now 2 hours past the closest

approach to the moon. The time for the

second lunar module burn had arrived.

The first burn lasted for 14 seconds.

This one will last for 4 and a half

minutes. Speeding up by a planned 861 ft

per second. Jim, you are go for the

burn. Go for the burn. Roger. Go for the

burn.

Less than 30 seconds away. The engine is

armed. Standing

by. Ground confirms ignition.

40%.

Houston

[Music]

copies. Attitude looks good at this

point. Brethren, Houston, you're looking

good.

Rider, one minute now into the

burn. Yips is looking good. 2 minutes

into the

burn. Fresh. You were looking good at 2

minutes. Still looking

good. Roger. Velocity building up. Uh,

disc shows we've gained 451 ft per

second at this time.

The on board display shows less than a

minute to go in the burn

now. Coming up on four minutes into the

burn.

Shut down. Roger. Shutdown.

That was Commander Jim Levelville

reporting shutdown. The engine is off.

We're at 79 hours 32 minutes into the

flight. I say that was a good burn. The

second burn was successful. The return

to Earth will now be 10 hours sooner.

and in a much better place for recovery.

Although the crew had enough oxygen to

breathe in, what they were breathing out

would start to be more of a concern. The

lunar module's smaller lithium hydroxide

canisters were designed to scrub the

carbon dioxide of two people. With

three, the levels of carbon dioxide

slowly rise within the spacecraft and

would reach dangerous levels if nothing

is changed. Ground control had been

aware of this issue since they had shut

down the larger CO2 scrubbers in the

command module, which were designed to

support three people. Fortunately, both

scrubbers worked in the same way. By

dragging carbon dioxide over lithium

hydroxide canisters, the chemicals would

react with the CO2, trapping it, letting

cleaner air pass through. This would

gradually scrub the CO2 from the

spacecraft's atmosphere, making it safe

to breathe. Unfortunately, the canisters

are different shapes. The command

module's canisters are large cubes,

while the canisters on the lunar module

are cylindrical and smaller. They are

not compatible with each other. Ground

control knew this would be an issue and

had been working on a solution to be

able to use the command module's larger

CO2 scrubber in place of the lunar

module's smaller one. They would need to

build an airtight adapter using only the

resources on board to fit a square peg

into a round hole. Okay, Houston, we

just got a mass alarm and ECS light. I

take it the partial pressure CO2 is

Yeah, that's what tripped it. Uh, chorus

Houston, say again. CO2. The CO2 inside

the spacecraft has reached a high enough

concentration to start setting off

alarms. The master alarm on the CO2

canister was expected to occur at some

point in the flight, the return flight.

There she goes.

This is Apollo control at 83 hours 11

minutes.

A change of shift press briefing is

being planned uh to begin in about 10

minutes at 12:35 a.m. in the main

auditorium at the Houston News Center.

The participants in the press conference

will be flight team flight director Jean

Cray and astronaut Tony England. Could

we have a rather detailed explanation of

the tests that were run in the

simulations with the lithium hydroxide

canisters and a description of

how this hose is being attached or will

be attached to a canister and

particularly what hose that is, where

does it come from and what's going

through it.

He brought you over one of our

canisters.

This is our

mailbox. As you know, we use the lithium

hydroxide to scrub CO2 out of the

spacecraft

atmosphere. Okay, I'll uh talk more

directly into it.

Uh we have a limited amount of lithium

hydroxide in the limb and uh it would

relieve a lot of the pressure on the

environmental control system if we could

use some of the canisters lithium

hydroxide canisters from the command

module. So we actually Jim Corelli over

in uh crew support division who designed

this thing and I it does an excellent

job.

What we do is we use the suit loop in

the limb and this is the scavenging

hose, the uh the exhaust hose if you

will from the suit and we just put the

lithium hydroxide canister on the end of

it. And it's not so easy to fasten on

there. Uh we've used a a data card out

of the flight

plan to make a structure so that the the

the plastic cover here won't collapse on

the end of the hose. The canister itself

is coated with Teflon and none of our

flight tape would stick to it. So, he

designed sort of a a a grid system that

goes around it uh that uh allows us to

fasten things to it. And we've had one

of these running for about 3 hours over

in the 11T chamber and crew systems. And

it uh all indications are that it's

doing the job.

I understand that we have about 16

cartridges in the command module and

each one will have a lifetime about 12

hours and we'll be running two at a

time, one on each of the suit loops in

the limb. Uh we were told before the

burn that uh uh two people would be in

the uh limb and one would be in the

command module. And later on I got a u

part of a quote which seems to indicate

that maybe that wasn't the case. His

quote was, "He's the only CMP that's

ever witnessed a dips burn sitting on

the ascent engine can," which would lead

one to believe that uh all three of them

were in the limb at the time of the

burn. Yeah, this is a uh interesting

item. Uh yeah, all three crew members

were in the LM at the time of the burn

and we had uh computed our dips gimbal

trim position for the uh uh man in the

command and service module spacecraft

which caused a center of gravity

uh movement that caused the engine

gimbals to compensate for the fact he

was in there. So, we saw that excursion

and then once we found out that uh yeah,

we had a CMP in the uh LEM spacecraft,

we knew why the excursion.

Okay, let's take ArchN. Oh, yeah.

Followed up with one car. Would you care

to speculate uh why all three of them

got together in the limb at that time?

I think the third man wanted to see what

was going

on. From the sounds of all the

uh work that has gone on and is still

going on, this flight's uh probably a

lot bigger test of the uh system on the

ground than up here. Yeah, you've been

uh you've been working it out a little

bit. Well, everybody down here is 100%

optimistic. Uh looks like we're on the

upside of the whole thing. No, ground

control passes up a procedure that will

allow the crew to use the lunar module

to set up a proper passive thermal

control roll rather than relying on the

manual 90° turn. How'd you like to spend

a week on an aircraft carrier getting

back? If I can uh get on an aircraft

carrier and I'm sure how long it takes

today. Ground control must verbally

guide the crew through building the

adapter to fit the command module CO2

scrubber into the lunar module's air

intake. Okay. Uh, I think the equipment

you'll need will

be two command module lithium hydroxide

canisters. The crew constructs two

adapters using ground controls verbal

guidance. This improvised solution would

be known as the mailbox from its shape.

The crew no longer had to rely on the

lunar module's limited CO2 scrubbing

capabilities and now had access to more

than enough lithium hydroxide canisters

to last them the rest of the journey.

Okay. When I was upstairs just a minute

ago, I uh I noticed appear what appeared

to be some new binning from down the

service module way. Uh I noticed it out

window one and also saw one chunk of uh

metal, loose metal about uh 4 in square

that was tumbling around uh silver in

color. It looked like it had come from

somewhere down in the service module.

I'm looking out the limb window now and

I see a good part of the new starfield

that's created

first and about a thousand little

sparkls out here. Fred Hayes looks out

of the windows and notices something

venting coming from the same area as the

initial accident. Think of any

normal phenomena that might occur like

maybe a hydrogen tank that's over

pressurized.

Yeah, we thought of that, Jim. We heated

up that tank and we haven't been using

any hydrogen and therefore it couldn't

be venting any overboard relief. It's

believed that with the side panel of the

service module blown off, the nearly

full hydrogen tanks would be directly

exposed to the sun for long enough that

they would start to pressurize and vent

through a relief valve. Given the

electrically dead service module, the

sensors and telemetry that would help

diagnose an event like this would also

be dead. The crew and ground control are

completely blind to the true state of

the command service module and would

have very little information to find out

what's venting.

may attack. But I think our PC

is

[Applause]

officially higher. Okay. Understand PTC.

Earth is coming by lower and moon is

coming by higher. Whatever seemed to be

venting would start to throw off their

passive thermal control role, slowly

adding its own wobble and procession.

Okay. Uh we're considering a midcourse

correction at 104 hours. Uh about 20

hours from now, 18 hours from now.

Ground control notices the trajectory

they're on would have them re-enter

Earth at a slightly shallow angle. They

plan another midcourse correction burn

to bring their re-entry angle back to

levels they're comfortable with. Uh

we're looking at the sheet tank pressure

rising. Uh we expect it to uh to blow.

Uh we don't know exactly what time it'll

go. Somewhere around 105 hours or

perhaps later than that. Uh we we've got

plenty of blowown capability and we we

just uh thought you ought to be

informed. The lunar module's engine

works by using helium to force fuel from

its tanks into its engine. This helium

was supplied from a super critical

helium tank inside of the lunar module.

As the tank would be warmed by sunlight

inside of the spacecraft, the pressure

would slowly rise during the mission. To

fix that, the tank was purposefully

underfilled on the ground so that as the

temperature rose inside the tank during

the mission, the helium would be at the

correct pressure to use the engine when

they got to the moon. Under usual

circumstances, the lunar module would

land on the moon and vent this helium,

stopping any possibility of an over

pressure. Apollo 13's unplanned

excursion meant that the lunar module's

helium tanks would be consistently

rising in temperature and pressure until

a burst disc breaks. Fortunately, the

lunar module's engine can still be used

even after this helium burst disc

breaks. Since the crew had already fired

the lunar module's engine, helium would

be trapped within the engine's fuel

tanks that could be used to start it up

again for a limited time. This feature

is called blowdown. With the dead

command service module, the lives of the

crew are entirely reliant on the lunar

module and its batteries. They need all

of its systems to work and are in no

position to deal with more unexpected

challenges. The crew would not be so

lucky.

Okay, man. Uh, I just heard a little

pump sounded like down in the descent

stage and

uh saw a new uh shower snowflakes go up

that looked like they were a minute down

that way. We don't see anything wrong.

For example, your sheet tank appears to

be okay as far as we can see. Whatever

blew in the lunar module's descent stage

was not the helium tank. It would be a

few hours earlier than expected and the

telemetry they could see told them the

tank was still pressurized. The lunar

module's descent stage contains four

large batteries which power the

spacecraft. It is believed that battery

2's electrolyte leaked inside of the

battery, creating a short circuit with

itself in the magnesium battery casing.

This short circuit through the

electrolyte released oxygen and hydrogen

gas from the electrolyte which

accumulated around the battery and then

ignited. This created a large enough

explosion for the crew to hear it, but

it wasn't destructive enough to knock

battery 2 off the line. The snowflakes

Fred Hayes were seeing were parts of his

own spacecraft mixed with leaked battery

electrolyte.

And Houston looks like service module

via at least momentarily. How about the

descent stage? Does uh Fred reported

venting down there? Uh do you still see

that? No. Fred hasn't seen anything else

in the descent stage. Fortunately, the

batteries would continue to function and

the short circuit didn't seem to have

any serious effects on them. How does it

feel, Jack?

I tell you, Dee, it's cold up in

there. I don't know whether we'll be

able to sleep up there tonight. It must

be about 35 or 40°.

Ro, that's what I was worried about. The

emergency situation the spacecraft is in

does not provide the crew with much

comfort. Usually, part of the

electricity the spacecraft would be

using would warm up the spacecraft and

make it comfortable to be in. With

electricity usage at an absolute

minimum, the spacecraft would plummet to

temperatures as low as 40° Fahrenheit or

4 C. Many of the water-based foods like

hot dogs have frozen solid. Water

droplets from the astronaut's breath

condense onto every surface, including

the ones behind the control panels and

in its wiring. The third midcourse

correction burn is here. This one is a

short burn that will help trim their

re-entry angle into better margins.

College

Ignition. Thrust looks good.

Shut down. 470.

Got some other information. Uh we should

have some good dope on your trajectory

in about 2 hours. Looked like to us that

the burn was real good, however, and uh

we're taking a close look at it and

we'll get back with you on that in about

2 hours. Now, another thing that we're

expecting to have happen uh is that uh

the sheet tank is going to reach its

burst limit. And this is uh supposed to

be a non-propulsive event, but you might

hear it and you might see something. We

are still watching the superc critical

helium pressure aboard the LM descent

stage increase gradually. The pressure

is now reading

1,937 lbs per square

in. And uh we see the pressure dropping

at this time. The control officer

reports that the burst disc has

ruptured. We just uh as we were making

this announcement. Anything?

[Applause]

Yeah, Jack, I just about ready to call

you. Underneath quad

four. I noticed a lot of

uh sparkly coming out.

Did you hear or feel anything?

I sure can. But, uh, I think it changed

our, uh, it changed our our, uh,

PTC. I think we're probably going to

have to reestablish

PTC. Yeah, I was in a right jaw and now

I'm in a left

[Applause]

jaw at a much faster rate

than the burst disc finally gives and

vents the super critical helium tank

into space. This event pushes the

spacecraft with enough force that not

only does it stop the passive thermal

control roll, but then reverses it at a

much faster rate than they were

originally spinning. Roger. Uh, have you

effectively established PTC in the

opposite direction then? Well, you can

say that. I I'm not too sure just what

kind of picture roll I got coming up

with for y'all. Is that what they call a

nonpropul?

Right. I'd hate to see a propulsive one.

Give me both. Meanwhile, back to the

drawing board for a non-reul.

The uh super critical helium burst disc

ruptured at about 108 hours 54 minutes

40 seconds after reaching a pressure of

1937 lb per square in. The uh pressure

of the escaping gas, which was thought

ahead of time to be a was predicted to

be a non-propulsive vent, turned out to

be uh very much a propulsive vent. Uh

this rotational rate was stopped by the

vent and uh started up again in the

opposite

direction and it is now rotating about

one

revolution every uh 2 minutes. One

revolution a little less than every 2

minutes as compared with a revolution

every 18 or 19 minutes in the opposite

direction prior to the vent. How's the

temperature up there, Jack? You guys

chopping wood to keep warm?

Uh Jee, it's about uh 51, I think, or 50

in the uh lamb, and it's about uh I

don't know, 45 or or a little bit less

in the command module. Do you believe

it's cold up there? Yes, we we used to

call the command module the bedroom, and

it's now the refrigerator. The near

freezing temperatures inside of the

spacecraft, combined with one crew

member on watch out at all times, would

make it near impossible to get any

meaningful amount of rest. By this

point, three full days after the

explosion, all crew members are

exhausted and dehydrated. The rationing

of water that the crew had been

undergoing had its own ill effects as

well. By the end of the mission, Fred

Hayes would lose 6 lb of body weight.

Jack Swagger would lose 11 lb and Jim

Lovel would lose 14. Fred Hayes would

discover he developed a urinary tract

infection that would later become a

kidney infection. He would start feeling

the chills in an already frozen

spacecraft. A small burn with the

reaction control thrusters is planned to

bring the spacecraft into the best

re-entry angle they could try to get.

Less than 2 minutes away now from

scheduled time of ignition.

Okay, it looks like we had a minus2 bias

47. We're burning. Copy that, Fred. Fred

Hayes reporting that the burn is

underway. We're at 137 hours 40 minutes

into the

flight. Wave shut down. Re-entry is fast

approaching. The service module will be

jettisoned before the lunar module, a

first in the Apollo missions. Ejecting

the service module will expose its true

damage to the crew for the first time.

The crew is prepared to capture this

event on their cameras.

Copy that.

We copied that report uh from Jim

Levelville of service module separation

at 138 hours. Uh 2 minutes 8 seconds.

You're being Jack.

And there's one whole side of that

spacecraft missing.

Is that right?

Right by the uh look out there.

Right by the high gate antenna. The

whole panel is blown out almost from the

uh base to the engine.

Copy that.

Yeah, it looks like it got to the SPS

bell, too.

You can ding the SPS engine bell, huh?

Way look that's just dark brown streak.

It's really a mess.

Was the belt deformed on the outside or

just uh nicked or what?

I think the explosion from what I can

see, Joe, had uh had fainted. I don't

know whether it did any actual

transformation or not.

Okay, man. That's unbelievable.

[Music]

Yeah, and Joe, looks like a lot of uh a

lot of debris is just hanging out to the

side uh near the SP antenna.

Roger, Jim. The crew spends the next 3

hours preparing to jettison their lunar

module. They will do so 1 hour before

re-entry. And uh you are go for fire

alarm.

The damaged service module and their

lunar module would burn up in Earth's

atmosphere.

Okay, copy that.

Farewell Aquarius and we thank you. This

is Apollo Control Houston at 141 hours

31 minutes into the flight. We've had

lunar module jettison. You're looking

good. We're real happy with the

trajectory. And a minute ago, we just

lost contact with your friend Aquarius.

Okay. Where did she go? Oh, I know.

She's up there somewhere. She sure was

good. Hey, just as I said that, we got

another burst of lamb data, so I guess

it's still ticking. Less than 7 minutes

now from time of entry into the Earth's

atmosphere. Okay, we just had one last

uh time around the room and everybody

says you're looking great. Thank you.

Okay, los in uh a minute or a minute and

a half. Uh at entry attitude, we like on

me, Charlie, and welcome home. Thank

you. During re-entry, the spacecraft

hits the atmosphere with enough velocity

that it turns the surrounding air into

plasma, which blocks any radio signals.

This is a known event that will cause

Apollo 13 to lose communications during

their most intense phase of re-entry.

This is known as loss of signal or loss.

Apollo Control Houston. We've just had

loss of signal from

Honeysuckle with Apollo 13. Our last

velocity reading was

35,837 ft per second with a range to go

of

1791 nautical

miles. The period of blackout for the

spacecraft uh should have begun about 20

some odd seconds ago. We have about 1

minute to go now from time of end to

blackout. Less than 10 seconds now. We

will attempt to contact Apollo 13

through one of the Oria

aircraft. Continuing to monitor this

Apollo control Houston. We've had a

report that Aria 4 aircraft has

acquisition of signal.

Odyssey Houston. We show you on the

mains. It really looks great. An

extremely loud applause as Apollo 13 on

main shoots comes through loud and clear

on the television display here. The

three exhausted astronauts land in the

Pacific Ocean and get picked up by the

helicopter carrier USS Eoima. They will

be going home safe. The emergency

measures taken to save the crew of

Apollo 13 after the accident were a

success. The moon landing on the Fromaro

crater, however, remained out of reach.

With the spectacle of the rescue now

concluded, focus shifted entirely to one

lingering question. Why did this happen?

A review board is assembled in order to

investigate the origin of the explosion.

Looking back at the telemetry, oxygen

tank 2 was showing some very strange

readings right before the explosion. 1

and 1/2 minutes before the accident, the

pressure within oxygen tank 2

unexpectedly rose extremely high. The

pressure maxed out at 1,08 PSI, at which

point a relief valve opened, which

lowered the pressure to 996 psi before

the telemetry suddenly dropped out from

the explosion. This unexpected pressure

rise could not be accounted for by any

of the energy entering the tank from its

heaters, fans, or sensors. The crew was

not made aware of the sudden pressure

rise because of previous issues around

the hydrogen tank. The hydrogen tank's

low pressure warning light happened to

be activated before the oxygen tank's

high pressure warning light. Both were

part of the same cryogenic warning light

subsystem. Since the system could not

display both of these errors

simultaneously, the hydrogen tank's

mundane low pressure reading had

overwritten the immediately

life-threatening oxygen tank

high-pressure warning. The temperature

probe inside of that tank also showed a

rapid and unexpected rise in its

temperature a mere 20 seconds before the

explosion. In addition to the

temperature and pressurizing before the

explosion, the energy usage indicated

electrical arcing was happening

somewhere inside of that tank. About 2.7

seconds after the cryopans were turned

on, an unexpected 11.1 amp spike and a

matching voltage drop were recorded on

the telemetry for that tank's electrical

system. Materials used inside of the

oxygen tank, like the Teflon insulation

for the wiring, are not flammable under

normal conditions. In an environment of

pure superc critical oxygen, however,

teflon would be able to propagate a

flame. The board looks into the specific

oxygen tank's history, which reveals

some alarming details. This tank was

intended to be flown on Apollo 10 and

had completed its acceptance testing

beforehand. It showed no issues then.

Due to previous Apollo flights showing

some issues with electromagnetic

interference around the vacuum pumps on

the cryogenic tanks, the decision was

made to remove and modify the shelf

containing the oxygen tanks. In order to

remove the shelf for modification, the

11 screws that hold the shelf onto the

service module had to be taken out. One

was forgotten. The ground crew, having

believed all screws were removed and

that the shelf was separated from the

service module, attempted to remove it.

The remaining crew pivoted the entire

assembly upwards, hitting the shelf

above it before dropping 2 in back down

into place. At this point, the ground

crew had noticed their mistake, reported

this incident, and properly removed the

shelf. Testing would have to be done in

order to verify that this tank drop

didn't damage them. With the soon

upcoming launch of Apollo 10 and the

time it would take to test, it was

decided that a new tank would be brought

in and used instead of the dropped one.

This decision spared Apollo 10 from this

oxygen tank. The tank would later be

tested and would verify that all of its

components worked. It passed these tests

and was installed inside of the service

module slated for Apollo 13. The service

module was moved to Kennedy Space Center

where the rest of the Saturn 5 was being

put together. The Saturn 5 was assembled

and then moved onto the launchpad in

order to complete the countdown

demonstration test. This was a rehearsal

of activating and pressurizing all of

the rocket systems up until launch. This

would verify that everything worked

correctly when it came time to actually

launch. The oxygen tanks inside of the

service module were part of this test.

They would be pressurized, tested, and

then depressurized. Both tanks

pressurized and worked normally. During

depressurization, however, oxygen tank 2

would not drain all of the way. It was

stuck at 65% and could not be made to

drain more than that. Normal

depressurization procedures involved

blowing gaseous oxygen through the vent

line, which would push on the oxygen and

force it up through a tube in the center

of the tank, which would then drain

through the fill line. It was known that

manufacturing tolerances around one

section of this fill tube, called the

dog's leg, were not particularly tight.

With manufacturing tolerances stacked

up, a particularly loose fill tube could

be jolted open from something like the

tank drop. This is believed to be the

main cause of failure to drain

completely. The gaseous oxygen intended

to push the denser oxygen up through the

fill tube was simply leaking back

through the jolted open fill tube,

leaving the rest of the oxygen in the

tank. The technicians on the ground were

aware of this issue and were not

concerned by it. The failure to drain

completely was not considered a problem

for flight as the spacecraft systems

would be supplied by a separate tube

which works fine. It was decided that

they would power the heaters inside of

that tank in order to boil off the

oxygen and drain it that way. The

technicians used the 65V ground power

supply to power the heater inside of

oxygen tank 2. Unbeknownst to the ground

crew, a crucial piece of information was

not passed up the line to the company

responsible for manufacturing the tank.

Originally, the ground power systems

used 28vt power and so the tank's

temperature limit switch was only rated

for 28 volt. The ground power supply

system was later upgraded to 65 volts.

The heaters rely on a thermal limit

switch in order to separate the circuit

if it gets too hot. With the upgraded

ground power, testing showed that the 65

volts flowing through the thermal limit

switch rated for less than half that

welded the switch shut, rendering it

useless. The heaters on that tank from

that moment onwards had absolutely no

thermal limits it could reach before

shutting off. Ground control was

watching the temperature sensor inside

of that tank to make sure it didn't

reach temperatures too high. But since

that sensor was not designed to display

temperatures higher than 84 degrees

Fahrenheit, they would not be aware that

the heaters were being operated well

beyond their safe temperatures. To

ground control, the tank was only 84°

and anything beyond that would be

stopped by the temperature limit switch

opening. Both assumptions were wrong.

The heaters, now unbound by the disabled

temperature limit switch, would reach an

estimated 1,000° F, hot enough to make

steel visibly glow red. The tank would

sit like this, cooking its own internals

for the next 8 hours. The extreme heat

inside of the tank damaged the Teflon

insulation for the cryofan wires,

exposing bare metal. Now, this meant

that anytime the cryofans were

activated, it risked creating a short

within the oxygen tank. Ground control,

unaware of the dangerous situation the

tank is now in, and wanting to make sure

that tank wouldn't act up during launch

procedures, decided to test the tank

again. The tank didn't show any other

issues during testing and so it was

decided that it would be good to launch.

The tank would also fail to drain

completely on this occasion, prompting

the ground crew to repeat the heating.

The same mistake had been made twice.

This tank would undergo another round of

extreme overheating, which continued to

burn off the insulation around the wires

for the cryopans. With the now severely

damaged Teflon insulation around the

cryofan wires and a ground crew

oblivious to the severe damage inside of

that tank, it was certified as good to

go and then launched into space. This

set the stage for the explosion. When

the astronauts were up in space, the

cryopans were activated and an

electrical arc was formed across the

wires. The teflon insulation, severely

degraded and sitting in a pure superc

critical oxygen environment, ignited

from the electrical spark like the fuse

to a bomb. This teflon insulation burned

for a minute and a half. The fire

created extra pressure inside of the

superc critical tank which began

venting. It reached the temperature

sensor and then the point where the

wires entered the superc critical oxygen

tank. This also happened to be the

weakest point in the tank where the

wires passed through into the

pressurized environment. This is the

part of the tank that gave out and

triggered the

explosion. It was incredibly lucky for

the crew that the tank exploded when it

did. If it were sooner, it would have

left the crew stranded with the same

resources, but a far longer journey

ahead of them. If it had happened later

and the crew had entered lunar orbit

like they were planned to, it would have

also been fatal. The service propulsion

system was not made to send the entire

Apollo stack back to Earth. If they had

separated, Jack Swiger would have been

the only one aboard the command service

module in lunar orbit. With the moon

blocking radio communications for one

half of that orbit, he would have

possibly had to deal with all of the

consequences of the tank's explosion

completely and entirely alone. Even if

the crew on the lunar surface managed to

hear about this and abort their moon

mission, there still would have been no

way to save the

astronauts. The descent stage containing

the oxygen they now needed to get home

would have been left on the surface of

the moon.

The wires had not ignited the first two

times the cryofans were stirred. It was

on the third stir that the wires floated

close enough together to arc. The rate

that they were stirring these fans was

changed from their original plans.

Because of that tank's quantity gauge

failing offscale high, ground control

wanted these cryotanks to be stirred at

a much higher rate. because of the uh O2

tank 2 quantity sensor dropout. Uh uh

ECOM wants to keep a little closer track

of the uh of the cryo quantities and

he's going to be asking you to stir all

the cryo tanks at slightly more frequent

intervals than um than have been

planned. And the first time is now. This

decision placed the third stir of the

oxygen tank within the only survivable

section of this mission where this

incident could happen. If this gauge

worked as intended, the cryos would have

been stirred at their normal rates,

placing the third stir of that cryopan

in lunar orbit with no way to return

home. During the explosion, the

telemetry indicated that the reactant

valves were just the oxygen on fuel

cells one and three were jolted closed.

The crew was not made aware of this

issue because the system on the service

module only reported if both the

hydrogen and oxygen reactant valves

closed. The hydrogen reactant valve

remained open and so the system showed

that they should still work. If the crew

had been made aware of this issue, they

could have opened those reactant valves

and sent oxygen from the still working

tank into those fuel cells to keep them

running. Because of this oversight, the

service module was stuck with a far

lower power output immediately following

the explosion. It also left mission

control in a position where they needed

to reroute their limited power onto the

dead AC bus 2 in order to start up

sensors just so they could figure out

what was going on. These findings along

with many others were used to issue

changes to procedure and upgrades to the

Saturn 5 rocket planned for future moon

landings. The oxygen tank would be

completely redesigned, removing the

teflon insulation and replacing it with

magnesium oxide, as well as sheathing

all of the wires together in stainless

steel. Now that NASA had more knowledge

about how superc critical oxygen moves

in a zeroravity environment, it was

decided that the cryopans could be

removed altogether. The quantity gauge

was redesigned. An emergency battery and

oxygen tank were added to the service

module. The warning alarm system was

redesigned and procedures for the lunar

module's lifeboat mode were dramatically

improved along with many other upgrades.

With the cause of the explosion tracked

down, the board closes their

investigation with this statement made

to the House of Representatives. The

Apollo 13 accident, which aborted man's

third mission to explore the surface of

the moon, is a harsh reminder of the

immense difficulty of this undertaking.

The total Apollo system of ground

complexes, launch vehicle, and

spacecraft constitutes the most

ambitious and demanding engineering

development ever undertaken by man. For

these missions to succeed, both men and

equipment must perform to near

perfection. That this system has already

resulted in two successful lunar surface

explorations is a tribute to those men

and women who conceived, designed,

built, and flew it. Perfection is not

only difficult to achieve, but difficult

to maintain. The imperfection in Apollo

13 constituted a near disaster, averted

only by outstanding performance on the

part of the crew and the ground control

team which supported them. The board

feels that the Apollo 13 accident holds

important lessons which when applied to

future missions will contribute to the

safety and effectiveness of man space

flight. Mr. Chairman, this concludes my

prepared statement.

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