- Pad 39-A (7)
- Saturn-V AS-508 ()
- High Bay 1
- MLP 3
- Firing Room 1
- James A. Lovell, Jr.
- John L. Swigert, Jr.
- Fred W. Haise, Jr.
- 06/13/69 - S-IVB ondock at KSC
- 06/29/69 - S-II Stage ondock at KSC
- 06/16/69 - S-1C Stage ondock at KSC
- 07/07/69 - S-IU ondock at KSC
- 04/11/70 - Launch
- Odyssey (CM-109) and Aquarius (LM-7)
- Apollo 13 was supposed to land
in the Fra Mauro area. An
explosion on board forced Apollo 13
to circle the moon without
landing. The Fra Mauro site was reassigned to
- Saturday, April 11, 1970 at 13:13 CST.
- At five and a half minutes after liftoff, Swigert, Haise,
and Lovell felt a little vibration. Then the center engine of the S-II
stage shut down two minutes early. This caused the remaining four
engines to burn 34 seconds longer than planned, and the S-IVB
third stage had to burn nine seconds longer to put
Apollo 13 in orbit.
- Days before the mission, backup LM pilot Charlie Duke inadvertently
exposed the crew to German measles. Command module pilot, Ken Mattingly,
turned out to have no immunity to measles and was replaced by backup
command module pilot Jack Swigert.
- Ground tests before launch, indicated the possibility of a poorly
insulated supercritical helium tank in the LM's descent stage so the
flight plan was modified to enter the LM three hours early in order
to obtain an onboard readout of helium tank pressure.
- The No. 2 oxygen tank, serial number 10024X-TA0009 had been
previously installed in the service module of
Apollo 10, but was
removed for modification (and was damaged in the process of
removal). The tank was fixed, tested at the factory, installed in the
Apollo 13 service module. and tested again during the Countdown
Demonstration Test (CDT) at the Kennedy Space Center.beginning March
16, 1970. The tanks normally are emptied to about half full, and No. 1
behaved all right. But No. 2 dropped to only 92 percent of
capacity. Gaseous oxygen at 80 psi was applied through the vent line
to expel the liquid oxygen, but to no avail. An interim discrepancy
report was written, and on March 27, two weeks before launch,
detanking operations were resumed. No. 1 again emptied normally, but
No. 2 did not. After a conference with contractor and NASA
personnel, the test director decided to "boil off" the remaining
oxygen in No. 2 by using the electrical heater within the tank. The
technique worked, but it took eight hours of 65-volt DC power from the
ground-support equipment to dissipate the oxygen. Due to an oversight
in replacing an underrated component during a design modification, this
turned out to severely damage the internal heating elements of the tank.
- Altitude: xxx miles
- Inclination: xxx degrees
- Duration: 05 Days, 22 hours, 54 min, seconds
- Distance: miles
- Lunar Location: None
- Lunar Coords: None
- April 17, 1970
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- Third lunar landing attempt. Mission was aborted after rupture of
service module oxygen tank. Classed as "successful failure" because of
experience in rescuing crew. Spent upper stage successfully impacted
on the Moon.
- The first two days the crew ran into a couple of minor surprises,
but generally Apollo 13 was looking like
the smoothest flight of
the program. At 46 hours 43 minutes Joe Kerwin, the CapCom on
duty, said, "The spacecraft is in real good shape as far as we
are concerned. We're bored to tears down here." It was the last
time anyone would mention boredom for a long time.
- At 55 hours 46 minutes, as the crew finished a 49-minute TV
broadcast showing how comfortably they lived and worked in
weightlessness, Lovell stated: "This is the crew of
wishing everybody there a nice evening, and we're just about ready
to close out our inspection of Aquarius (the LM) and get back
for a pleasant evening in Odyssey (the CM). Good night."
- Nine minutes later, Oxygen tank No. 2 blew up, causing No. 1
tank also to fail. The Apollo 13 command
modules normal supply
of electricity, light, and water was lost, and they were about
200,000 miles from Earth.
- The message came in the form of a sharp bang and vibration.
Jack Swigert saw a warning light that accompanied the bang, and
said, "Houston, we've had a problem here." Lovell came on and told the
ground that it was a main B bus undervolt. The time was 2108
hours on April 13.
- Next, the warning lights indicated the loss of two of
three fuel cells, which were the spacecrafts prime source of
electricity. With warning lights blinking on, One Oxygen tank
appeared to be completely empty, and there were indications that
the oxygen in the second tank was rapidly being depleted.
- Thirteen minutes after the explosion, Lovell happened to look out
of the left-hand window, and saw the final evidence pointing
toward potential catastrophe. "We are venting something out into
the- into space," he reported to Houston. Jack Lousma, the CapCom
replied, "Roger, we copy you venting." Lovell said, "It's a gas of
some sort." It was oxygen gas escaping at a high rate from the
second, and last, oxygen tank.
- (by James A. Lovell, from Apollo Expeditions to the
- by Edgar M. Cortright, NASA SP; 350, Washington, DC, 1975 )
- The first thing the crew did, even before discovering the oxygen
leak, was to try to close the hatch between the CM and the LM. They
reacted spontaneously, like submarine crews, closing the hatches
to limit the amount of flooding. First Jack and then Lovell tried to
lock the reluctant hatch, but the stubborn lid wouldn't stay
shut. Exasperated, and realizing that there wasn't a cabin leak,
they strapped the hatch to the CM couch.
- The pressure in the No. 1 oxygen tank continued to drift
downward; passing 300 psi, now heading toward 200 psi. Months
later, after the accident investigation was complete, it was
determined that, when No. 2 tank blew up, it either ruptured a
line on the No. 1 tank, or caused one of the valves to leak. When
the pressure reached 200 psi, the crew and ground controllers
knew that they would lose all oxygen, which meant that the
last fuel cell would also die.
- At 1 hour and 29 seconds after the bang, Jack Lousma, then
CapCom, said after instructions from Flight Director Glynn
Lunney: "It is slowly going to zero, and we are starting to think
about the LM lifeboat." Swigert replied, "That's what we have
been thinking about too."
- Ground controllers in Houston faced a formidable task. Completely
new procedures had to be written and tested in the simulator before
being passed up to the crew. The navigation problem had to be solved;
essentially how, when, and in what attitude to burn the LM descent
engine to provide a quick return home.
- With only 15 minutes of power left in the CM, CapCom told the
crew to make their way into the LM. Fred and Jim Lovell quickly
floated through the tunnel, leaving Jack to perform the last chores in
the Command Module. The first concern was to determine if there were
enough consumables to get home? The LM was built for only a 45-hour
lifetime, and it needed to be stretch to 90. Oxygen wasn't a
problem. The full LM descent tank alone would suffice, and in
addition, there were two ascent-engine oxygen tanks, and two backpacks
whose oxygen supply would never be used on the lunar surface. Two
emergency bottles on top of those packs had six or seven pounds each
in them. (At LM jettison, just before reentry, 28.5 pounds of oxygen
remained, more than half of what was available after the explosion).
- Power was also a concern. There were 2181 ampere hours in the LM
batteries, Ground controllers carefully worked out a procedure where
the CM batteries were charged with LM power. All non-critical systems
were turned off and energy consumption was reduced to a fifth of normal,
which resulted in having 20 percent of our LM electrical power left when
Aquarius was jettisoned. There was one electrical close call during
the mission. One of the CM batteries vented with such force that it
momentarily dropped off the line. Had the battery failed, there would
be insufficient power to return the ship to Earth.
- Water was the main consumable concern. It was estimated that the
crew would run out of water about five hours before
which was calculated at around 151 hours. However, data from Apollo
11 (which had not sent its LM ascent stage crashing into the
in subsequent missions) showed that its mechanisms could survive seven
or eight hours in space without water cooling. The crew conserved
water. They cut down to six ounces each per day, a fifth of normal
intake, and used fruit juices; they ate hot dogs and other wet-pack
foods when they ate at all. The crew became dehydrated throughout
the flight and set a record that stood up throughout Apollo: Lovell
lost fourteen pounds, and the crew lost a total of 31.5 pounds,
nearly 50 percent more than any other crew. Those stringent measures
resulted in the crew finishing with 28.2 pounds of water, about 9 percent
of the total.
- Removal of Carbon Dioxide was also a concern. There were enough
lithium hydroxide canisters, which remove carbon dioxide from the
spacecraft, but the square canisters from the Command Module were not
compatible with the round openings in the Lunar Module environmental
system. There were four cartridge from the LM, and four from the
backpacks, counting backups. However, the LM was designed to support
two men for two days and was being asked to care for three men nearly
four days. After a day and a half in the LM a warning light showed
that the carbon dioxide had built up to a dangerous level. Mission
Control devised a way to attach the CM canisters to the LM system by
using plastic bags, cardboard, and tape- all materials carried on
- One of the big questions was, "How to get back safely to Earth?"
The LM navigation system wasn't designed to help us in this
situation. Before the explosion, at 30 hours and 40 minutes,
had made the normal midcourse correction, which would take it out of a
free-return-to-Earth trajectory and put it on a lunar landing
course. Now the task was to get back on a free-return course. The
ground computed a 35-second burn and fired it 5 hours after the
explosion. As they approached the
Moon, another burn was computed;
this time a long 5-minute burn to speed up the return home. It took
place 2 hours after rounding the far side of the
- The Command Module navigational platform alignment was transferred
to the LM but verifying alignment was difficult. Ordinarily the
alignment procedure uses an onboard sextant device, called the
Alignment Optical Telescope, to find a suitable navigation star. Then
with the help of the onboard computer verify the guidance platform's
alignment. However, due to the explosion, a swarm of debris from the
ruptured service module made it impossible to sight real stars. An
alternate procedure was developed to use the sun as an alignment star.
Lovell rotated the spacecraft to the attitude Houston had requested
and when he looked through the AOT, the Sun was just where it was
expected. The alignment with the Sun proved to be less than a half a
degree off. The ground and crew then knew they could do the 5-minute
P.C. + 2 burn with assurance, and that would cut the total time of
our voyage to about 142 hours. At 73:46 hours the air-to-ground
transcript describes the event:
- Lovell: O.K. We got it. I think we got it. What diameter
- was it?
- Haise: Yes. It's coming back in. Just a second.
- Lovell: Yes, yaw's coming back in. Just about it.
- Haise: Yaw is in....
- Lovell: What have you got?
- Haise: Upper right corner of the Sun....
- Lovell: We've got it!
- If we raised our voices, I submit it was justified.
- "I'm told the cheer of the year went up in Mission Control.
Flight Director Gerald Griffin, a man not easily shaken, recalls:
"Some years later I went back to the log and looked up that
mission. My writing was almost illegible I was so nervous. And
I remember the exhilaration running through me: My God, that's kind of
the last hurdle -- if we can do that, I know we can make it. It was
funny, because only the people involved knew how important it was to
have that platform properly aligned." Yet Gerry Griffin barely
mentioned the alignment in his change-of-shift briefing -- "That
check turned out real well" is all he said an hour after his
penmanship failed him.
- James A. Lovell ( Apollo Expeditions to the
Moon, edited by
- Edgar M. Cortright, NASA SP; 350, Washington, DC, 1975 )
- The trip was marked by discomfort beyond the lack of food
and water. Sleep was almost impossible because of the cold. When
the electrical systems were turned off, the spacecraft lost and
important source of heat. The temperature dropped to 38 F and
condensation formed on all the walls.
- A most remarkable achievement of Mission Control was quickly
developing procedures for powering up the CM after its long cold
sleep. Flight controllers wrote the documents for this innovation in
three days, instead of the usual three months. The Command Module was
cold and clammy at the start of power up. The walls, ceiling, floor,
wire harnesses, and panels were all covered with droplets of water. It
was suspected conditions were the same behind the panels. The chances
of short circuits caused apprehension, but thanks to the safeguards
built into the command module after the disastrous
Apollo-1 fire in
January 1967, no arcing took place. The droplets furnished one
sensation as we decelerated in the atmosphere: it rained inside the
- Four hours before landing, the crew shed the service module;
Mission Control had insisted on retaining it until then because
everyone feared what the cold of space might do to the unsheltered CM
heat shield. Photos of the Service Module showed one whole panel
missing, and wreckage hanging out, it was a sorry mess as it drifted
away. Three hours later the crew left the Lunar Module Aquarius and
then splashed down gently in the Pacific Ocean near Samoa,
- After an intensive investigation, the
Apollo 13 Accident Review
Board identified the cause of the explosion. In 1965 the CM had
undergone many improvements, which included raising the permissible
voltage to the heaters in the oxygen tanks from 28 to 65 volts DC.
Unfortunately, the thermostatic switches on these heaters weren't
modified to suit the change. During one final test on the launch pad,
the heaters were on for a long period of time. "This subjected the
wiring in the vicinity of the heaters to very high temperatures (1000
F), which have been subsequently shown to severely degrade teflon
insulation. The thermostatic switches started to open while
powered by 65 volts DC and were probably welded shut." Furthermore,
other warning signs during testing went unheeded and the tank, damaged
from 8 hours overheating, was a potential bomb the next time it was
filled with oxygen. That bomb exploded on April 13, 1970 -- 200,000
miles from Earth.
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