$Unique_ID{bob00977}
$Pretitle{}
$Title{Apollo Expeditions To The Moon
Chapter 13: 'Houston, We've Had A Problem'}
$Subtitle{}
$Author{Lovell, James A.}
$Affiliation{NASA}
$Subject{lm
hours
apollo
oxygen
tank
module
cm
mission
time
water
see
pictures
see
figures
}
$Date{1975}
$Log{See SM Set Adrift*0097701.scf
See Apollo 13 Splashdown*0097702.scf
}
Title:       Apollo Expeditions To The Moon
Author:      Lovell, James A.
Affiliation: NASA
Date:        1975

Chapter 13: "Houston, We've Had A Problem"

     Since Apollo 13 many people have asked me, "Did you have suicide pills on
board?" We didn't, and I never heard of such a thing in the eleven years I
spent as an astronaut and NASA executive.

     I did, of course, occasionally think of the possibility that the
spacecraft explosion might maroon us in an enormous orbit about the Earth - a
sort of perpetual monument to the space program.  But Jack Swigert, Fred
Haise, and I never talked about that fate during our perilous flight.  I guess
we were too busy struggling for survival.

     Survive we did, but it was close.  Our mission was a failure but I like
to think it was a successful failure.

     Apollo 13, scheduled to be the third lunar landing, was launched at 1313
Houston time on Saturday, April 11, 1970; I had never felt more confident. On
my three previous missions, I had already logged 572 hours in space, beginning
with Gemini 7, when Frank Borman and I stayed up 14 days - a record not
equaled until Skylab.

     Looking back, I realize I should have been alerted by several omens that
occurred in the final stages of the Apollo 13 preparation.  First, our command
module pilot, Ken Mattingly, with whom Haise and I had trained for nearly two
years, turned out to have no immunity to German measles (a minor disease the
backup LM pilot, Charlie Duke, had inadvertently exposed us to).  I argued to
keep Ken, who was one of the most conscientious, hardest working of all the
astronauts.  In my argument to Dr. Paine, the NASA Administrator, I said,
"Measles aren't that bad, and if Ken came down with them, it would be on the
way home, which is a quiet part of the mission.  From my experience as command
module pilot on Apollo 8, I know Fred and I could bring the spacecraft home
alone if we had to." Besides, I said, Ken doesn't have the measles now, and he
may never get them. (Five years later, he still hadn't.)

     Dr. Paine said no, the risk was too great.  So I said in that case we'll
be happy to accept Jack Swigert, the backup CMP, a good man (as indeed he
proved to be, though he had only two days of prime-crew training).

     The second omen came in ground tests before launch, which indicated the
possibility of a poorly insulated supercritical helium tank in the LM's
descent stage.  So we modified the flight plan to enter the LM three hours
early, in order to obtain an on-board readout of helium tank pressure.  This
proved to be lucky for us because it gave us a chance to shake down this odd-
shaped spacecraft that was to hold our destiny in its spidery hands.  It also
meant the LM controllers were in Mission Control when they would be needed
most.

     Then there was the No. 2 oxygen tank, serial number 10024X-TA0009.  This
tank had been installed in the service module of Apollo 10, but was removed
for modification (and was damaged in the process of removal).  I have to
congratulate Tom Stafford, John Young, and Gene Cernan, the lucky dogs, for
getting rid of it.

     This tank was fixed, tested at the factory, installed in our service
module, and tested again during the Countdown Demonstration Test 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 its idiot twin 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 de power from the ground-support equipment to dissipate the oxygen.

     With the wisdom of hindsight, I should have said, "Hold it.  Wait a
second.  I'm riding on this spacecraft.  Just go out and replace that tank."
But the truth is, I went along, and I must share the responsibility with many,
many others for the $375 million failure of Apollo 13.  On just about every
spaceflight we have had some sort of failure, but in this case, it was an
accumulation of human errors and technical anomalies that doomed Apollo 13.

     At five and a half minutes after liftoff, Swigert, Haise, and I 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 us in orbit.  No problem: the S-IVB had plenty of fuel.

     The first two days we 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 we finished a 49-minute TV broadcast showing
how comfortably we lived and worked in weightlessness, I pronounced the
benediction: "This is the crew of Apollo 13 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."

     On the tapes I sound mellow and benign, or some might say fat, dumb, and
happy.  A pleasant evening, indeed!  Nine minutes later the roof fell in;
rather, oxygen tank No. 2 blew up, causing No. 1 tank also to fail.  We came
to the slow conclusion that our normal supply of electricity, light, and water
was lost, and we were about 200,000 miles from Earth.  We did not even have
power to gimbal the engine so we could begin an immediate return to 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." I 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 told us we had lost two of our three fuel cells,
which were our prime source of electricity.  Our first thoughts were ones of
disappointment, since mission rules forbade a lunar landing with only one fuel
cell.

     With warning lights blinking on, I checked our situation; the quantity
and pressure gages for the two oxygen tanks gave me cause for concern.  One
tank appeared to be completely empty, and there were indications that the
oxygen in the second tank was rapidly being depleted.  Were these just
instrument malfunctions?  I was soon to find out.

     Thirteen minutes after the explosion, I 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," I reported
to Houston.  Jack Lousma, the CapCom replied, "Roger, we copy you venting." I
said, "It's a gas of some sort."

     It was a gas - oxygen - escaping at a high rate from our second, and
last, oxygen tank.  I am told that some amateur astronomers on top of a
building in Houston could actually see the expanding sphere of gas around the
spacecraft.

Arranging for Survival

     The knot tightened in my stomach, and all regrets about not landing on
the Moon vanished.  Now it was strictly a case of survival.

     The first thing we did, even before we discovered the oxygen leak, was to
try to close the hatch between the CM and the LM.  We reacted spontaneously,
like submarine crews, closing the hatches to limit the amount of flooding.
First Jack and then I tried to lock the reluctant hatch, but the stubborn lid
wouldn't stay shut!  Exasperated, and realizing that we didn't have a cabin
leak, we strapped the hatch to the CM couch.

     In retrospect, it was a good thing that we kept the tunnel open, because
Fred and I would soon have to make a quick trip to the LM in our fight for
survival.  It is interesting to note that days later, just before we
jettisoned the LM, when the hatch had to be closed and locked, Jack did it -
easy as pie.  That's the kind of flight it was.

     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, it was obvious that we were going to
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."

     A lot has been written about using the LM as a lifeboat after the CM has
become disabled.  There are documents to prove that the lifeboat theory was
discussed just before the Lunar Orbit Rendezvous mode was chosen in 1962.
Other references go back to 1963, but by 1964 a study at the Manned Spacecraft
Center concluded: "The LM [as lifeboat] ... was finally dropped, because no
single reasonable CSM failure could be identified that would prohibit use of
the SPS." Naturally, I'm glad that view didn't prevail, and I'm thankful that
by the time of Apollo 10, the first lunar mission carrying the LM, the LM as a
lifeboat was again being discussed.  Fred Haise, fortunately, held the
reputation as the top astronaut expert on the LM - after spending fourteen
months at the Grumman plant on Long Island, where the LM was built.

     Fred says: "I never heard of the LM being used in the sense that we used
it.  We had procedures, and we had trained to use it as a backup propulsion
device, the rationale being that the thing we were really covering was the
failure of the command module's main engine, the SPS engine.  In that case, we
would have used combinations of the LM descent engine, and in some cases, for
some lunar aborts, the ascent engine as well.  But we never really thought and
planned, and obviously, we didn't have the procedures to cover a case where
the command module would end up fully powered down."

     To get Apollo 13 home would require a lot of innovation.  Most of the
material written about our mission describes the ground-based activities, and
I certainly agree that without the splendid people in Mission Control, and
their backups, we'd still be up there.

     They faced a formidable task.  Completely new procedures had to be
written and tested in the simulator before being passed up to us.  The
navigation problem was also theirs; essentially how, when, and in what
attitude to burn the LM descent engine to provide a quick return home.  They
were always aware of our safety, as exemplified by the jury-rig fix of our
environmental system to reduce the carbon dioxide level.

     However, I would be remiss not to state that it really was the teamwork
between the ground and flight crew that resulted in a successful return.  I
was blessed with two shipmates who were very knowledgeable about their
spacecraft systems, and the disabled service module forced me to relearn
quickly how to control spacecraft attitude from the LM, a task that became
more difficult when we turned off the attitude indicator.

[See SM Set Adrift: Blast-gutted service module was set adrift from the
combined command module and lunar module just four hours before Earth reentry.]

Fifteen Minutes of Power left

     With only 15 minutes of power left in the CM, CapCom told us to make our
way into the LM.  Fred and I quickly floated through the tunnel, leaving Jack
to perform the last chores in our forlorn and pitiful GM that had seemed such
a happy home less than two hours earlier.  Fred said something that strikes me
as funny as I read it now: "Didn't think I'd be back so soon." But nothing
seemed funny in real time on that 13th of April, 1970.

     There were many, many things to do.  In the first place, did we have
enough consumables to get home?  Fred started calculating, keeping in mind
that the LM was built for only a 45-hour lifetime, and we had to stretch that
to 90.  He had some data from previous LM's in his book - average rates of
water usage related to amperage level, rate of water needed for cooling.  It
turned out that we had enough oxygen.  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 we started with.)

     We had 2181 ampere hours in the LM batteries.  We thought that was enough
if we turned off every electrical power device not absolutely necessary.  We
could not count on the precious GM batteries, because they would be needed for
reentry after the LM was cast off.  In fact, the ground carefully worked out a
procedure where we charged the GM batteries with LM power.  As it turned out,
we reduced our energy consumption to a fifth of normal, which resulted in our
having 20 percent of our LM electrical power left when we jettisoned Aquarius.
We did have one electrical heart-stopper during the mission.  One of the CM
batteries vented with such force that it momentarily dropped off the line.  We
knew we were finished if we permanently lost that battery.

     Water was the real problem.  Fred figured that we would run out of water
about five hours before we got back to Earth, which was calculated at around
151 hours.  But even there, Fred had an ace in the hole.  He knew we had a
data point from Apollo 11, which had not sent its LM ascent stage crashing
into the Moon, as subsequent missions did.  An engineering test on this
vehicle showed that its mechanisms could survive seven or eight hours in space
without water cooling, until the guidance system rebelled at this enforced
toasting.  But we did conserve water.  We cut down to six ounces each per day,
a fifth of normal intake, and used fruit juices; we ate hot dogs and other
wet-pack foods when we ate at all. (We lost hot water with the accident and
dehydratable food is not palatable with cold water.) Somehow, one doesn't get
very thirsty in space, and we became quite dehydrated.  I set one record that
stood up throughout Apollo: I lost fourteen pounds, and our crew set another
by losing a total of 31.5 pounds, nearly 50 percent more than any other crew.
Those stringent measures resulted in our finishing with 28.2 pounds of water,
about 9 percent of the total.

     Fred had figured that we had enough lithium hydroxide canisters, which
remove carbon dioxide from the spacecraft.  There were four cartridge from the
LM, and four from the backpacks, counting backups.  But he forgot that there
would be three of us in the LM instead of the normal two.  The LM was designed
to support two men for two days.  Now it was being asked to care for three men
nearly four days.

A Square Peg in a Round Hole

     We would have died of the exhaust from our own lungs if Mission Control
hadn't come up with a marvelous fix.  The trouble was the square lithium
hydroxide canisters from the CM would not fit the round openings of those in
the LM environmental system.  After a day and a half in the LM a warning light
showed us that the carbon dioxide had built up to a dangerous level, but the
ground was ready.  They had thought up a way to attach a CM canister to the LM
system by using plastic bags, cardboard, and tape - all materials we had on
board.  Jack and I put it together: just like building a model airplane.  The
contraption wasn't very handsome, but it worked.  It was a great improvisation
- and a fine example of cooperation between ground and space.

     The big question was, "How do we 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, we had made the normal midcourse
correction, which would take us out of a free-return-to-Earth trajectory and
put us on our lunar landing course.  Now we had to get back on that free-
return course.  The ground-computed 35-second burn, by an engine designed to
land us on the Moon, accomplished that objective 5 hours after the explosion.

     As we approached the Moon, the ground informed us that we would have to
use the LM descent engine a second time; this time a long 5-minute burn to
speed up our return home.  The maneuver was to take place 2 hours after
rounding the far side of the Moon, and I was busy running down the procedures
we were to use.  Suddenly, I noticed that Swigert and Haise had their cameras
out and were busy photographing the lunar surface.  I looked at them
incredulously and said, "If we don't make this next maneuver correctly, you
won't get your pictures developed!" They said, "Well, you've been here before
and we haven't." Actually, some of the pictures these tourists took turned out
to be very useful.

     It was about this time that I said, "Boys, take a good look at the Moon.
It's going to be a long time before anybody gets up here again." Later on I
was accused of sabotaging Apollo; poor Dr. Paine had to explain that I didn't
really mean it, and the space program would go on.  The Senate Space Committee
asked me about it a week after we got back.  Actually, I didn't mean that
remark to be public. (I later learned that, unknown to us, we had had a hot
mike for about 45 minutes.) Nonetheless, it was 9 months before Apollo 14 was
launched.

     We had many crises on Apollo 13, but the biggest heart-stopper has hardly
been noticed, partly because the transcription released to the press was
garbled, and partly because there wasn't much point in talking about a crisis
that had been averted earlier.  It occurred prior to the second maneuver I
mentioned earlier; we called it P.C. + 2 (pericynthian + 2 hours).

     We had transferred the CM platform alignment to the LM, but we had to
make sure that this alignment was accurate before we made the long P.C. + 2
burn.  Ordinarily it is simple to look through the sextant device, called the
Alignment Optical Telescope, find a suitable navigation star, and with the
help of our computer verify the guidance platform's alignment.  But traveling
with us was a swarm of debris from the ruptured service module.  The sunlight
glinting on these bits of junk - I called them false stars - made it
impossible to sight a real star.

     So what to do? If we couldn't verify the accuracy of the alignment, we
didn't have a way to make an accurate burn, or to align the CM platform for
reentry.  In other words, the ground would have no accurate way to tell us the
correct attitude to make the proper maneuvers to return home.

     A genius in Mission Control came up with the idea of using the Sun to
check the accuracy of our alignment.  No amount of debris could blot out that
star!  Its large diameter could result in considerable error, but nobody had a
better plan.

     I rotated the spacecraft to the attitude Houston had requested.  If our
alignment was accurate, the Sun would be centered in the sextant.

     When I looked through the AOT, the Sun just had to be there.  It really
had to be.  And it was.  At 73:46 hours the air-to-ground transcript sounds
like a song from "My Fair Lady":

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 damned nervous.  And I remember the exhilaration running
through me: My God, that's kinda 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.
Neither did we, as crew members, refer to it as a crisis in our press
conference nor in later articles.

     The alignment with the Sun proved to be less than a half a degree off.
Hallelujah!  Now we knew we 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.
We weren't exactly home free: we had a dead service module, a command module
with no power, and a lunar module that was a wonderful vehicle to travel home
in, but unfortunately didn't have a heat shield required to enter the Earth's
atmosphere.  But all we needed now was a continuation of the expertise we
seemed blessed with, plus a little luck.

Tired, Hungry, Wet, Cold, Dehydrated

     The trip was marked by discomfort beyond the lack of food and water.
Sleep was almost impossible because of the cold.  When we turned off the
electrical systems, we lost our source of heat, and the Sun streaming in the
windows didn't much help.  We were as cold as frogs in a frozen pool,
especially Jack Swigert, who got his feet wet and didn't have lunar overshoes.
It wasn't simply that the temperature dropped to 38 degrees F: the sight of
perspiring walls and wet windows made it seem even colder.  We considered
putting on our spacesuits, but they would have been bulky and too sweaty.  Our
teflon-coated inflight coveralls were cold to the touch, and how we longed for
some good old thermal underwear.

     The ground, anxious not to disturb our homeward trajectory, told us not
to dump any waste material overboard.  What to do with urine taxed our
ingenuity.  There were three bags in the command module; we found six little
ones in the LM, then we connected a PLSS condensate tank to a long hose, and
finally we used two large bags designed to drain remaining water out of the
PLSS's after the first lunar EVA.  I'm glad we got home when we did, because
we were just about out of ideas for stowage.

     A most remarkable achievement of Mission Control was quickly developing
procedures for powering up the CM after its long cold sleep.  They wrote the
documents for this innovation in three days, instead of the usual three
months.  We found the CM a cold, clammy tin can when we started to power up.
The walls, ceiling, floor, wire harnesses, and panels were all covered with
droplets of water.  We suspected conditions were the same behind the panels.
The chances of short circuits caused us apprehension, to say the least.  But
thanks to the safeguards built into the command module after the disastrous
fire in January 1967, no arcing took place.  The droplets furnished one
sensation as we decelerated in the atmosphere: it rained inside the CM.

     Four hours before landing, we 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.  I'm glad we weren't able
to see the SM earlier.  With one whole panel missing, and wreckage hanging
out, it was a sorry mess as it drifted away.

     Three hours later we parted with faithful Aquarius, rather rudely,
because we blasted it loose with pressure in the tunnel in order to make sure
it completely cleared.  Then we splashed down gently in the Pacific Ocean near
Samoa, a beautiful landing in a blue-ink ocean on a lovely, lovely planet.

     Nobody believes me, but during this six-day odyssey we had no idea what
an impression Apollo 13 made on the people of Earth.  We never dreamed a
billion people were following us on television and radio, and reading about us
in banner headlines of every newspaper published.  We still missed the point
on board the carrier Iwo Jima, which picked us up, because the sailors had
been as remote from the media as we were.  Only when we reached Honolulu did
we comprehend our impact: there we found President Nixon and Dr. Paine to meet
us, along with my wife Marilyn, Fred's wife Mary (who being pregnant, also had
a doctor along just in case), and bachelor Jack's parents, in lieu of his
usual airline stewardesses.

     In case you are wondering about the cause of it all, I refer you to the
report of the Apollo 13 Review Board, issued after an intensive investigation.
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 degrees_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.

[See Apollo 13 Splashdown: The charred Apollo 13 command module splashed down
less than four miles from the recovery ship USS Iwo Jima.]