Director Glynn Lunney expected a quiet night on the console as he
began his shift on the evening of April 13, 1970. But, soon after,
while the Apollo XIII crew performed a routine procedure, an explosion
occurred onboard their spacecraft. For the next 14 hours, Lunney says
he experienced what he considers to be the best piece of operations
work he ever did or could hope to do.
his description of how the incident “posed a continuous demand
for the best decisions often without hard data and mostly on the basis
of judgment, in the face of the most severe in-flight emergency faced
thus far in manned space flight.” In this narrative he shares
“through one decision, one choice, and one innovation at a time,”
the team at Mission Control at the Manned Spacecraft Center in Houston
worked together to bring the Apollo XIII crew safely home.
the Apollo flight campaign for the exploration of the Moon,
Apollo XIII was planned as the
third lunar landing mission.
It was targeted to land and explore a large crater
named Fra Mauro in the Imbrium Basin.
the Countdown Demonstration Test [CDDT], which started on March 13,
1970, a detanking of the two cryogenic tanks commenced. The first
tank quantity dropped normally while the other tank only drained eight
percent out—a very small amount. This was attributed to an internal
leak path (probably caused by some separation of the fill line coupling
from the fill line) and it prevented a normal detanking. There had
been an earlier incident in handling the tank, well before installation
in the vehicle, and it had dropped two inches. This supported the
scenario of a mechanically caused separation and an internal leak
Now, for the first time, the heaters in the tank were used to expel
the lox (liquid oxygen) by boiling it off.
Back in 1966, the voltage for the heater was increased from 28 volts
to 65 volts in order to aid in faster pressurization. The 65 volts
were supplied via a “ground test-only” harness. However,
the 65 volt GSE (ground support equipment) harness also powered two
thermostatic switch circuits; their function was to protect the heater
assembly and tank temperature from exceeding 80 F by opening and unpowering
the heater circuit. But, the thermostatic switches were never modified,
qualified or acceptance tested at 65 volts. It was a serious error
in our system of making changes and a reminder of how seemingly minor
changes can propagate into something much worse than the situation
you think you are improving.
As the tank was drained with the heaters on, the tank warmed and the
thermostatic switches tried to open but were welded closed by the
65 volt arcing. Therefore, the heaters continued to draw power for
hours and the Teflon insulation protecting the fan motor wires routed
through the heater assembly were mostly melted and destroyed.
A partial fill test was conducted on March 30 with the same signature
of slow drain of the second tank. It was concluded that the leak was
internal to the tank—partially refilling instead of draining—and
we would not be draining the tank during flight. Therefore, there
was not sufficient reason to replace the tank.
And so, the stage was set for the failure to come during Apollo XIII.
It also became more apparent that the media coverage and perhaps the
public interest had cooled noticeably from the run up to Apollo XI.
The timing was ironic because after some long period of deliberation—maybe
years—NASA had agreed to allow two journalists to sit in a small
booth within the viewing room, overlooking the floor of the Mission
Control Center [MCC]. This was never much of an issue for us because
the media had full-time access to the air/ground loop with astronauts/capcom
traffic and the flight director loop. So the granting of access added
a real visual of the room, available to two journalists and, presumably,
more personal than the ever present TV coverage of the operations
floor of MCC.
Certainly, to me, and I would say most others, it simply did not matter.
We were familiar with some regular visitor traffic through the viewing
room and we all just ignored it. The journalists' presence made no
difference to us. However, it was disappointing to some that the intensity
of coverage diminished after Apollo XI. I thought it was a somewhat
natural reaction by the media and it did not bother me. The intensity
of Apollo XI media coverage could not be maintained indefinitely.
The Apollo XIII crew was Jim Lovell, Fred Haise, and Ken Mattingly
through many of our training runs. However, late in the flow, Ken
was replaced by the backup Jack Swigert as the CM [Command Module]
pilot, because of a medical concern for Ken's exposure to a child
with measles. Jim Lovell was the veteran of two Gemini flights and
Apollo VIII. As with all other astronauts, the term "rookie"
is really not applicable to the other two crewmen because of their
total involvement and training in all the steps leading to this flight
and their test flight pilot experience. For example, Fred Haise made
it his business to know all about the LM, even to knowing where all
the critical wires in the LM [Lunar Module] were routed behind the
close-out panels and how to use that knowledge for a hot start if
necessary. Jack Swigert was the astronaut office initiator of the
malfunction procedure methodology for the CSM [Command Service Module].
It turned out that Ken never developed measles, but a bias to the
cautious side led to his being bumped from the flight and later assigned
to Apollo XVI. Although never done before, the CM pilot was the easiest
person to swap out because his critical role at the Moon was the solo
tending of the CSM while the other two crewmen landed. Nevertheless,
I am sure it gave Jim and Deke [Slayton, Chief of the Astronaut Office]
a serious round of discussions.
Milt Windler was the lead flight director for XIII and was on duty
for the launch phase. The countdown was normal and the Saturn V [SIVB]
rumbled off the pad at 2:13 pm EST on April 11, 1970. Then, shades
of Apollo VI, the second stage center engine shut down more than two
minutes early. The Trench was able to verify that the guidance would
perform well and the vehicle should burn all the propellant through
the other four engines and end up close to a normal orbit, which it
Then, a GO for TLI [trans lunar injection], the SIVB burned and we
had the prospect of a quiet coast out to the Moon.
I came out to MCC for my shift as Black Team Flight Director at about
8:30 pm CST on the evening of April 13, 1970, about two and a half
days into the flight. I expected a quiet night on the console. Gene
Kranz's White Team was coming to the end of a long day for the crew
that ended with a narrated TV tour of the LM. The crew was back in
the CSM getting ready for a sleep period. After reading the Flight
Director Log and catching up with Gene, I went on a walk-around through
the back rooms to take the pulse of the team.
As a routine procedure at that time, the crew was asked to turn on
the fans in the cryo tanks to get a uniform mixture in the tanks for
the sleep period. The vehicle was 205,000 miles from Earth, 80 percent
of the way to the Moon and just beginning to fall into the influence
of the lunar gravity.
And this was the moment when the bare, and now-powered, fan wires
contacted a metal surface in the tank, discharged in the oxygen rich
environment of the tank, and caused an explosion.
55:55 GET (Ground Elapsed Time [GET] since liftoff) The
crew report of “Houston, we've had a problem here” changed
the narrative from the start of a crew sleep period to something else—uneasy,
but still not clear. Somebody turned to me and said, “Glynn,
you may want to get back to the front room, NOW.” I did and
plugged in at the flight director console to hear a confusing array
of multiple indications of problems such as, “Main bus B under
volt, fuel cell disconnect, O2 tank low pressure.” At first,
it was necessary to be careful and rule out the possibility that some
electrical/instrumentation problem was creating the appearance of
a bad situation.
56:14 GET ( :19 minutes since problem start) The
fact of a really serious condition began to dawn on the team as the
crew reported the spacecraft venting particles as seen out the window
(that's where the O2 is going and why the O2 tank pressure is so low,
and that could be associated with the loud bang initially reported
by the crew.) We soon realized that this was not a matter of preserving
the landing mission, but this was now about saving the crew. Gene's
team struggled to save what they could of the CSM cryo/fuel cell systems
for further use and to reconfigure some of the systems so they would
operate properly in the face of the electrical system failures. A
CSM power down was started at 56: 22 GET and reached a level of 41
56:25 GET ( :30 minutes since problem start) EECOM
was concluding that this was not an instrumentation problem and two
fuel cells were indeed lost. At about this point, the crew became
involved in trying to control some unexpected vehicle rates which
were assumed to be due to the venting.
56:31 GET ( :36 minutes since problem start) The
pressure in the other oxygen tank, O2#1, was reported low and still
dropping. More power down was needed. MCC had the crew turn on tank
heaters and then the fans to try to arrest the pressure loss, but
to no avail. Minutes later, the CM O2 surge tank was isolated to conserve
it for entry. We had only one fuel cell and its supply tank of cryo
oxygen was expected to go to zero in two hours or less. It was near
time to start using the LM as a lifeboat. But a few things remained
to be done first.
In trying to find a way to assist Gene and his team, I was already
engaged with Jerry Bostick who was sorting options with the Trench
for how to return home from this point. Jerry guided the Trench team
through the options. John Llewellyn was also on scene to ride shotgun
with Tom Weichel. John was able to focus on this downstream decision
while Tom was occupied with the immediate aftermath of the problem.
It is very easy to understand that there was a very strong sentiment
in MCC not to go to the Moon, but to turn around and get on the way
Understandable as that attitude was, it would take about 6000 fps
to perform the necessarily very large maneuver. The only propulsion
system with that much power was the Service Propulsion System [SPS]
located in the service module. We had some real concern that the Service
Module had been damaged in whatever had caused the original loud bang.
But more importantly, there was a limited amount of power in the CSM
entry batteries which would have to be used for a powered-up SPS propulsion
maneuver, about 50 amps.
A major burn is done normally with the higher power capability of
one or more fuel cells, but the last fuel cell was fading fast. The
necessary electrical power drain would probably come close to depleting
the small entry batteries (the only power available for entry), and
we did not yet know if they could be recharged. As another decisive
negative consideration, in order to make the burn achieve 6000 fps,
it would be necessary to jettison the mass of the LM descent stage,
which contained most of the batteries and cooling water needed for
the trip home.
I summarized this situation for Gene, as described above, with Jerry's
help and the Trench confirming the situation and our assessment of
options. This was not even a close call. We had to go around the Moon.
56:48 GET ( :53 minutes since problem start) Gene
agreed and announced the go-around the Moon decision to the team.
57:05 GET ( 1 hour:10 minutes since problem start)
With full recognition of how demanding this situation was, the Black
Team and I came on duty. Positions were manned by Jack Lousma at capcom,
Larry Keyser at AFD, Gary Scott and Ed Fendell at INCO, Bill Boone
and Maurice Kennedy at FIDO, Tom Weichel at Retro, Gary Renick and
Will Presley at GUIDO, Merlin Merritt at TELMU, Hal Loden at LM Control,
Clint Burton at EECOM, Jack Kamman at GNC, and Spencer Gardner and
Elvin Pippert at FAO.
Chris Kraft and Sig Sjoberg were also in there by this time. All the
other off-shift flight controllers and astronauts gathered to help
within less than an hour of the problem. (Consoles had four jacks
for headsets to plug in and they were all occupied.) This flight control
team was a solid set of operators, but hardly any had been in this
kind of circumstance. Besides the flight controllers, we also had
the best brains available through our offline SPAN communications
and data network with all of the engineering and program organizations,
both in NASA and industry, and from all regions of the country.
The MCC was full. Even so, the Comm loop discipline was good. No illusions
by now—we all knew that this was a very big hill to climb. It
was time to get on with it. The situation was:
• A loud bang was reported at the start of this problem and
eventually the crew reported particles venting from the Service Module.
• O2 tank #2 was at 0 pressure. O2 tank #1 was predicted to
last no more than 2 hours.
• Fuel cells 1 and 3 were not supplying power.
• Main bus B and AC bus 2 were zero, since both were fed by
fuel cell 3.
• Considerable reconfiguration had been performed to get enough
thrusters on main Bus A.
• The trajectory was not on a free return to the entry corridor
and it needed correction.
To help in understanding our response, actions can be considered in
THE CONFIGURATION OF THE SPACECRAFT SYSTEMS. Sometimes configuration
choices were driven by troubleshooting problems (e.g. leak isolation,
switching redundant paths, preserving capability, etc.) to support
a mission need (e.g. a propulsion maneuver, a power down, the optimum
control system capability, etc.). The mission need to operate within
the reduced consumables also stressed the configuration choices well
beyond the normal. The choices also required closer coordination among
the flight controller positions in the MCC because the window was
much narrower for an integrated solution (balancing the demands of
propulsion, electrical power, time, coolant water, guidance equipment,
RETURN HOME STEPS. These were the necessary mission steps to safely
return the crew. In the minute-by-minute voice traffic within MCC
and with the crew, the return home steps provided an overall mission
framework. But, the majority of time and interactions was spent evaluating,
deciding and implementing the spacecraft configuration choices to
stabilize and/or improve our posture to support the crew and accomplish
the return steps. Burned into us from years of training and operations
was the CARDINAL rule: Don't screw anything up and make
the situation worse than it already is.
It also helps
to understand the evolution of the return home plan as an incremental
process. We did not begin by having a comprehensive plan, but rather
took steps as we judged them to be necessary, appropriate, or kept
us with the best range of forward options.
Think of the process as the fog clearing enough to commit to the next
step. For example, the first of the RETURN HOME steps was the decision
at 56:48 GET to go-around the Moon rather than attempting a direct
return. Step #1 was driven by a fact- based analysis of options illustrating
that the go-around option was the only workable one. Some of the next
steps were more based on the judgment (without a full factual analysis)
of what was best. I will highlight each of the return-home steps as
our shift and the flight progressed, with the first one being Gene's
earlier decision to swing around the Moon.
With the vehicle rates under control with a new RCS configuration,
the Black Team first focused on the last-ditch steps to try to save
some of the CSM cryo-fuel cell capability. The last step was to close
the reactant valves to the non-performing two fuel cells in an attempt
to isolate the possibility of an O2 leak inside the fuel cell itself.
Once closed, the fuel cell was without the fuel to run and could not
be restarted. No joy on the first cell. Then, the second one ended
up with the same negative result. The O2 leak continued.
57:35 GET ( 1 hour:40 minutes since problem start) The
two LM crew members were making their entry into the LM at the same
time we were calling up that recommendation. “We're already
on our way,” was the reply. At this time, we had one good fuel
cell #2 but the oxygen pressure to feed it was still dropping. The
crew began the initial activation of the LM designed to get the batteries,
life support systems, and communication/instrumentation systems online.
MCC received the initial LM telemetry signal at 57:57 GET. (In managing
and prioritizing the flow of comm traffic, Jack Lousma was a pillar
of stability for this team over the course of a very long night.)
During the power-up, I had a short time to consider options. My first
strong inclination was to power down quickly, conserve LM consumables,
and work out a plan. But, I also had serious concern that the venting
particles would preclude getting a good guidance platform alignment
for the burns that would be required later. Tom Stafford was intense
about getting and maintaining the alignment in the LM. There were
confirming nods from Jack Lousma and other Apollo crewmen. This was
now our only opportunity to get the CSM inertial guidance alignment
transferred to the LM guidance system, even if we later decided that
we did not want to use it and powered the LM platform down. I decided
to take the time and electrical power from both vehicles to accomplish
that transfer and then decide what was next. If not done now, this
opportunity would be lost and no longer available. It was much too
early to foreclose this option going forward.
57:54 GET ( 1 hour: 59 minutes since problem start)
The CMP powered down as much in the CSM as he could while keeping
the CSM guidance system up. Because of the decreasing O2, Clint Burton
at EECOM was watching to see a degradation in fuel cell 2 in order
to know when to put an entry battery on to support the electrical
bus. We intended to stay 'up' in the CSM until a LM guidance alignment
was transferred. Once we were on entry battery A, we wanted to minimize
the number of amp hours withdrawn from it since we did not know if
we could charge it from the LM for later use. The alignment transfer
itself was a tedious process of crew/MCC coordination and the reading
and checking of a lot of numbers as they were entered into the LM
guidance computer. During the period of transferring the alignment,
there was a short period with neither of the attitude control systems
on. This was quickly recognized and corrected.
Around the time of these final CSM closeout steps, I had a brief period
when the severity of the problem really struck home. For the first
and only time in 10 years of console experiences in training and actual
flights, I had the sense of the bottom falling out from under me and
my stomach heading for that dark hole. I would like to believe that
it was due to an acute intellectual awareness of the “Abandon
Ship” situation, but the response to myself—Holy Shit.
I can't believe this is really happening—was all emotional,
not intellectual. Scary. But the 10 years of experience kicked in
and it took about 10-20 seconds for me to return from that place.
Nobody else even seemed to notice.
58:40 GET ( 2 hours:45 minutes since problem start)
Jack Lousma helped get the team back to tailoring an existing checklist
for LM power-up; it was now time to turn off the CSM power. We had
used about 20 amp-hours or 15 percent of total entry battery power
before power-down. The CSM cabin was going to get very cold and uncomfortable
and we still needed Odyssey to get home.
I considered the decision to transfer the CSM platform alignment to
the LM as key to maintaining our future options and it was RETURN
HOME Step #2 in our still evolving plan. We still had the choice to
power it all down and reconsider later. At this point, keeping the
LM alignment was a good trade for accurate, reliable control of future
propulsion burns against a modest amount of LM power being used for
a near-term midcourse maneuver in a few hours to get back on free
return. The free return midcourse would also verify that the alignment
and the propulsion systems were in good shape. Also significant, the
fact of being on a free return should be a psychological lift for
the entire team.
With respect to using the LM consumables, my judgment was that this
team would find a way to stretch a nominal 2+days of powered up LM
consumables to a 4 day, powered down survival mission. It still made
us all nervous, some more than others. And after the midcourse in
the next 2 hours, we would have more accurate consumable forecasts
available to decide whether to power down or stay up after that. This
was a good example of the incremental development of the return-home
plan. Take the bird-in-hand especially when the tradeoff—in
this case, the consumable cost—was reasonably low.
58:54 GET ( 2 hours: 59 minutes since problem start)
Jim Lovell reported, “I still see a lot of particles and I cannot
identify any constellations, at least in this attitude.” This
strengthened my resolve to save the alignment reference in the LM
until the propulsion maneuver and consumable picture became more clear.
At about this time, we had more time to confer with the flight controllers
studying the return-to-Earth options.
The LM coolant water was the critical item and the initial cooling
water usage was high, about double what was normal for the electrical
load, because it was cooling down the entire loop. The usage rate
would soon slow down. But, the first estimates would have depleted
the coolant water by 94:00 GET at current usage rates, some 50 hours
short of what was needed. Obviously, this was not good enough but
the estimates also had been made for a very high power level in the
LM, about 35 amps, for the remainder of the flight. Both of these
assumptions were much too conservative. Merlin Merritt at the TELMU
position pressed for a quick power down. I told him, “Merlin,
I appreciate your concern, but I am still waiting for an overall plan
from Control on the control system options.”
In order to move the attention from conservation-only to the primary
objective of a safe return home, I selected what seemed to be the
most promising option of those provided by the Trench. Then I asked
for LM consumable forecasts, assuming a continued power-up but at
more nominal H2O usage rates. The power-up would continue until a
major propulsion burn at pericynthion (closest approach to the Moon)
plus 2 hours, and then reduce the LM power to 15 to 18 amps for most
of the trip home, allowing 2 midcourse opportunities. I asked for
a range of variations in power levels around that timeline so we did
not wait for “perfectly accurate” answers. For now, the
approach should be based on faster results including reasonable variations
in order to enable the selection of the return home plan. We knew
that the CO2 fix was needed, but definition of it was not urgent and
the engineering team was on it.
While that was being done, there was time to refine our near-term
maneuver options. We could do a midcourse correction quickly to establish
free return and then choose to power down or not. I decided to take
the option of getting on free return as soon as practical. We then
began to select a time for the midcourse which was adequate for the
team to assure proper checklist procedures. We offered 61 hours GET
and the crew wanted a little more time, settling on 61:30 GET.
61:30 GET ( 5 hours: 35 minutes since problem start)
The midcourse was performed and delivered a 40 ft/sec correction with
the descent engine. Burn parameters were nominal and the tracking
confirmed the maneuver. The accuracy of the burn also verified that
we had a good alignment in the LM. This decision to go ahead with
the midcourse to re-establish free return was RETURN HOME Step #3
and served as an emotional lift for the crew and team. We were back
on free return, but still a long way to go. LM current was decreased
from about 32 amps to 25 amps in the period before the PC+2 burn.
Through all this, Chris and Sig were present all the time and it was
so easy to communicate with them. They followed all the traffic on
the comm loops. Sometimes, we would sum up a situation and give them
a “how-I-am-thinking-about-this-subject” before it came
to decision time. Sometimes, the understanding was conveyed by a look
or a thumbs up or down. I don't really remember any questions that
they had as we went along. I do remember a strong feeling of support.
I always felt completely in sync with them, even with very little
Once the free return midcourse burn was performed, an attempt was
made to setup passive thermal control (PTC) to control the thermal
balance of the spacecraft. This was going to be attempted with its
usual difficulty made worse by the fact that we were doing this with
the LM control system for the first time versus the CSM as on past
missions. The PTC was designed to cycle cold (away from the Sun) and
hot environments (facing the Sun) uniformly around the CSM/LM stack
to avoid extreme temperatures anywhere. The technique was to stand
the stack perpendicular to the Earth/Sun plane and spin it slowly,
about one revolution every couple of hours, to spread the heating
and cooling throughout the vehicle in a uniform way. It is a delicate
maneuver in that the vehicle tends to wobble off like a top slowing
down and not spin on the same axis for very long.
63:05 GET ( 7 hours:10 minutes since problem start)
After more trajectory and consumable discussions, I was confident
enough to confirm the most reasonable return option in terms of propulsion,
configuration, and landing time and location. MCC passed a preliminary
advisory for a PC+ 2 hour LM descent maneuver of about 890 fps designed
to land at the mid-Pacific recovery site at 142:40 GET, 12 hours better
than the present free return landing time. These advisories were regularly
sent so that the crew always had the best return-home info, in case
of communication loss. This was RETURN HOME Step #4 (preliminary)
and basically the same plan we confirmed as the final plan to the
crew about 7 hours later.
63:20 GET ( 7hours:25 minutes since problem start)
We were able to soon reconfirm that the earlier advisory message sent
to the crew would have adequate consumables. The time margin for the
two most limiting consumables would be 20 hours of electrical power
and the water margin would be 12 hours. This all assumed a continued
power up through the PC 2 time of 79:30 GET, and then powering down
to a life support and communications mode using about 15.5 amps and
with 2 power-up midcourse opportunities. We had a workable plan and
expected that it would continue to improve as we had more chance to
At about this time, we got back to the CO2 removal concern, which
was not immediately urgent. SPAN reported that they were already working
with the Crew Systems Division on how to use the CSM canisters in
the LM and planning to test the configuration. They expected a solution
in a couple of shifts. I knew from past experience that they would
succeed. They were very good at improvising; no worry about that one.
63:50 GET ( 7hours:55 minutes after the start of problem)
The attempt to set up the rolling PTC was given up because
of the difficulty in setting up a stable, slowly rolling spacecraft.
With a crew man awake at all times, the simpler PTC attitude hold
for an hour and then roll 90 degrees to a new attitude for another
hour was selected. The Guidance team began looking ahead to later
darkness opportunities while in the shadow of the Moon to permit guidance
system alignment checks or a new Earth/Sun technique for checking
the present alignment. This Guidance initiative was typical of a fairly
steady stream of configuration choices and future possibilities to
consider and plan for. All shifts had some level of traffic like this
as the mission progressed.
SPAN was also considering the pros and cons of jettisoning the SM
in order to burn most of the descent fuel and achieve a one-day landing
earlier time of 118:00 GET time. The two concerns for this option
were the cold environment to which the head shield and the CM RCS
would be exposed and the fairly small amount of descent fuel which
would be left. None of us liked the idea of jettisoning the SM and
dealing with the uncertainty of the cold environment. Unless we could
get a lot more confidence, that option would not be exercised. Still,
there was not a real urgency to decide that issue at this time and
they continued with the analysis of that configuration.
67:00 GET (11:05 11 hours: 5 minutes since problem start)
Near the end of the Black Team shift, the consumable projections were
solid and MCC was comfortable with the plan. Three open issues were:
SM jettison, CO2 removal and the entry procedures. Gerry Griffin and
the Gold Team were coming on duty and were well up to speed because
they were following in MCC for hours before their on- duty call.
A number of flight controllers and I went to a press conference at
about 9 am CST for the regular change of shift briefing. At the press
conference, the decision on the exact return plan was left open because
we had a management briefing to discuss it scheduled after the press
conference. I have never been to a press conference when the press,
many of whom we knew well and by first names, was so supportive. They
all cared as much for the safety of the astronauts as any of us doing
69:30 GET ( 13 hours:35 minutes since problem start) A
meeting was held with all of the executive management from NASA HQs,
all the major NASA and contractor executives at JSC and representatives
from other centers and the DOD recovery manager. Gerry and I attended
and I recapped the events of the night before with the stipulation
that we did not know the exact root cause of the original problem.
But I did recount all the downstream effects and what the team did
to cope with them. This got us to our present posture, still about
10 hours to go before the PC+2 burn. Continuing with the RETURN HOME
options, they encompassed the total range of possibilities. All speed
up burns were scheduled right after the most efficient time, i.e.
behind the Moon, plus 2 hours to be well around the Moon and in sight
of our Earthbound communication coverage. The options were the same
as our earlier review at 63:05 which resulted in the preliminary plan
being selected and sent to the crew:
#1 No speed up maneuver, landing in Indian Ocean at 155 GET.
Option #2 Descent burn of 850 fps, landing in primary mid-Pacific
at 143 GET.
Option #3 Descent burn of 2000 fps, landing in South Atlantic at 133
Option #4 Descent burn of 4800 fps, landing in mid-Pacific at 118
GET. Requires SM jettison.
#5 SPS burn of 4800 fps, landing in mid-Pacific at 118 GET.
recovery capabilities were much stronger in the planned mid-Pacific
with a carrier and helicopters.
#1 was the longest return time to a difficult area with only aircraft
Option #2 was conservative on fuel, leaving a large reserve for midcourses,
best recovery posture, solid plan for consumables. RECOMMENDED.
Option #3 left LM descent prop nearly depleted, not much margin for
midcourses, South Atlantic recovery posture is only aircraft, no surface
ship coverage. Saves 10 hours over option #2. Not enough gain vs.
Option #4 improves return time by a day, 24 hours. But the SM jettison
introduces new failure potential. Recommendation—NO.
Option # 5 improves return also but requires a power up and likely
depletion of the CSM entry batteries which may or may not be rechargeable.
Also requires using the SPS engine where the problem started. Recommendation—NO.
recommendation was Option #2. Deke Slayton had a question about one
of the faster return options. I answered. Gerry and I were still bracing
for a prolonged discussion. The senior NASA official was Dr. Thomas
Paine, the NASA Administrator. He did not know us but, of course, George
Low, his deputy, did. After the one question from Deke, Dr. Paine took
over and thanked me for the discussion and the clarity of the situation
report and then he said, “I only have one question. What can we
do to help you men?” WOW. Gerry and I looked at each other and
I replied that we believe that we have all the needed support in place,
but, “Thank you for the offer. We will certainly ask if we ID
The meeting was over. The Administrator was satisfied and offered his
full support. It was only later that I had time to reflect on that simple
exchange and what it displayed about how NASA operated in those days.
Also, I can only assume that George Low “sold” the MCC team
to his boss, probably on the airplane ride to Houston. It was an empowering
conclusion to what could have been a much tougher meeting. I have thought
about it often in later years and marvel at the delegation of trust
which Dr. Paine bestowed on our team. Quite a man. Quite a leader. And
that was the way NASA operated in those times.
About 70 hours GET ( 14 hours since problem start)
The RETURN HOME Step # 4 (final) plan was confirmed with the same plan
which we preliminarily sent to the crew at 63:05 GET (7:10 since problem
start). We still had the CO2 fix and the entry procedures to solve.
Plus, a raft of non-standard operations and procedures for the spacecraft,
crew and mission still needed near continuous attention. The team was
in full-court press mode.
Outside the MCC floor, the engineering talents of every involved organization
and company were fully engaged, from the prime contractors—North
American Rockwell and Grumman—to the flight software at MIT, the
space suit builders, and to the laboratories and simulators across the
country. Most of the crews assigned to upcoming flights, plus Ken Mattingly,
were verifying procedures, duplicating the planned propulsion burns
and the entry scenarios in the simulators and trainers. Another recovery
ship was being added for the mid-Pacific landing site. And when people
showed up and were un-busy, they would always get coffee for others.
This was “whatever-it-takes-time.”
Outside the team, we gradually became aware of the outpouring of concern,
support, and prayers from fellow humans across the globe. It seemed
to grow in intensity and scale all the way through landing and recovery.
As the time for the PC+2 maneuver approached, Gene and his White Team
went through a review of the mission rules for the burn and the attendant
variations. The burn went just fine, the power down started to about
12 amps, equivalent to three 100 watt light bulbs. Apollo 13 was on
the way home. After this shift, Gene took the entry team offline and
continued the work of detailing the CSM and LM plans for the end of
90:09 GET ( 34 hours:14minutes after the start of the problem)
Joe Kerwin, the capcom who followed it the whole time, began to read
up the procedure for using the CSM LIOH canisters to scrub the CO2 out
of the LM cabin. Once implemented, the CO2 readings dropped from 7.5
mm Hg to 0.7mm in short order. The RETURN HOME Step #5 worked fine,
full credit to the Crew Systems Division guys.
A later 7 fps midcourse correction was performed at 105:18 GET. The
LM consumable status at 107 GET continued to improve to the point that
the required consumables would have been supportable by the lesser LM
Ascent stage—only supplies augmented by the PLSS (primary life
support system backpack) O2 and H2Oas supplements.
The MCC pipeline was regularly delivering a number of new and non-standard
checklists for required activities. There were some very effective leaders
of specific areas and probably hundreds of operations and engineering
personnel evaluating all options and astronaut crews testing each procedure
in the simulators.
Soon after the explosion and the CSM was powered down, Gene had gathered
up most of his team offline in one of the staff support rooms and started
to assess the situation. Very quickly, John Aaron announced that we
did not have enough CSM power onboard. Gene then put John in charge
of approving all power usage for the entry phase. John took the challenge
and did not go back to front room console duty until time for the entry
phase. John was always effective at laying out a concept and power profile
as a starting point and then engaging a wider group of experts to buy-in
and refine the concept into a workable checklist. In this case, a back
room expert named Jim Kelly was the key critical help to John in getting
the solution ready for wider participation. A well analyzed timeline
was a prerequisite for the detailing of a checklist of involving circuit
breakers and switches. In the hours before PC+2, the LM team did not
want to commit any power to the CSM. Nevertheless, John still saw his
work as having two options—one without a LM recharge of the CSM
batteries and one with the recharge.
As a result of PC+2, the return trip was shortened by 12 hours and the
team had the opportunity to see the LM power down to 12 amps. The support
for a recharge improved. The team first had to devise an entirely new
procedure for charging the CSM batteries. Jim Kelly took the lead for
this critical invention, with support from Bill Peters of the LM team,
while John Aaron continued with the entry plan.
The spacecraft design for normal power transfer was from the CSM to
the LM. The new procedure (from the LM to the CSM) had to be ready by
the time when there was sufficient confidence in the LM power situation
to charge the CSM batteries. Also, the solution was complicated by having
to power up a Main DC bus and a Main AC bus, plus its associated inverter
in the CSM and live within the current limits of a 7.5 amp circuit breaker
on the charging line. It also required careful closeout once done. And
it required Jack Swigert to configure the CSM switches and circuit breakers
by flashlight and in the cold. This critical checklist was prepared
almost entirely by Jim Kelly and Bill Peters. All done successfully
and is acknowledged here as RETURN HOME Step #6.
From about 112 GET to 129 GET, LM power was used to bring the half depleted
battery A to full charge and, finally, to top off the other two entry
batteries. This was a small 15 percent increase, but which proved very
helpful in providing John's team with just enough power to ease some
of the earlier difficulties in fitting the desired power-up steps to
the power available, and resulting in a less time-compressed timeline.
(In retrospect, the LM power was managed conservatively and that was
understandable. But we had not been sufficiently sensitive to the crew
condition in the cold, cramped spacecraft and the difficult sleeping
environment. A fully informed assessment would likely have led us to
release more LM power earlier to ease the checklist planning bind and
to warm the cabin. We could have provided some improvement on both those
counts. Even so, the crew never complained and performed heroically.)
Arnie Aldrich was the chief of the CSM Systems branch and, as part of
his responsibilities in SPAN, had been coordinating the approval of
the entry checklist with the program engineering and management teams,
both NASA and industry. Eagerly awaited by all of us, and especially
the crew, Arnie approved the release of the final entry checklist by
125 GET. The checklist was 6 pages and had gone through 6 revisions,
every 12 hours.
John Aaron walked it into the MCC. The read-up was delayed briefly to
get checklist copies in all the right hands and recommenced at 126:15.
With its arrival onboard, RETURN HOME Step #7 was accomplished.
The LM was still cold and the power margins permitted an early power
up at about 132 GET, which warmed up the cabin for the comfort of the
crew. As a measure of our earlier electrical power management efforts,
the LM was able to supply the highest level of electrical power of the
entire mission, about 42 amps, and sustained that level for the last
9 hours of the LM operation. The crew performed a LM guidance alignment
using the new Sun-Moon technique, as developed with the Trench and the
supporting mission planning team. This LM alignment saved time and power
later in the CSM timeline because the LM guidance reference could be
transferred to the CSM quickly and easily.
The last midcourse was at 137:40 GET. It took FIDO Bill Stoval the whole
shift to get the Sun/Earth alignment procedure worked, including involving
all three crew men in the execution of the burn, another team innovation.
Jack Swigert was the timekeeper to start and end the burn, with the
other two crewmen controlling attitude with the hand controller and
the translation controller, a trick never done before.
Jim Lovell's comments on the state of the SM after jettison were sobering:
“And there's one whole side of the spacecraft missing. Right by
the high gain antenna the whole panel is blown out, almost from the
base to the engine...It's really a mess.”
Later in the CSM power up sequence, the crew reported: “Main Bus
A and B up and on.” This report told the MCC and especially the
CSM team that the CSM was back from the earlier explosion and from being
unpowered for almost four cold days. Now it was ready to do its job.
A little later after LM separation, a grateful salute went out: “Farewell,
Aquarius and we thank you.”
Onto the blast furnace of entry and Odyssey had one more surprise for
us. For some reason, the end of blackout extended by about two or so
minutes past the normal time and we stayed that much longer in our respective
“Our Fathers” as an uneasy silence stole the air out of
MCC. Then, “2 drogues” pulling out the 3 beautiful main
chutes, landing in sight of the carrier [USS Iwo Jima] and onboard her
in a fast 45 minutes—the crew of Apollo 13 was safely home.
We all had our reactions to the flight. For me, I felt that the Black
Team shift immediately after the explosion and for the next 14 hours
was the best piece of operations work I ever did or could hope to do.
It posed a continuous demand for the best decisions often without hard
data and mostly on the basis of judgment, in the face of the most severe
in-flight emergency faced thus far in manned space flight. There might
have been a "better" solution, but it still is not apparent
what it would be. Perhaps, we could have been a little quicker at times
but we were consciously deliberate.
During the 87 hours from explosion to recovery, there were likely thousands
of spacecraft configuration and mission timeline choices. There were
numerous new innovations imagined, perfected and made available on-time.
All of these were a vital part of improving the prospect for a safe
and successful outcome.
We built a quarter-million mile space highway, paved by one decision,
one choice, and one innovation
at a time—repeated constantly over almost four days to bring the
crew safely home. This space highway guided the crippled ship back to
planet Earth, where people from all continents were bonded in support
of these three explorers-in-peril. It was an inspiring and emotional
feeling, reminding us once again of our common humanity. I have always
been so very proud to have been part of this Apollo 13 team, delivering
our best when it was really needed.
After the flight there were some extraordinary events that occurred
in rapid succession. President Richard Nixon arrived at JSC to award
the Presidential Medal of Freedom to the entire Mission Operations Team.
The ceremony was held outside on a beautiful Spring day to accommodate
as much participation as possible. Sig Sjoberg received the medal on
behalf of the team. Speeches appropriate to the event resounded across
Next, I was assigned to brief the Senate Aeronautical and Space Sciences
committee with Senators Clinton P. Anderson. chairman, and Margaret
Chase Smith presiding. It was April 24, 1970, just a week after landing.
And a very great honor for me to tell the story of what our team did.
I also had a chance to visit with Bill Anders who was now on Vice President
Spiro Agnew's staff of the new National Space Council. This was the
start of an amazing career for Bill outside of the astronaut role. I
was also invited to the home of Ethel Kennedy and family for a small
party to commemorate the event. It seemed like everyone wanted to celebrate
the successful return of Apollo XIII. Senator Ted Kennedy was there
and he was already into “re-ordering our priorities,” meaning
less money for the space program which had peaked at 4.5 percent of
the federal budget—an understandable reaction even though it was
President John Kennedy's goal of the “end of the decade”
which drove that funding. (NASA never came close to that level again,
more like 0.5 percent in recent times).
I had just got home from that excursion and we—Sig Sjoberg, Apollo
XIII astronauts (except Fred Haise who was still on the mend from an
infection) and flight directors—were on the Gulfstream, headed
for Chicago. What a whirlwind trip that was with a chance to see the
legendary Mayor Richard Daley in action and full command. I had my most
vivid memory of him from the TV coverage of the 1968 Democratic Convention
in Chicago when the protests and the Chicago response filled the streets
of that famous city with a very ugly scene. This was different, and
the machinery of the city purred like the sleek machine that it was.
Former President Lyndon Johnson had just left the city and we saw access
control of the on-off ramps to the main freeway, superbly timed to clear
the path of traffic and then re-open as we passed and to resume normal
flows. We were on a fast dash to meet many city and state officials,
school teachers, and kids. We rushed into a hotel expecting more of
the same, and when we got to a beautiful suite with a grand view of
the city, the mayor announced that we had 30 minutes to catch our breath
and the bar was open, favoring Bloody Marys at this time.
Then we traveled in open convertibles on a parade around the city loop,
waving to a multitude of people with American flags and joyful at what
we had just pulled off. When we did get back to the plane, we found
silver bowls engraved for the occasion for our wives. Pretty classy
operation, Mayor Daley; thanks for a spectacular day.
to Glynn S. Lunney
to JSC Oral History Website