Apollo Expeditions to the Moon
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.
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"There's one whole side of that spacecraft missing,"
said Lovell in astonishment. About five hours before
splashdown the service module was jettisoned
in a manner that would permit the astronauts
to assess its condition.
Until then, nobody realized the extent of the damage.
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Vital stores of oxygen, water, propellant, and
power were lost when the side of the service
module blew off. The astronauts quickly moved
into the lunar module which had been provided
with independent supplies of these space
necessities for the landing on the Moon.
Years before, Apollo engineers had talked of
using the lunar module as a lifeboat.
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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."
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Oxygen tank No. 2 overheated and blew up because its
heater switches welded shut during excessive prelaunch
electric currents. Interior diagram (above)
of three-foot-tall oxygen tank No. 2 - whose
placement in bay 4 of SM is
indicated below - shows vertical heater
tube and quantity measurement tube.
Heater tube contains two 1800-rpm
motors to stir tank's 320 pounds of
liquid oxygen. Note thermostat at top.
Two switches were supposed to open
heater circuit when temperature reached 80° F,
but spacecraft power supply had been changed from
28 to 65 Vdc - while contractors and NASA
test teams nodded - so switches welded shut
and heater tube temperature probably reached 1000° F.
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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."
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Top of Apollo 13's fuel tank No. 2 (bottom part is below shelf),
photographed before it left North American
Rockwell plant. Tank was originally installed
in Apollo 10's SM, but was removed for modification and in process
was dropped two inches (skin of tank is only 0.02 inch thick).
Then it was installed on Apollo 13 and certified,
despite test anomalies. In raging heat, it burst
and the explosion was ruinous to the SM.
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Nestled amid crinkled metal foil used for
thermal insulation, oxygen tank No. 2 was
mounted above and close to a
pair of hydrogen tanks in spacecraft bay.
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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.
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