CRITICAL FLIGHT NOTES AND UPDATES BY LOVELL AND HAISE MADE DURING APOLLO 13.
Flown on Apollo 13, LM Contingency Checklist, pp PWR-5 and PWR-6. A single sheet printed recto and verso, 8 by 5½ inches with a tab reading: "EMER PWR DN" on both sides. Fifteen MISSION ANNOTATIONS in red ink by James Lovell and eleven in black ink by Fred Haise.
Some 55 hours into the Apollo 13 mission, the crew was completing a television transmission to Mission Control describing the interior of Lunar Module Aquarius and the equipment that would be used during the third lunar landing mission. At 55 hours and 53 minutes, Mission Control asked the crew to activate a switch to stir their fuel cell oxygen tanks. Unbeknownst to them at that time, that procedure caused an electrical short circuit within oxygen tank number 2. The resulting electrical arc heated the oxygen in the tank increasing pressure to a point where the tank exploded. Within seconds the crew heard a large bang, then warning lights flashed on the instrument panel.
The crew and Mission Control began a series of trouble shooting steps trying to isolate the problem. But as each minute passed, power and life-giving oxygen disappeared from the Command / Service Module (CSM). The crew was forced into an emergency activation of Aquarius as the only means to survive.
In order to reach their planned landing site, Fra Mauro, the crew made a course correction burn at the 30 hour point in their mission. That changed their trajectory from the fail-safe "free return trajectory" used during earlier Apollo missions. The "free return" allowed the CSM/LM to swing around the moon and return directly to the earth if they were unable to achieve a lunar orbit using the CSM's large rocket engine. The Apollo 13 crew immediately shut down the CSM systems and rapidly activated the LM systems to serve as a "life boat" during the emergency. Some 5½ hours after the explosion, James Lovell and Fred Haise performed a 30 second LM Descent Propulsion System (DPS) engine burn to place them back on a free return trajectory.
That burn got them in a position to return to the Earth, but the task would be futile if they ran out of oxygen and battery power during the four days required to make a splashdown in the Pacific Ocean. Mission Control radioed changes to the Emergency Power Down procedures listed on PWR-5 and PWR-6 in order to conserve sufficient power to survive the return journey to Earth.
An accompanying letter of provenance by FRED HAISE reads in part: "We had experienced an extremely busy time after the explosion an LM engine burn to put us back on a path home, then our pass behind the moon, and finally another LM engine burn of over 4 minutes to get us back to earth on April 17.
At about 79 hour point of our flight, Mission Control radioed the changes I logged under the EMERGENCY POWER DOWN section of page PWR-5. I crossed out the 'And VHF A, Simplex Operation' on the first two lines. I then deleted the second 'PRIM' (meaning Prime Power Amp) and wrote 'OFF' just above it. I later marked out that update. The last change on that line was 'OFF' to 'PCM' (meaning Pulse Code Modulation). My last change to that side was deleting all of step 2. After the mission I wrote at the bottom of that side: 'In flight notes by LM crew Carried and used during the flight of Apollo 13. Fred Haise, Apollo 13 LMP.'
The side numbered PWR-6 has extensive changes made by myself and James Lovell. We needed to open or close various circuit breakers on Panel 11 to use those systems when required, then conserve battery power when completed. Mission Control had me close 4 breakers of the RCS A (Reaction Control System A). I marked it with 'CLOSE,' made a long line, then wrote 'CLOSE' again. I wrote 'CLOSE' under one breaker at the third row, then same for the last three breakers on the fourth row during the initial series of updates. I also wrote the 'OPEN' with the 'X' mark on the fifth row.
An additional challenge after these updates was to configure the lithium hydroxide canisters from the Command Module to work in the LM. Carbon dioxide was building up quicker that normal since we had three crewmen in the LM rather than the planned two during a normal mission. We configured a make-shift arrangement based on Mission Control's instructions which solved that problem.
At about 82 hours into the flight, Mission Control sent updates to James Lovell which he made in red ink. I was in the Command Module during a rest period. Jim made corrections to my earlier entries with 'OUT' written five times on the second and third rows. He made two 'CLOSE' and four 'OPEN' changes to row four. At this time we had various issues developing with spacecraft thermal attitudes, antenna viewing angles, and telemetry power expenditures. Mission Control radioed to us a procedure that Jim recorded in two red rectangular boxes along the page edge: 'Turn LM up link squelch off' and 'Earth FWD, Moon AFT.' That was a reminder that when we saw the earth in the LM window, use the forward antenna. If the moon was in the window, we should use the aft antenna. The '3 to 5 min to est. lock' was the time it would take Mission Control to establish a communications lock on either the forward or aft antennas. On this side I wrote after the flight: 'In flight notes by James Lovell Carried on and used during the flight of Apollo 13. Fred Haise, Apollo 13 LMP.' Notes in black by myself Fred Haise.'
This sheet played an important part during the emergency conditions of the Apollo 13 flight. It is a record of the real time steps the NASA and industry team developed for us to perform ensuring our safe return to earth."
Additionally, side PWR-6 has been SIGNED AND INSCRIBED: "James Lovell, Apollo 13 CDR."