Control Display from Apollo 13
As this week commemorates the 40-year anniversary of the Apollo 13 drama, several interesting mementos from the astronauts’ personal collections came up for auction.
This is one of the goodies that I just won, in this case from the personal collection of Fred Haise, the Apollo 13 Lunar Module Pilot (LMP).
It is the control display that flew around the moon and back on Lunar Module Aquarius, with annotations in red by Fred Haise and signed and inscribed by LMP Haise and Commander James Lovell.
In an accompanying letter, Haise writes:
“I made about a dozen notations in red ink to provide a quick glance reference of details on the LM systems. For instance, I numbered which exact batteries the 'Feed Tie' circuit breakers were tied to – 'Bats 3,4,6' on panel 11 and 'Bats 1,2,5' on panel 16 plus the 'AH' (Amp Hours) available from the Descent Stage and Ascent Stage batteries. These and the other notes turned out to be very useful during our emergency situation during the Apollo 13 flight since all power was being supplied by the Lunar Module after the explosion.”
Not only was power control essential, the LM flight controls had to be used in an entirely new manner. Since the explosion took out the main oxygen tanks, they improvised and used the Lunar Module Descent Engine (LMDE) DPS engine — the engine from the lunar lander, designed to slow the LM’s decent to the moon — to instead push the crippled Command Module and essential Earth reentry capsule in an untested manner, like a rear-engine locomotive.
This 28”-wide page was the only single full-sheet diagram of the Apollo 13 Lunar Module's display and control devices carried on the mission, with over 100 switches, knobs, and meters illustrated.
On approach to the moon, debate ensued on what type of burn to use to get the Apollo 13 lifeboat to loop around the moon and back to Earth. To preserve options and later course corrections, they decided to start with a partial burn to orient the craft in the general direction of an Earth-return path.
“Finally, at 2:43 in the morning [40 years ago, today], Lovell pushed the ignition button and the DPS engine ran at low throttle for thirty seconds, putting the spacecraft into a trajectory that, even without a second burn, would bring it down in the Indian Ocean not quite four days later. Lovell was relieved. He wasn’t completely confident that the burn provided them with a survivable entry [angle], but at least the spacecraft would intercept the Earth’s atmosphere. In his mind, this was much better than the alternative that had just been avoided — orbiting the Earth indefinitely, in a lonely revolution with an apogee of 240,000 miles and a perigee of 3,000 miles, a ‘perpetual monument to the space program.’” (Apollo, p.410)