(Below left) Haise restrained his hands so that his arms would not flop about in the weightless of space. (Below right) Lovell sleeps in Aquarius.
Heat from repeated firing of the descent engine had caused an increased rate of pressure buildup in the LM's supercold helium used to pressurize the fuel tanks but no longer needed. Just after noon the tank's burst disc--a relief valve--ruptured, as it was designed to do, and the helium vented into space. The gas had been expected to spew out equally in opposite directions, having no propulsive effect on the spacecraft. CAPCOM--See anything?
SC--Yeah, I was just about ready to call you. Underneath Quad 4, I noticed a lot of sparklies going out.
CAPCOM--Can you hear or feel anything?
SC--I sure did... I think it changed our PTC (Passive Thermal Control of the spacecraft by slowly rotating it to distribute the Sun's heat) ... I was in right yaw and now I'm in left yaw, at a much faster rate... Is that what they call a non-propulslve vent?
CAPCOM--Right. I'd hate to see a propulsive one.
Thermal control was soon restored by use of bursts from the control thrusters until the slow rate of rotation was readjusted. Switches were thrown to begin recharging the Command Module's reentry batteries from the LM's. And the astronauts of Apollo 13 were allowed the first period of relatively relaxed activity since the accident. But their physical hardships grew by the hour.
Temperatures in the darkened CM dropped to 38 degrees. Lovell and Haise pulled on their lunar boots, Swigert an extra suit of long underwear. The cabin walls were perspiring, the windows wet and partly frosted over. All food was cold, for there was no hot water in the LM to mix with the dehydrated meals. The men dozed, always leaving one on watch, but real sleep was rare. Deke Slayton, chief astronaut as Director of Flight Crew Operations, told them they could take stay-awake pills during the final hours.
At Mission Control, Gene Kranz's entire team of flight controllers was taken off its regular shifts to work out and rehearse spacecraft separation and entry routines. Astronauts in the simulators proved out every maneuver and crew procedure. Thursday evening Capsule Communicators began hours of reading up check lists to Swigert, then Haise.
SC--I may not sound too clear, because I'm holding a flashlight between my teeth.
Shortly before 4 o'clock Friday morning, Eastern Standard Time, Lovell and Haise, unable to sleep longer, began powering up Aquarius three hours earlier than planned. The cabin warmed a bit. As they realigned the guidance system, Swigert--watching the time till he could begin reviving dead, cold Odyssey--wryly urged them on:
SC--That Earth is whistling in like a freight train.