Then it was time to abandon the Aquarius and strap into the command module. For the lunar module controllers it was a bittersweet moment. "We were proud of the Aquarius and very thankful—it had really performed, did everything we asked it to do" remembers Legler. "It's hard to describe that feeling," says Hannigan, "thank God that we made it but..."

"Farewell, Aquarius, and we thank you," radioed Lovell back in 1970 as the astronauts jettisoned the lunar module and watched it slowly drift away. Hannigan remembers hearing Lovell's unbidden requiem for the spacecraft. "He did a good job," says Hannigan.

It was about another hour before the command module, headed for the Pacific, met the first tenuous wisps of Earth's atmosphere. Soon, as the Odyssey plunged into the atmosphere, those wisps would become a tremendous fireball of ionized air. The ionization would block radio communications for several minutes. In the meantime, the heat shield would be subjected to incredible temperatures and pressures, and if it had been cracked during the explosion four days earlier, the crew would burn up without ever being heard from again. Assuming the heat shield was okay, then the parachutes would deploy, slowing the Odyssey to a gentle splashdown—if the parachutes hadn't been turned into blocks of ice and the pyrotechnic charges intended to release them still worked. In a few more minutes Lovell, Haise, and Swigert would either be home free, or dead.

But the astronaut's last words before re-entry were not for themselves. They were for mission control. "I know all of us here want to thank all of you guys down there for the very fine job you did," Swigert transmitted. "That's affirm," chimed in Lovell.

A few seconds later, the Odyssey disappeared into a sea of radio static.

By Apollo 13, NASA had a pretty good handle on radio blackouts during re-entry, and for a given trajectory, it could work out how long—almost to the second—a spacecraft would be out of touch. In the Odyssey's case, it was about 3 minutes.

The appointed time came and went, and as the seconds turned into minutes without any sign of the Odyssey, the tension dragged out like a rusty blade through mission control.

"It was the worst time of the whole mission," agrees Kranz. "The blackout was a very difficult time for every controller. You ask yourself 'did I give the crew everything I needed to and was my data right?'...It was just a difficult time."