Lovell had availed himself of the relief tube countless times before, but only for its intended purpose. Now he would have to improvise. Strugging out of his life vest, he wrestled it down to the urine port, and with some finessing managed to wedge its nozzle into the tube. It was a forced fit but a workable one. Lovell gave the high sign to Borman, Borman nodded back, and while the commander and the LEM pilot went through their pre-lunar checklist, Lovell coaxed his life vest back to its deflated state, patiently correcting the first blunder he had committed in nearly 430 hours in space.
The maneuver, known as lunar orbit insertion, or LOI, was a straight-forward one, but it was fraught with risks. If the engine burned for too short a time, the ship would go into an unpredictable – perhaps uncontrollable – elliptical orbit that would take it high up above the moon when it was over one hemisphere and plunge it down again when it was over the other. If the engine burned too long, the ship would slow too much and drop not just down into lunar orbit but down onto the moon’s surface. Complicating matters, the engine burn would have to take place when the spacecraft was behind the moon, making communication between the ship and the ground impossible. Houston would have to come up with the best burn coordinates it could, feed the data up to the crew, and trust them to carry out the maneuver on their own. The ground controllers knew exactly when the spacecraft should appear from behind the massive lunar shadow if the burn went according to plan, and only if they reacquired Apollo 8’s signal at that time would they know that the LOI had worked as planned.
It was at the 2-day, 20-hour, and 4-minute mark in the flight – when the spacecraft was just a few thousand miles from the moon and more than 200,000 miles from home – that Capcom Jerry Carr radioed the news to the crew that they were cleared to roll the dice and attempt their LOI. On the East Coast it was just before four in the morning on Christmas Eve, in Houston it was nearly three, and in most homes in the Western Hemisphere even the fiercest lunar-philes were fast asleep.
“Apollo 8, this is Houston,” Carr said. “At 68:04 you are go for LOI.”
“OK,” Borman answered evenly. “Apollo 8 is go.”
“You are riding the best one we can find around,” Carr said, trying to sound encouraging.
“Say again?” Borman said, confused.
“You are riding the best bird we can find,” Carr repeated.
“Roger,” Borman said. “It’s a good one.”
Carr read the engine burn data up to the spacecraft and Lovell, as navigator, tap-tapped the information into the onboard computer. About half an hour remained before the spacecraft would slip into radio blackout behind the moon, and, as always at times like these, NASA chose to let the minutes pass largely in unmomentous silence. The astronauts, well drilled in the procedures that preceded any engine burn, wordlessly slid into their couches and buckled themselves in place. Of course, if anything went wrong in a Lunar Orbit Insertion, the disaster would go well beyond the poor protection a canvas seat belt could provide. Nevertheless, the mission protocol called for the crew to wear restraints, and restraints were what they would wear.
“Apollo 8, Houston,” Carr signalled up after a long pause.
“We have got our lunar map up and ready to go.”
“Roger,” Borman answered.
“Apollo 8,” Carr said a bit later, “your fuel is holding steady.”
“Roger,” Lovell said.
“Apollo 8, we have you at 9 minutes and 30 seconds till loss of signal.”
“Roger.”
Carr next called up five minutes until loss of signal, then two minutes, then one minute, then, at last, ten seconds. At precisely the instant the flight planners had calculated months before, the spacecraft began to arc behind the moon, and the voices of Capcom and crew began to fracture into crackles in one another’s ears.
“Safe journey, guys,” Carr shouted up, fighting to be heard through the disintegrating communications.
“Thanks a lot, troops,” Anders called back.
“We’ll see you on the other side,” Lovell said.
“You’re go all the way,” Carr said.
And the line went dead.
In the surreal silence, the crew looked at one another. Lovell knew that he should be feeling something, well, profound – but there seemed to be little to feel profound about. Sure, the computers, the Capcom, the hush in his headset all told him that he was moving behind the back of the moon, but to most of his senses, there was nothing to indicate that this monumental event was taking place. He had been weightless moments ago and he was still weightless now; there had been blackness outside his window moments ago and there was blackness now. So the moon was down there somewhere? Well, he’d take it as an article of faith.
Borman turned to his right to consult his crew. “So? Are we go for this thing?”
Lovell and Anders gave their instruments one more practiced perusal.
“We’re go as far as I’m concerned,” Lovell said to Borman.
“Go on this side,” Anders agreed.
From his middle couch, Lovell typed the last instructions into the computer. About five seconds before the scheduled firing time a display screen flashed a small, blinking “99:40.” This cryptic number was one of the spacecraft’s final hedges against pilot error. It was the computer’s “are you sure?” code, its “last chance” code, its “make-certain-you-know-what-you’re-doing-because-you’re-about-to-go-for-a-hell-of-a-ride” code. Beneath the flashing numbers was a small button marked “Proceed.” Lovell stared at the 99:40, then at the Proceed button, then back at the 99:40, then back at the Proceed. Then, just before the five seconds had melted away, he covered the button with his index finger and pressed.
For an instant the astronauts noticed nothing; then all at once they felt and heard a rumble at their backs. A few feet behind them, in giant tanks tucked into the rear of the spacecraft, valves opened and fluid began flowing, and from two nozzles two different fuel ingredients swirled together in a combustion chamber. The ingredients – a hydrazine, dimethylhydrazine mixture, and nitrogen tetroxide – were known as hypergolics, and what made hypergolics special was their tendency to detonate in each other’s presence. Unlike gasoline or diesel fuel or liquid hydrogen, all of which need a spark to release the energy stored in their molecular bonds, hypergolics get their kick from the catalytically contentious relationship they have with one another. Stir two hypergolics together and they will begin tangling chemically, like game-cocks in a cage; keep them together long enough, and confine their interaction well enough, and they will start releasing prodigious amounts of energy.
At Lovell’s, Anders’s, and Borman’s backs, such an explosive interplay was now taking place. As the chemicals flashed to life inside the combustion chamber, a searing exhaust flew from the engine bell at the rear of the ship; ever so subtly the spacecraft began to slow. Borman, Lovell and Anders felt themselves being pressed backward in their couches. The zero g that had become so comfortable was now a fraction of one G, and the astronauts’ body weight rose from nothing to a handful of pounds. Lovell looked at Borman and flashed a thumbs up; Borman smiled tightly. For four and a half minutes the engine burned, then the fire in its innards shut down.
Lovell glanced at his instrument panel. His eyes sought the readout that was labeled “Delta V.” The “V” stood for velocity, “Delta” meant change, and together they would reveal how much the speed of the ship had slowed as a result of the chemical brake the hypergolics had applied. Lovell found the number and wanted to pump a fist in the air – 2,800! Perfect! 2,800 feet per second was something less than a screeching halt when you were zipping along at 7,500, but it was exactly the amount you’d need to subtract if you wanted to quit your circumlunar trajectory and surrender yourself to the gravity of the moon.
Next to the Delta V was another readout, one that only moments before had been blank. Now it displayed two numbers, 60.5 and 169.1. These were pericynthion and apocynthion readings – or closest and farthest approaches to the moon. Any old body whizzing past the moon could get a pericynthion number, but the only way you could get pericynthion and apocynthion was when you weren’t just flying by but actually circling the lunar globe. Frank Borman, Jim Lovell, and Bill Anders, the numbers indicated, were now lunar satellites, orbiting the moon in an egg-shaped trajectory that took them 169.1 miles high by 60.5 miles low.
“We did it!” Lovell was exultant.
