The Mammoth Book of Space Exploration and Disasters

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.

“Right down the pike,” Anders said.

“Orbit attained,” Borman agreed. “Now let’s hope it fires tomorrow to take us home again.” Achieving orbit around the moon, like disappearing behind it minutes earlier, was a bit of an academic experience for the astronauts. Once the engine had quit firing and the crew had become weightless again, there was nothing beyond the data on their dashboard to confirm what they had achieved. The moon was just five dozen miles below them, but the spacecraft’s upward-facing windows had not permitted the astronauts a look. Borman, Lovell, and Anders were three men who had backed into a picture gallery and had not yet turned around to see what was inside. Now, however, they had the luxury – and, with reaquisition of ground contact still twenty-five minutes away, the undisturbed privacy – to conduct their first survey of the body whose gravity was holding them fast.

Borman grabbed the attitude control handle to the right of his seat and vented a breath of propellant from the thrusters arrayed around the outside of the spacecraft. The ship glided into motion, rolling slowly counter clockwise. The first 90 degrees of the roll tipped the weightless astronauts onto their sides, with Borman at the bottom, Lovell in the middle, and Anders at the top of the stack; the next 90 moved them upside down, so the moon that had been below them was all at once above. It was into Borman’s left-hand window that the pale gray, plastery surface of the land below first rolled, and so it was Borman whose eyes widened first. Lovell’s center window was filled next, and finally Anders’s. The two crewmen responded with the same gape the commander had.

“Magnificent,” someone whispered. It might have been Borman; it might have been Lovell; it might have been Anders.

“Stupendous,” someone answered.