Rocket Men: The Daring Odyssey of Apollo 8 and the Astronauts Who Made Man's First Journey to the Moon(16)

The Earth–Moon crossing would last about sixty-six hours. The astronauts would spend much of that time doing navigation sightings, making live television broadcasts, and checking systems. The spacecraft would fly on a precise round-trip pathway, aimed close enough to the Moon’s surface to ensure that if anything went wrong along the way, the Moon itself would make the rescue, catching the ship with its gravity and slingshotting it back to Earth, all courtesy of the laws of physics, with no man-made propulsion required.

As Apollo 8 neared its target, the Moon would be moving at more than 2,000 miles per hour, with the spacecraft rapidly accelerating, both approaching nearly the same spot in space. If NASA’s figures were accurate, the ship would slide just ahead of the Moon’s leading hemisphere, then use lunar gravity to curl behind the lunar far side.

Once the spacecraft went behind the Moon, all communication with Mission Control would be blocked. At that point, if all looked good, Borman would fire the Service Propulsion System, or SPS, engine, which would slow the ship enough to be captured by the Moon’s gravity and enter lunar orbit. There was no backup to the SPS. If it didn’t fire, Apollo 8 would whip around the Moon and return to Earth. The real problem would come if the engine fired incorrectly: too short or too weak, and the spacecraft would fly off into eternal space; too long or too strong, and it would crash into the Moon in less than an hour.

If it all worked, however, Apollo 8 would enter an irregular orbit, about 69 miles above the lunar surface on the far side and about 200 miles over the near side. For two revolutions (about four hours), the crew would prepare their cameras and observe landmarks. Then they would get ready to fire the SPS engine again, this time to circularize their orbit at a constant 69 miles above the lunar surface. It would then be Christmas Eve morning back in America.

Once in a circular orbit, the crew would do the bulk of its work. For eight revolutions over the next sixteen hours, they would scout candidate landing sites for future missions, take photographs, analyze lighting conditions, and study the effects of gravitational anomalies on the spacecraft’s orbit. All the while, Mission Control would be tracking the spacecraft by radio and communicating with the astronauts, except when Apollo 8 was over the far side of the Moon.

And there would be two more television broadcasts. As Borman did the math, he could see that these would come on Christmas Eve and Christmas Day.

During the final two revolutions, the astronauts would get ready to fire the SPS engine again, this time to gain enough speed to get the spacecraft out of lunar orbit and on its way back to Earth. As before, the firing would be done over the far side of the Moon, out of contact with Houston and the rest of the world. It was another critical maneuver: If it misfired, the ship could crash into the Moon or fly off into the void. If it failed to fire, Apollo 8 would become a possession of the Moon. Forever.

But if all went according to plan, the spacecraft would escape lunar orbit and begin its fifty-seven-hour journey home. In the flight’s last minutes, the service module containing the engine would be jettisoned, leaving the astronauts in the cone-shaped command module they would ride the rest of the way to Earth. A short time later, the capsule would begin reentry into Earth’s atmosphere at near 25,000 miles per hour. No human had ever attempted such a thing, and it had to be virtually perfect or Borman and his crew wouldn’t survive.

Angle of attack was everything. Apollo 8 needed to enter a corridor that spanned just two degrees. That was equivalent to finding exactly the right ridge on a coin that had 180 ridges grooved into it. (By comparison, a United States quarter dollar has 119 ridges.) If the spacecraft came in too shallow, it would skip off the atmosphere like a stone on water, going into a large elliptical trajectory around Earth without enough oxygen or electricity on board to get back for another attempt at reentry. If it came in too steeply, it would grind so hard against the atmosphere that the resulting heat and deceleration would burn up and tear apart the capsule. But if it came in just right, the atmosphere would slow the capsule down enough to allow it to survive reentry into the atmosphere and plunge toward Earth. Two degrees—anything on either side of that and the crew was dead.

If Apollo 8 survived reentry and if its heat shield succeeded in preventing its incineration in temperatures that would reach 5,000 degrees Fahrenheit—half that of the surface of the Sun—the triple canopy of parachutes would deploy and the capsule would splash down in the Pacific Ocean about forty-five minutes before first light. The astronauts would stay inside until a Navy recovery crew reached them. By that time, Apollo 8’s historic voyage would have ended, after a little more than six days.

Borman looked at the other men in the room. Each wore the same expression: We know this is impossible, but we still think it can work. He appreciated their commitment and expertise, but he thought they’d planned too much for the crew to do—every hour seemed loaded with tasks, duties, obligations, checks.

“Forget the TV cameras,” Borman said. “It’s a distraction.”

“No way,” Kraft said. “This is history, Frank. This belongs to the American people.”

“We’re here to do a job,” Borman said.

“That’s part of the job,” Kraft answered.

Borman saw no yielding in Kraft’s eyes. The cameras would stay.

Borman still objected that the work plan was too crowded, and Kraft didn’t deny it. There was a lot to do, maybe too much, but six days on a moonshot was an eyeblink, given the risks and expenditures required to get there, so they damn well had to get the most out of it. Anything less and none of them would be doing his job.