Apollo’s final warm-up act
Two months before lunar landing, mission showed it could be done
By the spring of 1969, the reasons for John F. Kennedy’s improbable challenge to put a man on the moon no longer seemed to apply — at least not with the urgency that spurred him.
The heat of the Cold War had lessened. The U.S. no longer felt the sting of its rockets blowing up on the launch pad. And new priorities were claiming center stage.
But here we were nonetheless. Congress had responded. The money had appeared. Space flight was now a thing, and in a big way. As mid-May arrived on Florida’s east coast, a nation was beginning to hold its breath.
Kennedy had called for the deed to be done by the end of the decade. Whatever the merits of spending billions of dollars on such a dangerous enterprise, it was going to happen, so long as the flight of Apollo 10 came off without a game-changing hitch. He didn’t live to see it come to pass, but as legacies go, it wasn’t such a bad one.
Ten years earlier, not so many people knew about NASA. It was a small agency that served a variety of purposes. The Soviet Union changed that. In the late 1950s, it set out on a space program of its own, sending up satellites, animals, and eventually humans — all intended to show its technological superiority.
America’s response turned NASA and its astronauts into household names. While the Soviet moon program churned on in relative secrecy — no one knew its exact status — Mercury, Gemini, and Apollo played out live on television. Each flight inched the effort forward, some through technical achievement, some in mastery of method.
It fell to three space veterans to take the final preliminary step aboard a fully loaded Saturn V rocket, the roaring flames of which filled the Cape Kennedy skies during the lunch hour on May 18. To be precise, the launch stack wasn’t quite fully loaded. A tank connected to the ascent engine on the lunar lander was only half-full of gas.
This was not an oversight. The propellant tank was about 2,500 pounds light so that the crew would not be tempted to go ahead and land. Tom Stafford, John Young, and Gene Cernan were confident, experienced members of the astronaut corps, with multiple flights between them. It was not unreasonable to consider that their “right stuff ” impulses might take over. So NASA made sure that doing so would be tantamount to suicide.
“A lot of people thought about the kind of people we were,” Cernan recounted in “Rocket Men,” Craig Nelson’s book on the moon missions. “So the ascent module, the part we lifted off the lunar surface with, was short-fueled. Had we ... tried to land on the moon, we couldn’t have gotten off.”
As frustrating as this may have been, the instructions were clear: Take Snoopy (the name chosen for the Lunar Module) down to 8.4 nautical miles, jettison the lower part of the lander, then fire the ascent engine to return to the Command/Service Module, which had been dubbed Charlie Brown. Those few miles were the only difference between Apollo 10 and Apollo 11.
Of course, for those involved as well as the millions of people following the mission, that short stretch was everything. Like Columbus in 1492, it was setting foot on a new world — not merely seeing it — that opened up humanity’s next frontier.
Not that there weren’t some within NASA officialdom who felt that Apollo 10 should have been tabbed to attempt the moon landing. The two previous flights had demonstrated the apparent worthiness of the equipment and the approach. Why wait?
Ultimately, the agency chose caution: Do everything that the “real” moon shot would do except drop those final eight miles. Make sure nothing unexpected arose.
As it happened, something did. A few moments before separation between the lander’s upper section and the lower, which in the event of an actual landing would stay on the lunar surface, the ascent stage began to pitch and yaw.
“Son of a bitch!” Cernan shouted. “What the hell happened?”
The shocked pilot, Stafford, was caught equally off guard. “We’re in trouble,” he said. Back at Mission Control, Tom Kelly, the Grumman engineer whose team had built the longtroubled lunar module, heard the comments and heavy breathing over the live mic. Suddenly, his attention was riveted on what he later described as as Snoopy “throwing a fit.”
Over and over the little craft tumbled. Five revolutions ... six ... seven. Stafford took over manual control, fighting to stabilize it in an unfamiliar environment. Nobody was quite sure how long it took him to settle things down, perhaps 10 seconds. As Snoopy gradually yielded to his inputs, he jettisoned its lower section
Later it was determined that an improperly flipped switch had taken the ship out of the abort landing sequence and forced its radar to look for the CSM, which was not anywhere close. The astronauts had created the problem, but had quickly solved it, averting a disaster that could have brought the Apollo program to a temporary halt.
The unsettling episode with Snoopy had lasted about three minutes, Kelly later remembered, but otherwise his oddlooking tiny spaceship had performed perfectly. The ascent back to lunar orbit and reunion with good ol’ Charlie Brown brought no more excitement.
NASA chose to downplay the incident. That the lander was perhaps a few more rolls from becoming unrecoverable, and ultimately a wreck on the surface of the moon, did not diminish the agency’s faith in it. Or Kelly’s.
“Recalling all the years of work, failures, and frustrations, it was hard to believe that our dogged, fumbling efforts were close to achieving their goal,” Kelly said in his memoir about building the lander. “In three spaceflights our LM had performed better than I believed possible — nothing like the problem-ridden ground tests.”
Besides one more chance to confirm the reliability of the Lunar Module, the mission gave NASA better understanding of the moon’s gravitational field, which in turn allowed for better calibration of the descent guidance system. The crew also offered television viewers another glimpse inside the spacecraft, this time with a color camera. Only the moon itself was still stuck in a black-andwhite era.
Apollo 10 spent eight days on the journey to and from the moon. Except for the minutes of sudden terror, when the lunar craft appeared to go haywire, the mission was uneventful. A shaky launch that produced more of the unwanted pogo oscillations failed to cause injury to Snoopy, which for the second straight flight met all expectations.
There was no need for more testing. As primitive as some of the technology would seem 50 years on, it was as good as it was going to get at the time.
More important, it was as good as it needed to be to realize a dream few thought possible just a few years earlier, when a young president showed up in Houston on a hot summer day and challenged his nation to think bigger.
“A lot of people thought about the kind of people we were. So the ascent module, the part we lifted off the lunar surface with, was short-fueled. Had we ... tried to land on the moon, we couldn’t have gotten off.”
— Gene Cernan, Apollo 10 astronaut