Just before 11 p.m. on July 20, 1969, NASA astronauts Neil Armstrong and Buzz Aldrin descended the Eagle lunar module’s nine ladder rungs, impressing their boot prints on the moon’s dusty surface and cementing their achievement in the annals of history.

Marveling at the achievement, we often forget an important detail: the Apollo 11 mission was merely at its midpoint. The two astronauts stood 240,000 miles from home, 60 miles beneath their orbiting colleague, Michael Collins, and one big test of physics away from punching their ticket to safety.  

Twenty-five hours after Armstrong made “one giant leap for mankind,” a marvel of relative velocity delivered a gargantuan “I told you so” from former NASA engineer John Houbolt.

The Eagle lifted off from the moon’s surface at 1:54 p.m. on July 21 and guzzled nearly 5,000 pounds of fuel as it closed on Collins in the command module Columbia at 120 feet per second. At a gap of 25 feet, the two crafts held steady, engaging in a careful dance. Collins inched Columbia forward, needing two attempts to catch 12 latches and pull the two vehicles into a docking position. At 5:35 p.m., the three astronauts reunited.

“We’d like to congratulate everybody on a successful rendezvous,” capsule communicator Charlie Duke said.

There was gravity in this moment. It was a triumph—and the beginning of a safe journey home—at the critical juncture of lunar orbit rendezvous (LOR).

The procedure earned NASA’s blessing as the Apollo 11 mission mode seven years earlier, but only after a tremendous fight. As former AU Board of Trustees member Bill Causey, SPA/BA ’71, details in his 2020 book, John Houbolt: The Unsung Hero of the Apollo Moon Landings, the moment would not have been possible without the persistence of a midlevel engineer at Langley Research Center in Hampton, Virginia, who risked his career and reputation by defending LOR to the moon and back.

The maneuver was the live performance of a process that captivated John Houbolt 10 years earlier when, in 1959, an ad hoc group of engineers at Langley gathered to kick around ideas about orbital mechanics and spaceflight. One was rendezvous, and as he dove deeper, Houbolt, a 17-year veteran and head of its theoretical mechanics division, believed it could cut down on time and fuel consumption, thus playing an important role in NASA’s future.

He wanted others to believe it, too, and asked Langley’s models division create a mockup—composed of a globe, a miniature ball fixed to a wire coat hanger, and a battery-powered motor—to demonstrate how changing the orbital plane of a target satellite could impact the launch window of the trailing spacecraft. The Iowa native often lugged the contraption with him when he explained rendezvous.

LOR clicked as a moon landing method for Houbolt as he reviewed the back-of-the-envelope calculations of a fellow engineer, Bill Michael. By keeping one fuel-carrying component in orbit and using a smaller lander to reach and depart the moon’s surface, NASA could dodge the size, weight, and fuel capacity issues that complicated more direct landing approaches.

“The thought struck my mind, ‘This is fantastic. If there is any idea we have to push, it is this one!’” Houbolt, who became the de facto LOR expert within NASA, later wrote. “I vowed to dedicate myself to the task.”

As NASA officals began discussing the moon landing in 1959 and 1960, it was clear that they did not share Houbolt’s vision. Many favored methods they naively believed were safer and more straightforward, including direct ascent—landing and returning in a big spacecraft—and later Earth orbit rendezvous (EOR), which entailed firing several rockets and assembling vehicles in low orbit before blasting moonward. That, too, required a bigger landing vessel.

Wernher von Braun—the rocket scientist for Nazi Germany who later became director of the Marshall Space Flight Center and an EOR proponent—questioned the idea of attempting a first rendezvous 240,000 miles away. If the plan failed, he argued, there was no safety valve for astronauts.

Others were more direct—and personal—with their dismissals. As Houbolt explained LOR’s weight advantages to managers in late 1960, Maxime Faget, an engineer who designed several key NASA spacecrafts during his 35-year career, stood and shouted, “His figures lie! He doesn’t know what he’s talking about.” Charles Donlan of the Space Task Group similarly told Houbolt in July 1961 that he could “throw out all that nonsense.”

In fall 1961, sensing LOR was an option of last resort for many, Houbolt grew bold—and began writing. He drafted a two-volume technical report on LOR and distributed it widely and, in a breach of protocol, drafted a nine-page letter to NASA deputy administrator Robert Seamans.

“It is conceivable that after reading this you may feel that you are dealing with a crank,” Houbolt wrote. But he nonetheless cranked out his arguments: that LOR hadn’t been given a fair shake and that endless uninformed committees had overcomplicated the mode debate.

“It is therefore important that we move in the right direction now,” Houbolt argued in a note stapled to the front of the envelope. “Already too much time has been wasted.”

Houbolt’s letter irked Seamans, who later said, “It seemed like I maybe ought to throw it in the wastebasket.” It did, however, get NASA higher-ups talking, and Seamans gave Houbolt credit—“for being a burr in my side.”

The wake-up call coincided with a series breaks in LOR’s favor.

That same winter, as Faget struggled to design a lunar lander, he returned in his doodles to a smaller vehicle able to deftly navigate the final moments of descent onto a dusty surface—a perfect fit with LOR. Joseph Shea, deputy director of the manned space flight office, arrived at NASA in January 1962 with an open mind. And NASA was forced to think creatively about a “best” method amid several critical deadlines: May for a mode decision and the end of the ’60s for a moon landing. It was also only a matter of time before the Soviets achieved their latest triumph in a space race with more than scientific bragging rights on the line.

“The nation that won the Cold War was going to be the nation with the bigger missiles, and the last thing that anybody wanted to do was fire them at their enemies as a way of demonstrating that,” says School of Public Affairs professor Howard McCurdy, who studies space policy. “Project Apollo became a surrogate for what was otherwise unthinkable.’”

By summer 1962, what appeared unthinkable just a year before slid firmly into place. Finally convinced of its feasibility, NASA officials fell in line behind LOR. After a surprise speech supporting it in June, Von Braun, one NASA’s last major holdouts, sent Houbolt a letter thanking him for his “interesting” two-volume report.

With the internal debate settled, NASA held a press conference in July announcing the LOR method decision. NASA chief James Webb referred to Houbolt by name and lauded Langley’s research, but the glory stopped there.

Writes Causey, “Nobody in the press corps asked who John Houbolt was.”

Growing up in Baltimore, Causey, like many Baby Boomers, was fascinated by what lay unexplored beyond Earth’s atmosphere.

As a sixth grader in 1961, he sat in his middle school gymnasium, eyes glued to a black and white TV, as Alan Shepard rode Freedom 116 miles into suborbital flight. Home with the flu in 1962, Causey devoured Don Myrus’s The Astronauts, memorizing the locations of dials and gauges in a picture of the Mercury capsule.

In high school, he occasionally played hooky, catching the train to Washington to roam the halls of NASA headquarters. “I don’t think my parents ever found out about it,” he says. One day in 1965, he snuck into a press conference for the Gemini 4 astronauts, a moment the 16-year National Air and Space Museum docent remembers each time he passes the mission’s on-exhibit capsule.

But even to Causey, much of Houbolt’s story was unknown. In 1989, he stumbled upon a footnote in Charles Murray and Catherine Bly Cox’s Apollo: The Race to the Moon mentioning that “there is a fascinating doctoral dissertation yet to be written on this [mode selection] episode.” Causey’s interest grew in 1995 when Auburn University professor James Hansen penned a history of Langley, Spaceflight Revolution, with a chapter on Houbolt entitled “Enchanted Rendezvous.”

Causey finally gave in to his curiosity in summer 2005 when the attorney traveled to Houbolt’s alma mater, the University of Illinois, to read his collection of papers. Causey spent three days diving into the engineer’s reports and black-and-white marbled composition notebooks filled with meticulous block letters scribed in mechanical pencil.

When he returned home to Washington, Causey tracked down Houbolt’s Scarborough, Maine, address through a friend at NASA and scratched out a letter:

. . . I’ve read a little bit about you, and I’ve been out to read your papers at Illinois, and I’d love to interview you. If you’re interested, here’s my phone number—please give me a call.

Causey thought that even if the note reached Houbolt’s orbit, it would be ignored; after all, he wasn’t a science writer, and Houbolt probably received many similar requests. Nevertheless, he returned home one evening to a voicemail: “Mr. Causey, this is John Houbolt. I got your letter and I’d be happy to meet with you.”

Causey and his wife, Sally, boarded a plane to Maine a week later. A book project prepared for takeoff.

Houbolt’s was one in a constellation of space-race contributions, and history is such that singular moments—launches and landings—often eclipse the efforts that precipitate them.

The star behind LOR only occasionally shined.

Houbolt claimed one of just 76 seats in the visitor center overlooking Mission Control on July 20, 1969. He earned thanks from Von Braun in that room moments after Eagle landed; from Aldrin two months later with an American flag the astronaut had carried to the moon and back; and from NASA, which awarded him $15,000 for his scientific and technical contributions in 1982.

To Houbolt, the recognition felt tardy and hollow. Over nine years, countless phone calls, and four in-person visits with Houbolt—including a final trip to Maine just months before Houbolt’s death in April 2014—Causey slowly began to “pry that cover open” and reveal behind Houbolt’s midwestern nice a bitterness over how he had been treated by NASA.

Houbolt left NASA in 1963 for a job with Aeronautical Research Associates of Princeton, Inc. It brought with it a pay bump; more time with his wife, Mary, and three daughters; and some needed distance from the organization he had helped thrust 240,000 miles skyward.

“Maybe he was a little anxious and premature to think he was going to get a lot of recognition in 1962, but he thought he should have gotten more credit,” Causey says of Houbolt, who later returned to NASA as Langley’s chief aeronautical scientist from 1976 until his retirement in 1985. “Although he never said to me that [leaving] was the wrong decision, I think he soon regretted that he left NASA as early as he did, but John had a lot of scars from this battle.”

After Houbolt’s passing, the work to launch his story continued. Causey retired—for a second time—at the end of 2016, and finally had the bandwidth to write. He also had a valuable resource in Mary, a whip-smart former Langley human computer whose memories helped Causey flesh out pages of detail.

The book published last March—but it wasn’t the only Houbolt artifact pushed into the world in 2020. Later in the year, Causey helped Houbolt’s family donate his globe gadget to Air and Space. It’s expected to go on exhibit at the Steven F. Udvar-Hazy Center in Chantilly, Virginia, later this year.

As part of a COVID-disrupted book tour, Causey in November joined a Zoom call with 300 engineers on NASA’s Artemis project, which aims to land the first woman and the next man on the moon this decade.

“You could almost hear the jaws hitting the table” as he waded into the divisions that nearly derailed the moon landing and described Houbolt’s belief in LOR, the glue that held the fractured pieces together.

“Without a John Houbolt who kept poking his nose into the middle of all of these meetings and kept pushing this idea,” Causey says, “we never would’ve figured this out in time.”