Historians have an unromantic term for describing what the rest of us would call a series of lucky coincidences. These moments when an idea takes root amid just the right people, when a decision is made with fortunate foresight, when some rocket enthusiasts find just the right spot outside of town to test their novel inventions–these are the “contingencies” in history. “And the development of anything like this is a very contingent process,” says Erik Conway, who has the enviable job as the historian at the Jet Propulsion Laboratory in Pasadena, California. “It’s contingent not just on things that go well but on things that don’t.”

Pasadena, a quaint city of 138,000 about 10 miles northeast of L.A., has long been synonymous with the lab, which the California Institute of Technology manages for NASA. Pasadena and the Jet Propulsion Lab are probably also synonymous in your mind with the Mars Curiosity rover. If you watched any of the deliriously happy YouTube videos of NASA flight controllers cheering Curiosity’s touchdown on August 6, that happened here.

But Conway’s story of how this place came into being–and how Southern California came to be home to many of JPL’s more earth-bound spinoff technologies–is full of those quirky contingencies of weather and land and ideas and people. “If you removed the availability of the land,” Conway says, “or the availability of Caltech’s expertise and the wind tunnel infrastructure it had–any of those things, it might not have happened.”

The Jet Propulsion Lab’s first tests of a rocket engine kinda, sorta worked.

The story begins in the 1930s with a Caltech graduate student named Frank Malina who was studying at the university’s Guggenheim Aeronautical Laboratory under the engineer Theodore von Kármán. In 1936, Malina happened to meet two other young men from outside of the university who were equally intrigued by the relatively new notion of rocket science. Ed Forman was a machinist and John Parsons was, in Conway’s words, “a self-taught explosive wizard.” The three formed a kind of ad-hoc band to begin testing their own rockets.

“But they weren’t allowed to do it on campus,” Conway says. They were sent instead about 7 miles away to the Arroyo Seco on the edge of Pasadena at the foot of the San Gabriel Mountains. The spot, now a sacred site in rocket lore, was near the back end of a mostly empty flood control reservoir. Today JPL dates its origins to Halloween of 1936, when the three attempted the first tests of an alcohol-fueled rocket engine that, Conway says, “kinda, sorta worked.”

The rocket engine experimenters take a break, Nov. 15, 1936

Malina, Forman, and Parsons weren’t the only Americans trying to develop rockets at the time. Physicist Robert Goddard had been at work on the idea in Roswell, New Mexico, where he was infamously secretive about his progress. The Pasadena research, in contrast, was much more transparent. “In a sense, that’s part of their contribution: the recognition that they needed a team,” Conway says. “And so they had to make some concessions to their own potential personal fame. Goddard was a loner, and they just weren’t.”

The lab had become a public face of the space program, so much so that neighboring towns argued over which one could rightly claim to be the parent.

Kármán was a well-connected technical advisor to the Army. And with his own protégés eager for funding, he helped convince the military to finance their rocket projects now underway on the Arroyo. Such rockets, they argued, could enable heavy aircraft to take off from shorter runways. And with World War II on the horizon, this seemed like a useful development. In the early 1940s, the project formally became an Army research lab, under the name–for the first time–of the Jet Propulsion Lab.