It took SpaceX four attempts for Falcon 1, a predecessor to the Falcon 9, to reach orbit successfully. The Falcon 1 made a fifth and final flight, successfully, from Omelek Island in the Kwajalein Atoll before the booster was retired. Image credit: SpaceX

Sen—Failures of new rockets used to be common, but that changed with the next-generation of launchers, including SpaceX’s Falcon 9, which flew 18 successful missions before an upper-stage engine problem, still under investigation, caused a mid-air breakup on June 28.

By any measure, SpaceX was, and most likely remains, on a roll, a proverbial bull in the space launch industry china shop that toppled prices, sparked innovation and punched down a behemoth company’s monopoly on the U.S. military’s launch business.

“What’s incredible is the consecutive successes and track record of this rocket. One inevitable failure for such a young system should not shake anyone’s faith in the rocket or the team,” said Mike Gold, business operations director for Bigelow Aerospace, a SpaceX customer.

“Frankly, we congratulate SpaceX and the team to take the rocket to this point,” Gold told Sen.

SpaceX didn’t design Falcon 9 from a blank slate. The company experimented with a smaller Falcon rocket, called Falcon 1, which debuted—with an unwelcome bang—on March 24, 2006. The rocket returned to flight a year later, still flawed.

Another year passed before SpaceX launched again on Aug. 3, 2008, but after the first stage of the rocket separated, it hit the upper-stage dooming the mission. The fourth flight, just six weeks later, proved SpaceX had turned the corner.

“I'd run out of money, and there weren't a lot of people who were keen on funding a rocket company, and I think if we'd said ‘Yes, our fourth launch wasn't successful, but the fifth one's the charm,’ that would not have gone down well,” Musk told the Royal Aeronautical Society in 2012.

SpaceX retired the Falcon 1 after one more flight, also successful, and debuted the first version of its nine-engine Falcon 9 booster in June 2010.

“We took most of the lessons learned from Falcon 1 and we were able to apply that to Falcon 9,” Musk said.

The rocket has not been perfect. One of the Falcon’s nine engines shut down early during launch of the first mission to deliver cargo to the International Space Station, triggering a NASA contract clause that forced SpaceX to skip a restart of the Falcon’s upper-stage, leaving a secondary payload in a lower-than-intended orbit.

“There's an advantage to having the nine engines because if one of them doesn't work and has what we call an RUD—a rapid unscheduled disassembly—then it still makes it to orbit. That's something we think is important,” Musk said.

Preliminary analysis indicates the Falcon 9 launched on Sunday had a problem with the pressurization system in the liquid oxygen tank in the upper-stage engine.

“There are these commonly held rules of thumb that say within the first few launches (of a new rocket) you’ll have a failure related to design and then in the next few launches you’ll have a failure related to operations and then you’ll kind of figure it out and you’ll get on a path where you can have very high reliability,” said Carissa Christensen, managing partner of The Tauri Group, a Virginia-based space and technology consultancy.

“In the last decade, we’ve seen a shift away from that pattern. We’ve seen new vehicles—and the Falcon 9 is an example—that have had very high reliability right up front. That is a tribute in part to better modeling and computational tools and more engineering knowledge and insight about the launch environment. Every time we do a launch we learn things.

“So the cause of the this failure is going to be really important in shaping how people look at our industry, whether they continue to think, ‘Ah yes, our expectations about failures for a new vehicle are fundamentally different than they used to be,' or 'Gosh, this was anomalous and we really should be thinking about the world against that old model,'” Christensen told Sen.

“Eighteen successfully launches is a lot of successful launches and when you take into account the extraordinary complexity of a space launch, the many, many, many things that are involved … it’s not shocking that in that highly complex system that you have a problem. People say space is hard. They say it often, and it’s not tongue-in-cheek and it’s not an excuse. It truly is just a basic fact,” she said. “That we have managed to achieve so much without failure is kind of astonishing.”