Elias Thorne: Ice Puzzle 🧊🌌 Mystery Solved?

It’s difficult to overstate the significance of SpaceX’s comeback following the initial failure of its first Falcon 9 launch. On December 21, 2015, the company successfully launched the Orbcomm-2 mission using an upgraded version of the rocket. Notably, this marked the first time a Falcon 9 first stage had been successfully landed – a historic achievement detailed extensively in “Reentry,” authored by Eric Berger and published in 2024. To commemorate the tenth anniversary, Ars is reprinting a condensed chapter from the book, offering an inside account of this pivotal landing. The story begins in June 2015 with a devastating event: the disintegration of a Falcon 9 rocket carrying the CRS-7 cargo supply mission for NASA, representing the first-ever loss of a Falcon 9 in flight. Seconds after the Dragon-bearing rocket broke apart over the Atlantic Ocean, David Giger, then shortly out of graduate school and having quickly risen to manage the entire Dragon program reporting directly to Elon Musk, shouted into his headset, “Dragon is alive!” Throughout his decade with the company, Giger provided leadership support to the Dragon mission team, largely comprised of younger engineers, as they reacted to the video of debris returning to Earth – a scene reminiscent of the earlier C2 mission in 2012, which had involved many of the same individuals who had since moved on to other positions.

“They were a great team, but I think everyone assumed it was over,” Giger said. Despite enduring several challenging periods at SpaceX, including three failures of the Falcon 1 rocket, Giger remained involved. Following the Falcon 9’s breakup, he observed that Dragon continued to transmit data from approximately thirty miles above the Atlantic Ocean. The spacecraft had separated from the rocket and was operating independently. The critical step in saving Dragon involved deploying its parachutes before it descended too close to the ground. SpaceX had not anticipated this contingency nor planned to send commands to Dragon while it was riding on the Falcon 9 rocket. However, in an emergency, the Dragon control center could utilize ground-based antennas to communicate with and control the spacecraft. Controllers in California frantically configured this communications system and issued commands to open the two drogue parachutes—the small, precursor parachutes designed to stabilize the vehicle prior to deploying Dragon’s three main parachutes. The command was sent, but nothing happened; Dragon continued its descent. For about two minutes after the rocket’s breakup, the spacecraft faithfully relayed data. Then, less than a mile above the ocean, below the horizon from the Florida coast, the data ceased. The spacecraft and its 4,000 pounds of cargo plunged into the sea.

The failure of the nineteenth Falcon 9 rocket, known as the CRS-7 mission, stemmed from a critical oversight: the power supply for parachute deployment had been inadvertently left off. This loss proved a sobering lesson for SpaceX, prompting intense meetings led by Elon Musk, who repeatedly expressed his frustration with the Dragon spacecraft’s malfunction. “Dragon shouldn’t be fucking stupid,” he would often remark to the team, including Giger and other Dragon officials, “It should have saved itself.” Following the CRS-7 failure in June 2015, SpaceX integrated an emergency scenario into the rocket’s launch procedures, enabling the potential for Cargo Dragon to be salvaged if needed. The high-profile failure occurred at a pivotal time for the company, which had been steadily gaining momentum after five years of successful work with Falcon 9 and Dragon, securing lucrative commercial satellite contracts and receiving significant investment from NASA with the goal of eventually launching humans aboard Dragon. However, the CRS-7 explosion significantly disrupted these advancements. Adding to the pressure, Orbital Sciences had experienced a similar setback just half a year prior, when its Antares rocket exploded above the launchpad. This intensified criticism of NASA’s support for commercial spaceflight, highlighting the challenges facing the agency's ambitions in the burgeoning space industry.

The initial setback, coupled with a flight rate of just five launches between mid-2010 and mid-2013, raised significant questions regarding the trustworthiness of private companies in human spaceflight. Frustrated by this slow cadence, Elon Musk tasked Brian Mosdell, the Florida site director, with dramatically increasing the Falcon 9 launch frequency to more than one rocket per month. Mosdell’s responsibilities extended beyond simply boosting launch rates; he also led SpaceX’s efforts to secure a lease for Launch Complex 39A, the most historically significant launch pad in the Western Hemisphere. Situated in a sprawling 200-acre site within Florida’s swampland, just a few feet above the Atlantic Ocean, the location held particular importance, having been the site of numerous launches, including those that carried Neil Armstrong and Buzz Aldrin to the Moon. Following the shuttle program’s retirement in 2011, NASA deemed the facility “unneeded infrastructure,” representing a substantial annual maintenance cost of millions of dollars. With SpaceX already operating and seeking a location for both Falcon 9 and Falcon Heavy launches, the site presented a logical and compelling choice.

Eventually, crew flights were planned for NASA’s Launch Complex 39A. However, in the spring of 2013, Jeff Bezos emerged as another bidder, driven by a deep appreciation for space history and seeking to lease the site for Blue Origin and its New Glenn rocket. To bolster his proposal, Bezos offered to share the launch complex with SpaceX or another company, a remarkably generous gesture. Despite this, Blue Origin lacked an orbital rocket in 2013 and was not close to developing one. Consequently, NASA awarded a twenty-year lease to SpaceX in September, a victory that reportedly thrilled Elon Musk. He was, however, subtly frustrated by Bezos’s offer, which he perceived as an attempt to block Blue Origin’s access. In an email to Space News, Musk responded with a pointed remark: “If they do somehow show up in the next five years with a vehicle qualified to NASA’s human rating standards that can dock with the space station, which is what Pad 39A is meant to do, we will gladly accommodate their needs. Frankly, I think we are more likely to discover unicorns dancing in the flame duct.” Musk further mocked Blue Origin during internal meetings at SpaceX, frequently stating, “A company must really stink to call themselves BO.” History has proven him correct; Blue Origin failed to have a ready-to-fly orbital rocket from Launch Complex 39A within five or ten years. As of the writing of this book, the company’s New Glenn orbital rocket has yet to make a single launch attempt. Meanwhile, SpaceX has launched more than 100 rockets.

From the old NASA pad, Mosdell played a central role in SpaceX’s successful acquisition of launch pad 39A, contributing significantly to the proposal’s technical materials, schedule, and budget considerations. Following the lease agreement, he gained a comprehensive understanding of the extensive work involved – specifically, the demolition of the former shuttle infrastructure and the construction of a launch tower capable of supporting the Falcon 9 and Falcon Heavy rockets. His team, comprising seventy-two full-time employees and approximately eighty contract welders and other specialized hires focused on the new transporter, was operating at maximum capacity due to Elon Musk’s ambitious goal of monthly launches from SLC-40, requiring employees to consistently work 80 to 100-hour weeks. In January 2014, Mosdell traveled to Hawthorne to meet with Musk and Gwynne Shotwell to discuss staffing levels for the development of Launch Complex 39A. During this meeting, he presented a “lean” team structure designed to manage the design, procurement, construction, and testing phases. He requested the hiring of sixty-eight additional personnel over the subsequent six months, a proposal that was ultimately rejected by Musk. The discussion deteriorated from there, culminating in Musk’s directive: “Go home and work harder.” Recognizing the potential for burnout and declining work quality under these intense conditions, Mosdell raised his concerns with Musk and Shotwell, who repeatedly cited budgetary constraints and the need to secure payment milestones before promising to alleviate the team’s workload.

Mosdell’s meeting in Hawthorne solidified his conviction that fundamental change at SpaceX was impossible. He believed the company would perpetually remain in a state of accelerated development, never achieving a true “cruise phase.” “There was simply no genuine effort to address the core issues,” he stated. “It was going to be a matter of simply shutting down and moving on, a ‘color’ approach – and I resolved not to continue directing my team at the Cape, telling them to simply persevere, because I recognized it was a falsehood.” Throughout his six years at SpaceX, Mosdell had achieved significant results, notably leading the construction of the SLC-40 launch pad, which was built at approximately one-tenth the cost of competitors’ projects. He also served as launch director for six missions, initially employing largely manual launch operations that evolved to automate roughly 90 percent of the countdown process by the end of 2013. Under his leadership, the launch site maintained a flawless safety record. Furthermore, Mosdell spearheaded the campaign to win NASA’s competition for the historic LC-39A site, laying the groundwork for SpaceX’s ultimate success in Florida. However, his efforts ultimately proved insufficient, leading to his resignation. Elon Musk did not express dissatisfaction, viewing Mosdell and his team at Cape Canaveral as lacking the necessary intensity. Musk felt a weekly launch cadence – rather than the monthly pace they were maintaining – was essential, a goal the company wouldn’t achieve for nearly a decade. To fill Mosdell’s role, Musk appointed Ricky Lim, who had joined SpaceX in 2008.

Months spent at Kwajalein during the final three flights of the Falcon 1 rocket marked a formative period for him, witnessing firsthand the early years of SpaceX and the challenges the company overcame, including a near-fatal setback. He subsequently supported operations at Vandenberg, working alongside Zach Dunn and Lee Rosen. Following Mosdell’s departure, Lim was appointed site director at Cape Canaveral, a role that initially lasted just three weeks but ultimately expanded to six years. The launch team at the Cape comprised two distinct groups: one comprised of experienced engineers drawn from legacy rocket companies, such as United Launch Alliance – where Mosdell had previously worked, and the other, a group of newly hired SpaceX engineers. Musk believed Lim possessed a better ability to galvanize the younger talent. Indeed, from mid-2014 onward, SpaceX began to establish a consistent rhythm at the Cape. While there were inevitable hurdles, SpaceX eventually employed over one hundred additional individuals for launch and pad redevelopment in Florida. Remarkably, by April 2015, Lim and his team successfully executed two missions – the sixth operational cargo mission for NASA and a Turkish communications satellite – within just thirteen days of each other from Florida. Recognizing the urgency, Lim stepped aside from his site leadership role to serve as launch director for the subsequent mission, CRS-7, which lifted off on its designated morning.

All went smoothly for the first two minutes of the flight. At 2 minutes and 19 seconds, Lim began to detect chatter on the network regarding “data drops” originating from the second stage. He observed a video displaying the rocket far down range, a white streak ascending into an azure sky, while a vapor cloud surrounded the upper stage. Despite this cloud, the rocket’s nine engines continued to burn effectively. “It was surreal,” Lim stated. “The data we were receiving didn’t match what we were seeing – the first stage was still progressing, and the long-range cameras resembled previous launches.” He initially suspected a ground software display issue or a similar minor problem. A second or two later, the large white cloud expanded rapidly, engulfing the entire rocket. As it dissipated, tracking cameras captured a shower of debris as fragments of the rocket began tumbling back towards Earth. A palpable silence descended upon the flight control room. Elon Musk, observing the launch from England where he was celebrating his forty-fourth birthday, described the event as a “lousy birthday present.” He immediately contacted Burt Dunn, who had recently taken over leadership of SpaceX’s propulsion department after five years of launching rockets, and was observing the launch from within the Mission Control Center in Hawthorne. Dunn explained that he didn't yet have an immediate explanation for the failure and then passed the phone to Jon Edwards

During the launch, engineer Jon Edwards observed what appeared to be a pressure event on the second stage. Within a second or two, the situation clarified as a large white cloud rapidly expanded, completely engulfing the rocket. As the cloud dissipated, tracking cameras captured a shower of debris as fragments of the rocket began their descent back to Earth. A palpable silence settled over the flight control room. Following the event, David Dunn walked out of mission control and returned to the propulsion area, gathering his team for a brief discussion. Dunn informed Elon Musk that he lacked an immediate explanation for the failure and passed the phone to Jon Edwards, who reiterated his observation of a potential pressure event on the second stage. Musk brought considerable energy to the ensuing meetings, emphasizing the need for unwavering focus and precise understanding. He demanded immediate, accurate assessments, and if anyone faltered, he swiftly challenged their conclusions. At that time, Hans Koenigsmann, one of Musk’s most trusted senior executives, served as Vice President of Flight Reliability and Mission Assurance – a role dedicated to guaranteeing safe and successful launches.

“Ultimately, we were responsible for when it went wrong,” he said. “It took five months of around-the-clock work, and I took only one weekend off – I believe it was the only one – while my team worked every day during that period. We worked incredibly hard, and they did, too.” The core challenge in understanding the failure stemmed from the rapid transition: the rocket moved from a normal trajectory to a complete conflagration in just 800 milliseconds. Koenigsmann’s team quickly identified the source of the problem as the second stage, which had not yet separated from the first stage. The speed of the event—a fraction of a second—presented a significant obstacle, leaving engineers and scientists from SpaceX and NASA with only 115 pieces of telemetry data during that critical moment when the upper stage failed. Analysis of this data revealed that the liquid oxygen tank had ruptured following the release of a container filled with pressurized helium. These bottles of helium were present in the LOX tank to maintain downward pressure as the rocket burned propellant and oxidizer during launch. Specifically, helium gas is released to fill the vacated volume, ensuring continuous flow of these fluids into the engines. This composite overwrapped pressure vessel, or COPV, is designed to maintain structural integrity through a strong fiber wrapping around a metallic container.

The investigation revealed why a COPV bottle containing helium had broken loose and catastrophically struck the upper dome of the oxygen tank. Ultimately, structural engineers determined that a small, $4 steel rod end – roughly the size of a Tootsie Pop – was the root cause of the failure. This rod end, also known as a “thumb-sized” part, was responsible for securing the COPV to the oxygen tank wall and fractured during the rocket’s ascent. Koenigsmann explained that these rod ends were typically rated to withstand 10,000 pounds of force, yet one within the ill-fated upper stage failed under less than 2,000 pounds. As part of a rigorous design process, nearly all rockets and spacecraft undergo a “critical design review” before fabrication begins. During this review for the Falcon 9, SpaceX had mandated the use of a more expensive rod end, which cost approximately $50. However, somewhere between this review and the actual flight, a cheaper rod end—manufactured through a casting process—had been substituted. SpaceX subsequently launched a search to locate the broken rod end, a challenging endeavor that involved scouring fifty miles off the coast of Florida, hundreds of feet below the ocean’s surface, resembling a “Don Quixote-like” quest.

The company subsequently deployed a remotely operated submarine to search for wreckage, ultimately discovering long-lost hardware from both the Apollo and Space Shuttle Programs, though no Falcon 9 components were recovered. Despite this, Koenigsmann remained confident that a cast rod end was the root cause of the failure, citing SpaceX’s own testing of similar parts from the same purchase order, which revealed they were prone to breakage under cryogenic conditions. The question then arose: why had SpaceX switched to a less expensive cast rod end? This shift, he noted, reflected a company-wide culture instilled by Musk – a constant drive to minimize costs. Someone within SpaceX determined that a $50 rod end represented an excessive expense, leading to its substitution with a cheaper alternative. Given that every strut on the rocket utilized rod ends, the change resulted in the replacement of hundreds, ultimately saving over a thousand dollars on the launch vehicle. Musk and his team’s relentless focus on cost control led to such decisions countless times. Had Musk not exercised such careful consideration of expenses, the price of a Falcon 9 would have significantly increased. And, in almost every instance, this approach proved successful – except in this specific case. In the fall of 2015, Koenigsmann submitted a detailed report outlining SpaceX’s findings to both NASA and the Federal Aviation Administration. The report concluded that “material defects” were the most probable cause of the broken rod end, effectively placing the blame on the supplier. However, NASA’s own independent investigation delivered a more critical assessment, directly attributing the failure to a “design error” by SpaceX. The space agency also stated

SpaceX’s quality control process failed to identify the substandard rod ends prior to their installation on the rocket. As detailed in the report, the implementation lacked adequate screening and testing of the industrial-grade part, disregarding the manufacturer’s recommended 4:1 factor of safety for its use in a critical application, and omitting proper modeling and sufficient load testing under predicted flight conditions. “SpaceX and the supplier made a critical error,” Koenigsmann stated. The rocket failure significantly increased the US space agency’s reliance on Russia. For several months following the incident, the sole means of transporting American astronauts to the space station and supplying them with necessities was a pair of small spacecraft, originally designed during the Soviet era, launched from Kazakhstan. Despite these issues, NASA refrained from publicly criticizing SpaceX. During a 2016 US Senate hearing, when some elected officials would have seized the opportunity to denounce the company, NASA’s chief of human spaceflight defended SpaceX. Bill Gerstenmaier told Congress that SpaceX responded “very quickly,” initiating testing within days at a ground-based facility. He noted that the company’s reaction – immediately conducting testing – was considerably faster than what NASA would have been able to accomplish at the time.

SpaceX, seeking to compensate NASA for the Atlantis cargo mission failure, finalized the proposals and implemented the test sequence, which would have taken approximately six months. Shortly after the accident, the company quietly agreed to conduct five future cargo missions – flights sixteen through twenty – to the space station at significantly discounted rates. Furthermore, SpaceX increased the cargo capacity of each Dragon mission, providing NASA with greater value. However, this arrangement relied on the successful return to flight of the Falcon 9 rocket. Even if the cargo mission had not failed, the Falcon 9 still faced several months of downtime during the second half of 2015. Elon Musk determined that the rocket required a substantial upgrade to version 1.2, later known as the Falcon 9 Full Thrust. This represented a major advancement in the rocket’s capabilities. Crucially, drone ship landings were integral to the economic viability of first stage reuse; however, SpaceX also focused on maximizing the rocket's performance. No aspect of the Falcon 9 was left untouched, with SpaceX engineers producing a redesigned machine that boosted the rocket's lift capacity by almost one-third. The propulsion department developed an enhanced Merlin 1D engine, increasing engine thrust by approximately 15 percent. The structures department created a lighter rocket design, facilitating easier manufacturing, and incorporating the knowledge gained throughout the process.

Grasshopper program design and subsequent landing attempts in the Atlantic Ocean heavily influenced the development of the new rocket legs and control systems. Crucially, the most significant upgrade involved a technology called propellant densification – effectively maximizing the amount of fuel onboard. While the concept may initially seem complex, the science and engineering behind super-chilling rocket fuel proved to be both fascinating and incredibly risky. Just one year after seriously pursuing densification, SpaceX successfully detonated liquid oxygen and kerosene aboard the Falcon 9, achieving an additional 8 to 10 percent performance boost. This represented a substantial improvement, enabling the vehicle to carry two more tons of payload to orbit. Consequently, Elon Musk recognized densification as a critical factor in the economic viability of the Falcon 9. Liquid oxygen possesses a pale blue, ghostly color and condenses at –297.33 degrees Fahrenheit (–182.96 degrees Celsius), a temperature far colder than the coldest recorded on Earth in Antarctica, and even colder than the darkest regions of the Moon. This extreme cold presents significant challenges when working with liquid oxygen; however, its properties – specifically, its 1,000 times greater density compared to gaseous oxygen – make it the preferred fuel for most rockets. SpaceX’s ambition was to further enhance this density by chilling the liquid oxygen almost to a solid state, a foundational application of basic chemistry, where lower temperatures increase a substance's density.

In 2015, SpaceX engineers, including Phillip Rench, sought guidance from the National Institute of Standards and Technology (NIST), a Maryland-based agency recognized as the world leader in measuring physical properties. The team, led by Muratore and Vincent Werner, were investigating the potential of densifying liquid oxygen, a process that relied on achieving extremely low temperatures. They had been studying tables published by NIST that detailed the temperatures and pressures at which oxygen, nitrogen, and liquid air—primarily a mixture of oxygen and nitrogen—transformed into solids. According to Muratore, the NIST researchers cautioned that these tables were extrapolated and represented the furthest known limits of experimentation, acknowledging potential inaccuracies of a degree or two, or a psi or two. SpaceX’s ambition was to produce vast quantities of densified oxygen, hundreds of thousands of gallons for a single rocket launch. Phillip Rench, a graduate of Southern New Hampshire University with a degree in mathematics – a background not traditionally associated with aerospace – led a small team of eight engineers in Cape Canaveral responsible for the practical work of producing the ultra-dense oxygen.

Nearly a decade spent at SeaWorld in Orlando provided Rench with a diverse range of experience, from underwater maintenance and amusement park ride repairs to developing solutions to complex problems. During his time there, he cultivated a knack for devising innovative approaches, particularly with valves and other components used in control systems. This interest was sparked by a promotional video showcasing a Falcon 9 rocket launch and landing in Florida, leading him to apply to SpaceX early in 2014 and secure a position assisting with modifications to Launch Complex 39A. He witnessed the CRS-7 launch firsthand from the vantage point of this pad, alongside other engineers, technicians, and interns at the former NASA site. “Everyone was incredibly depressed,” he recalled. “But the next day we came back at 150 percent, with energy and passion – you know, the five stages of grief? We went through that really quickly.” Engineers at McGregor had conducted preliminary densification tests, and some early work in Florida was spearheaded by Brian Childers and Gavin Petit. Rench collaborated with a team including Petit, David Ball, Chris Wallden, and others. Notably, the Florida crew’s initial approach, lacking practical experience with super-chilled oxygen, involved simply connecting equipment and observing the results. SpaceX utilized liquid nitrogen to chill liquid oxygen – a colorless gas that transforms into a liquid at –320 degrees Fahrenheit (–196 degrees Celsius) – a temperature substantially lower than that of LOX. The engineering team then flowed the liquid oxygen to further chill it.

Through a pipe, a coil of tubing filled with liquid nitrogen circulated, and the two substances never mixed; instead, the warmer LOX shed heat into the liquid nitrogen. SpaceX utilized powerful vacuum pumps to actively remove this heat. Over the course of several weeks, as the pressure decreased, the temperature of the nitrogen fell below –340 degrees Fahrenheit (–210 degrees Celsius), and the liquid oxygen followed suit. It was impossible to achieve further reductions, as nitrogen freezes at –346 degrees Fahrenheit (–210 degrees Celsius). Rench deeply enjoyed the work, having dedicated years to developing valves and other systems to meticulously control the flow, temperature, and pressure of the liquids. When his team pushed liquid oxygen to its extreme, the operation resembled a SeaWorld environment. The team worked in pairs, maintaining eight-hour shifts, seven days a week, during which the nights were notably eerie, accompanied by unusual noises. “Liquid oxygen does not want to be densified,” Rench explained. “Densification produces this low, horrible growl.” Initially, when the team began densifying the LOX, Praxair delivery drivers would pump the warmer LOX into the sphere, resulting in unsettling, erratic noises, causing them to become understandably nervous – a group comprised of individuals who had spent their careers working with liquid oxygen. Ultimately, NASA had been

Skeptical about SpaceX’s plans for densification at Launch Complex 39A, NASA requested a demonstration. Following SpaceX’s delivery and NASA’s approval, the fluids team began removing the parts and pumps associated with the LOX chiller system. These were required at SLC-40 to support the densified propellant needed for the debut flight of the Falcon 9 Full Thrust. After two unsuccessful drone ship landings, Elon Musk determined he was ready to attempt landing the rocket on land, a significant advantage over ocean recovery due to the absence of high seas. Ground offered a stable surface – flat and unmoving – but presented a considerable challenge: the returning Falcon 9 would fly near cruise ships in Port Canaveral, the National Reconnaissance Office’s multibillion-dollar Eastern Processing Facility, and numerous other launch pads and valuable assets. SpaceX acquired Launch Complex 13 in February 2015 specifically to facilitate the return of the rocket. Trip Harriss, who had been with the company since its Falcon 1 days on Kwajalein, took on responsibility for Falcon recovery efforts and spearheaded the construction of Landing Zone 1. He and Bala Ramamurthy also worked to persuade the Range commander to authorize SpaceX to aim rockets at the Air Force station – a novel approach. “As the Range commander,” stated General Wayne Monteith, who commanded the 45th Space Wing at Cape Canaveral from 2015 to 2018, “you’re used to rockets going away from you. So when you see one that’s 180 feet tall…”

As the individual responsible for the safety of all personnel on the installation, you begin to feel a rising concern as the “career dissipation light” blinked. Harriss and SpaceX provided data to convince Monteith and other Air Force officials of the project’s safety, particularly following ocean landings that, though unsuccessful, had come remarkably close to impacting the drone ship. Monteith felt confident that should SpaceX damage any property at the Cape, it would be the company’s own equipment. Furthermore, SpaceX demonstrated that the vast majority of the booster’s return flight profile occurred over water. A destruct signal could then be sent to the first stage before it posed a threat to the shoreline. Before approving a landing attempt, Monteith needed to secure the confidence of his supervisors, who were acutely aware of the potential risks. Opposition grew louder as the weeks progressed toward SpaceX’s return to flight, driven largely by concerns from the National Reconnaissance Office regarding the rocket’s sonic boom. Range safety analysts predicted the Falcon 9 flyback would generate a sonic boom comparable to the 2013 Chelyabinsk meteor event in Russia, potentially damaging buildings and homes in the Cape Canaveral area. Given the inherently risk-averse nature of the operation and the potential consequences of a failure, Monteith understood that ultimate responsibility rested with him.

During the process of allowing SpaceX to land at Cape Canaveral, it became clear that the decision placed a significant responsibility on his shoulders. “During a meeting, a commander’s call, I stood up and stated that I believed this was the correct course of action,” Monteith explained. “I understood at that point that if anything went wrong, I would face termination.” In early December, SpaceX received approval from the Air Force to not only launch a missile but also to return it to the International Space Station. This was notable because SpaceX was utilizing a newly tested version of its Falcon 9 rocket, which was returning to flight following a previous launch failure and carrying densified propellant for the first time. Predictably, the lead-up to the launch was chaotic. Following the resolution of a critical “rod end” issue in collaboration with NASA and the Federal Aviation Administration, and after securing permission from the Air Force to perform a targeted return to the Cape, SpaceX still had to refine new procedures for handling the densified oxygen. A key challenge presented by the densified oxygen was the inability to reattempt the launch if there were technical difficulties or adverse weather conditions at the scheduled liftoff time. Once the super-chilled propellant was loaded onto the rocket, SpaceX had only minutes to launch, or the liquid oxygen would become too warm, rendering it unusable. Offloading the warmed liquid oxygen to a storage vessel – the LOX ball – would also spoil the colder oxygen contained within that vessel. Dumping all of the rocket’s LOX was, of course, entirely impractical, as it would have caused damage to the launch site’s pipes and other equipment.

As launch director, Lim maintained a close watch on the calendar, acutely aware of SpaceX’s targeted launch date of December 21, 2015, for the return to flight. The Falcon 9 rocket was tasked with lofting eleven satellites for telecommunications company ORBCOMM into low-Earth orbit, carrying a total mass of approximately 4,500 pounds. This relatively light payload afforded the rocket sufficient fuel reserves to return to Landing Zone 1. The team had worked intensely, and many anticipated a few days off during the holidays, with several discussing potential departures if a launch window didn’t materialize. “We were desperately trying to save Christmas,” Lim stated. “Our employees had been working months on end, and I worried that about a third of them might leave. If we scrubbed and plowed through the holidays, it would just have been murder.” From the company’s control center, situated roughly eight miles from the launch pad, Lim directed the launch. The countdown was particularly tense, culminating in a camera inside the interstage area between the first and second stages revealing drops of a pale blue liquid dripping down. This presented a novel problem due to the team’s initial use of densified propellant, and could potentially indicate a serious issue—kerosene leaks could cause a fire, while liquid oxygen could lead to an explosion. After meticulously reviewing data and video, the launch team determined the substance was likely “liquid air,” or air that had been cooled to cryogenic temperatures.

Temperatures near the frigid tanks prompted a hurried discussion among the launch team regarding a detected leak. At T-1 minute, Koenigsmann addressed Elon Musk, stating, “You’ve got to make a decision.” Musk typically delivered his decisions with confidence and a commanding presence, but in this critical instance, he responded with a casual, almost detached, demeanor: “Well, I guess we’re going.” The upgraded version of the first stage performed flawlessly, successfully delivering the second stage before the rocket burned for its return journey, descending from the black night towards the Florida coast. As the rocket approached land, the launch control center observed a spectacular orange glow and a significant cloud of dust as it disappeared behind the tree line. Suddenly, a massive, building-shaking blast occurred. “That scared the shit out of us,” Koenigsmann admitted. Both Musk and Koenigsmann initially feared a rocket explosion. However, someone on the launch team suggested reviewing the video feed from the landing site, which revealed a vastly different outcome. The Falcon 9 rocket was intact, standing upright on the landing pad and emitting a light smoke amidst the mild Florida evening. It transpired that the room's reaction was caused by the delayed sonic boom from the reentering rocket. The room erupted in applause and cheers as Musk’s mood dramatically shifted – he became delirious with joy, brimming with happiness and pride.

The culmination of countless hours and unwavering dedication was realized as the moment arrived. His steadfast belief in successfully returning rockets from orbit and landing them – often met with skepticism – had been definitively validated. Like a child in a candy store, Elon Musk repeatedly urged Lim and the launch team to visit the landing pad and observe his rocket. Three individuals who had worked alongside Musk for years confirmed they had never witnessed him so genuinely happy. SpaceX had proactively negotiated range safety protocols with the Air Force, anticipating a potential landing scenario. The rocket remained equipped with onboard explosives, including the TEA-TEB ignition fluid, the rope-like flight termination system, liquid oxygen, and kerosene. A dedicated safety team was first required to secure the vehicle. The successful launch of the new rocket and its unprecedented landing represented a complete triumph. “It’s difficult to describe how epic this comeback was after our initial Falcon 9 launch failure,” Koenigsmann noted. As Musk, Koenigsmann, and the others gazed up at the sooty rocket, bathed in the glow of floodlights beneath a dark and starry sky, they understandably wondered if this extraordinary moment could ever be surpassed. Excitement was palpable at SpaceX headquarters in Hawthorne as well. Upon the rocket’s touchdown, a throng of employees crowded onto the factory floor outside mission control, erupting in chants of “U-S-A! U-S-A! U-S-A!” A boisterous celebration ensued. Indeed, the four thousand employees of SpaceX had achieved nothing short of a remarkable feat in the six months leading up to that night, managing four separate, massive projects simultaneously.

The late-December launch, aboard the Falcon 9 rocket, represented SpaceX’s return to flight mission, incorporating a significant upgrade to the Full Thrust version alongside an unprecedented oxygen densification program and the company’s first successful landing. This mission, remarkably, “saved Christmas,” as it were. The historic ORBCOMM launch and landing delivered one of the most cathartic and breathtaking moments in SpaceX’s history, a feeling I believe is impossible to overstate. Following a terrible and financially disastrous failure, the company roared back with this accomplishment, achieving something no company, or country, had ever done before. Until that night, SpaceX had largely mirrored NASA and other organizations in launching rockets, deploying satellites into space, and landing spacecraft in the water – albeit in a cheaper, more innovative manner. However, these were well-established pathways. No organization had previously launched an orbital rocket and landed it back on Earth within minutes. Catriona Chambers joined SpaceX in early 2005 as an electronics engineer, and within months, she assumed responsibility for the Merlin engine computer on the Falcon 1 rocket. During the Falcon 1’s initial launch, she oversaw a sensor that measured atmospheric pressure; upon reaching space, the first stage would descend back to Earth, and when the sensor detected a thickening atmosphere, it would command the deployment of a parachute.

Rocket Chambers, SpaceX’s director of avionics, knew the situation was preposterous: the rocket’s survival was highly improbable, and the parachute would be largely ineffective. Yet, from the very beginning of SpaceX, Elon Musk relentlessly advocated for the reuse of launch vehicles. Eleven years later, she was observing the concept become reality as her team watched the first stage land. “That was the point where it really sunk in that we had been working on this for so long,” Chambers said, feeling a surge of excitement mixed with the need to calm down – she was eight months pregnant, after all. Zach Dunn, who had taken over the propulsion department in February with the goal of completing the Merlin engine upgrades for the Full Thrust version of the Falcon 9, experienced a similar blend of exhilaration and relief at the launch of the ORBCOMM mission. Within the first couple of weeks, two engines failed during testing. This was compounded by the subsequent failure of the CRS-7 launch, which triggered a tortuous investigation. The propulsion team then faced the arduous task of preparing the new rocket and updating the launch site for densified propellant, a process that consistently presented difficulties right up until the launch date. On December 18th, the company had to abort three separate static fire test attempts as the launch team continued to learn, on the fly, how to properly load and offload super-cold liquid oxygen. Elon Musk then entered the control room, a moment Chambers described as inevitably impactful.

The situation had quickly escalated, raising the level of tension and urgency. Dunn explained to Musk that by the time the rocket was ready for ignition, the propellant would be warmer than the engines were designed to handle. Despite his team’s concerns—who had advised against the test due to the expected data limitations—Musk instructed Dunn to proceed. “My engine team was telling me this was not the right thing to do,” Dunn recalled. “That we weren’t going to get the data we needed from the test. The pressure from Elon was just absolutely intense.” On launch day, Dunn found himself seated beside Shotwell in Hawthorne’s mission control. As soon as the booster successfully touched down, Shotwell sprang to her feet, joining in the celebratory mood. After a few minutes of shared enthusiasm, Dunn departed to walk across the factory floor to the propulsion area, where approximately fifty-seven engineers – almost the entirety of his propulsion department – were gathered. “It had been a hard fucking year,” Dunn stated. “This was my hardest year at SpaceX, leading propulsion, going through those failures and trying to keep the team together, and the pressure of getting back to launch. It pushed my leadership and technical abilities to their limits. My interface with Elon was more direct and more intense than it had been before.” As Dunn approached his desk, the other engineers rose one by one, then in a sudden rush, to offer a standing ovation—a completely unexpected gesture. Dunn had arrived at SpaceX as an outsider, having previously overseen pad operations at Vandenberg. The propulsion department at SpaceX was characterized by a significant number of egos and considerable technical expertise.

Over the previous ten months, Dunn had been a member of and frequently fought alongside this team, experiencing both victories and defeats. However, following that particular night, his role shifted significantly; he was no longer solely their leader, but rather one of them. “I’ve never felt better in my life,” Dunn stated. “It felt incredible to experience that after what I consider to be the hardest fight I’ve ever faced professionally.”