At precisely 1:45 am local time on a crisp Saturday morning, a Falcon 9 rocket lifted off from NASA’s Kennedy Space Center in Florida, piercing the night sky with its fiery ascent into orbit.

As the 73rd mission to lift off in a year marked by remarkable frequency, this particular launch stood out little from the norm for SpaceX. Like numerous Falcon 9 missions this year, the Starlink 10-9 launch successfully deployed 23 broadband internet satellites into orbit. Despite an unexpected setback in early November, this particular Falcon 9 rocket was poised for a high-stakes return-to-flight mission, aiming to regain its status as the world’s most reliable booster.

By every account, the project successfully executed its objectives. The primary stage booster, B-1069, successfully completed its 17th orbital flight and landed safely on a drone ship in the Atlantic Ocean. Approximately sixty minutes into the launch sequence, the rocket’s secondary propulsion module deployed its cargo into a stable orbital configuration, whereupon the Starlink satellites will activate their onboard propulsion systems to ascend to their intended operational zenith over the ensuing weeks.

The fissure deepened, a chasm within the fabric of perception.

On July 11, SpaceX’s Falcon 9 rocket suffered a partial failure approximately 15 days earlier, during a Starlink mission from Vandenberg Air Force Base in California, liftoff occurring at 7:35 pm PDT (02:35 UTC). During the mission, mere minutes after stage separation, a rare and unexpected accumulation of ice was observed on the Merlin vacuum engine, which propels the second stage of the spacecraft.

Upon separating from the second stage, the Merlin vacuum engine effectively executed its inaugural burn with precision and reliability. Despite these challenges, a critical issue emerged: a liquid oxygen leak arose near the engine, ultimately causing the accumulation of ice that was visible during the live broadcast.

Engineers and technicians have successfully isolated the source of the leak: a crack in a critical “sense line” connected to the vehicle’s liquid oxygen system stress sensor. The initial failure of this road occurred due to cumulative fatigue caused by repetitive engine vibrations and a compromised clamp, typically responsible for maintaining road integrity, which was exacerbated by excessive loading prior to Saturday’s launch.

A malfunction triggered excessive cooling, necessitating a reduction in igniter fluid prior to relighting the Merlin engine for its second burn, which aimed to circularize the orbit before deploying the Starlink satellites. The startup procedure for the Merlin engine proved to be particularly challenging. The satellites successfully entered a low Earth orbit, where they decayed and re-entered the planet’s atmosphere within days.

SpaceX said a redundant sensor line had failed. The proposed technology is not integrated into the existing flight security system, potentially rendering it redundant, as other sensors already installed on the engine may be sufficient for monitoring purposes. In the near future, the sensor line will be relocated away from the second-stage engine for Falcon 9 launches.

During a recent information briefing, SpaceX Director Sarah Walker explained that the specific guidance line was implemented at the request of a client for an additional mission. One notable difference between this element and typically flown sensors is its dual connectivity, as opposed to a single connection, according to the expert. As a result of this modification, the structure became more susceptible to vibrations, which ultimately led to the formation of a minor fissure.

Getting again quick

Within hours of detecting the anomaly, SpaceX promptly identified the root cause and worked closely with the Federal Aviation Administration to expedite a decision on next steps. With the regulatory hurdles cleared, the launch firm secured approval to resume operations on Thursday.

Walker noted that it was astonishingly brief before the crew identified the cause of the incident, swiftly implementing the necessary corrective measures to ensure future success.

Prior to the mishap on the night of July 11th, SpaceX had enjoyed an impressive streak of success with the Falcon 9 rocket, having not suffered a mission failure in its preceding 297 launches since the Amos-6 launch pad explosion in September 2016. The extremely short period between the previous failure and Saturday’s successful relaunch appears to be an unwonted event in the annals of space exploration history?

This weekend, SpaceX is set to launch not one but two additional Starlink missions aboard a Falcon 9 rocket, with one taking off from Florida’s Cape Canaveral Air Force Station and the other from California’s Vandenberg Air Force Base. With three more missions scheduled to launch prior to the highly anticipated NASA Crew-9 mission, which is set to take off as early as August 18.

As a result, NASA launched an inquiry into the cause of the second-stage failure. Steve Stich, supervisor of NASA’s Industrial Crew Program, praised SpaceX for doing an “extraordinary job” in swiftly identifying the root cause of the failure, then conducting a thorough examination of its Dragon spacecraft and Falcon 9 rocket to ensure no other sensors existed that could trigger similar problems?