### SpaceX Probes Falcon 9 Upper Stage Failure Following Crew-9 Launch
On Saturday, SpaceX accomplished the launch of its Crew-9 mission, transporting NASA astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov to the International Space Station (ISS). Nonetheless, the mission faced complications due to an unforeseen issue with the Falcon 9 rocket’s upper stage, which reentered Earth’s atmosphere and landed in the ocean outside the designated disposal zone. This event has led SpaceX to investigate the failure, marking the third incident involving the Falcon 9 rocket in just three months.
#### Crew-9 Mission: A Triumph with a Caveat
The Crew-9 mission took off from Cape Canaveral Space Force Station in Florida, where the Falcon 9 rocket’s second stage Merlin vacuum engine operated for over six minutes to position the Crew Dragon spacecraft into low-Earth orbit. Hague and Gorbunov successfully arrived at the ISS on Sunday, commencing their five-month tenure aboard the orbiting laboratory.
While the mission was largely successful, the Falcon 9’s upper stage ran into difficulty during its deorbit burn. The upper stage was expected to reignite its Merlin vacuum engine to navigate back into Earth’s atmosphere for disposal in the South Pacific Ocean. This procedure is intended to prevent the rocket from becoming space debris. However, an “off-nominal deorbit burn” was reported by SpaceX.
> “Following today’s successful launch of Crew-9, Falcon 9’s second stage was disposed of in the ocean as outlined, but experienced an off-nominal deorbit burn,” SpaceX stated on X (formerly Twitter). “Consequently, the second stage landed safely in the ocean, but outside the designated area. We will proceed with launching after we gain a clearer understanding of the root cause.”
#### Understanding the Malfunction
SpaceX has yet to provide extensive details regarding the malfunction, but experts have offered potential explanations. Jonathan McDowell, an astrophysicist and spaceflight authority, indicated that the likely failure mode was a “slight underburn” of the Merlin vacuum engine. This could have resulted in the rocket veering off trajectory and reentering the atmosphere further northeast than planned over the Pacific Ocean.
The malfunction transpired during the second burn of the Merlin vacuum engine, which is essential for steering the upper stage to its disposal location. While the majority of the rocket was anticipated to disintegrate upon reentry, SpaceX aims for remote ocean zones for disposal to limit the chance of debris impacting populated areas.
#### A Series of Recent Falcon 9 Issues
This occurrence signifies the third time in under three months that SpaceX has encountered challenges with its Falcon 9 rocket, concluding a remarkable sequence of flawless launches. The initial recent failure took place on July 11, 2024, when the upper stage of a Falcon 9 rocket failed to position a batch of 20 Starlink satellites into their expected orbit. The satellites reentered the atmosphere and were destroyed. This incident represented the first mission failure for the Falcon 9 in 335 launches, an unparalleled achievement in spaceflight history.
Engineers attributed the July failure to a crack in a “sense line” relating to a pressure sensor in the rocket’s liquid oxygen system. This defect caused a leak that inhibited the upper stage’s second burn. SpaceX subsequently replaced the redundant sense line and resumed launches 15 days later.
Another issue arose on August 28, 2024, when a reusable Falcon 9 booster toppled after landing on a drone ship in the Atlantic Ocean. Although the primary objective—a Starlink satellite launch—was successful, this incident marked the first time SpaceX lost a rocket after successfully landing 267 boosters in succession.
#### FAA Participation and Public Safety Considerations
In the aftermath of both the July 11 and August 28 incidents, the Federal Aviation Administration (FAA) mandated SpaceX to investigate the failures. The FAA, which issues licenses for commercial launch vehicles, is tasked with ensuring that launch and reentry procedures do not pose a threat to public safety. Following these investigations, the FAA provided “public safety determinations” permitting SpaceX to continue with Falcon 9 flights.
As of early Monday, the FAA had not indicated whether it would require an investigation into the most recent upper stage malfunction. Nonetheless, SpaceX has already delayed its next Falcon 9 launch, initially set for Sunday night from Vandenberg Space Force Base in California. Another Falcon 9 mission from Cape Canaveral, originally scheduled for Wednesday, has also been postponed.
#### Impacts on Upcoming Missions
While the recent upper stage malfunction is not expected to sideline the Falcon 9 rocket for a prolonged duration, it arises at a pivotal moment for SpaceX. The Falcon 9 has established itself as a staple in the aerospace sector, averaging approximately one mission every three days. However, several notable interplanetary science missions are currently
