SpaceX's recent Starship test flight, Flight 8, experienced a failure stemming from a different root cause than its predecessor, Flight 7, despite occurring at a similar stage of the mission. On May 23, SpaceX released an analysis of the March 6th mishap. Several Raptor engines on the upper stage experienced shutdowns, leading to tumbling and eventual breakup over the Caribbean. While the timing mirrored Flight 7's issues, SpaceX clarifies these are distinct problems. “While the failure manifested at a similar point in the flight timeline as Starship’s seventh flight test, it is worth noting that the failures are distinctly different,” the company stated.
In Flight 8, a central Raptor engine suffered a hardware failure (details undisclosed), causing "inadvertent propellant mixing and ignition" and the loss of that engine. This triggered further engine shutdowns, leading to a loss of control. SpaceX responded by implementing changes, including "additional preload" on Raptor engine joints, a new nitrogen purge system, and propellant drain system improvements. Future Raptor iterations will also incorporate reliability enhancements to mitigate similar occurrences.
Flight 7's failure, in contrast, resulted from an unexpectedly strong harmonic response stressing the propulsion system, causing leaks and an engine bay fire. SpaceX noted that the countermeasures implemented after Flight 7 to address harmonic response and flammability worked correctly before the Flight 8 failure.
Following the Federal Aviation Administration's approval, Flight 9 is scheduled for no earlier than May 27. This mission features the first reflight of the Super Heavy booster from Flight 7 (with some component replacements). A significant change involves ditching the planned booster recovery at Starbase. This flight will test new flight profiles focused on optimizing propellant use for boostback and descent, along with new engine landing profiles. "To maximize the safety of launch infrastructure at Starbase, the Super Heavy booster will attempt these experiments while on a trajectory to an offshore landing point,” SpaceX stated, with a planned "hard splashdown".
The Starship upper stage will attempt previously planned demonstrations, including a space-based Raptor engine relight, deployment of Starlink satellite simulators, and further reentry tests.