Starship Flight 9 ends in uncontrolled re-entry — what caused the rocket's third failure?

SpaceX's Starship experienced another test flight failure on May 27, marking the third failure of the rocket in a row. After successfully reaching space, the spacecraft lost attitude control, leading to an uncontrolled re-entry. The launch from Starbase, Texas, was briefly delayed due to a ground equipment issue. This Flight 9 mission aimed to resolve the engine problems that plagued the two previous flights in January and March, with particular focus on the performance of Starship's six Raptor engines during a nearly six-and-a-half-minute burn, per SpaceNews.

Unlike earlier flights, the engines on this Starship test seemed to work correctly, shutting down as planned after pushing the vehicle into its intended suborbital path. However, video from the vehicle right after engine shutdown indicated that it was expelling propellants and slowly rolling. About 30 minutes after liftoff, SpaceX confirmed an issue with Starship. Dan Huot, a host for the SpaceX webcast, stated, “We are in a little bit of a spin. We did spring a leak in some of the fuel tank systems inside Starship.” He added, “At this point, we’ve essentially lost our attitude control with Starship.”

Because of this loss of attitude control, a controlled re-entry was impossible. SpaceX decided to “passivate” the vehicle by venting the remaining fuel before it reentered the atmosphere. Sporadic video feeds showed Starship beginning its re-entry a little over 40 minutes after liftoff, with visible damage to a flap before telemetry was lost at T+47 minutes into the flight. The re-entry occurred over a part of the Indian Ocean where air and sea navigation warnings had been put in place. 

Elon Musk, the CEO of SpaceX, commented on X after the vehicle's loss, attributing it to "leaks caused loss of main tank pressure during the coast and re-entry phase. A lot of good data to review.” He also indicated that the “launch cadence for next 3 flights will be faster, at approximately 1 every 3 to 4 weeks.” The original plan for this mission involved opening Starship's payload bay door to release eight simulated next-generation Starlink satellites, which were also intended to follow suborbital paths and reenter separately from Starship. However, the payload door did not fully open, and as a result, the release of these simulated satellites was cancelled. It was not immediately clear if the payload door's failure to open was connected to the propellant leak and the subsequent loss of attitude control. SpaceX also cancelled plans to reignite a Raptor engine in Space. The uncontrolled re-entry prevented SpaceX from testing the alternative heat shield tiles or deliberately stressing vulnerable parts of the vehicle, as originally intended, reported the outlet. 

Furthermore, SpaceX did not meet all its test objectives for the Super Heavy booster. This flight marked the first time a previously used booster, B14 (which had flown on Flight 7), was utilized. SpaceX had stated before the launch that it would not attempt to return the booster to the launch site, instead focusing on tests designed to optimize the vehicle's flight profile and conserve propellant. These booster tests initially seemed to go as planned. However, the vehicle was destroyed when its engines ignited for what was intended to be a final landing burn.