Investigation prior to launch Starship flight test 3 in March 2024 attained full duration burns of both stages and reached orbital velocity. However, both stages were destroyed during
atmospheric return, prompting a SpaceX-led mishap investigation overseen by the
FAA. The FAA stated that a completed license modification, incorporating corrective actions and meeting other requirements, was required for a launch license to be granted for this flight, the fourth flight test. SpaceX stated in early April that it would intend to attempt a booster landing with the tower arms on the fifth flight test if the booster virtual landing is successful during the fourth flight test. In late April, a NASA official confirmed SpaceX remained on track for the fourth test flight to occur in May 2024. The communications license necessary for Flight 4 was granted by the
FCC on April 18. On May 17, SpaceX asked that the
FAA make a public safety determination regarding the third flight test, which would allow SpaceX to launch the test flight while the mishap investigation is in progress if determined there was no public safety danger. The FAA concluded the investigation on May 28 and determined that the third flight test had not threatened public safety. SpaceX received regulatory approval to launch from the FAA on June 4. Starship flight test 4 was initially scheduled to launch on June 5, but was pushed back a day to June 6. For this fourth flight test, the FAA listed three specific outcomes that would not trigger a mishap-investigation: the ship burning up during reentry, the flaps not having sufficient control of the ship, or the Raptor 2 engines failing to relight for landing.
Vehicle ground testing Booster 11 and Ship 29 were first spotted around August 2022. Both stages underwent multiple cryogenic proof tests in late 2023, with Ship 29 performing a
spin prime test in March 2024. Following Starship's third test flight, Ship 29 was lifted onto Suborbital Pad B for two static fire tests in late March, and was later returned to the
High Bay for pre-flight modifications. A 33-engine static-fire was conducted on Booster 11 on
Orbital Launch Mount 1 on April 5.
Booster 11's hot-staging ring was installed in early May. Ship 29 was lifted onto Booster 11 on May 15, followed by a partial propellant load test on May 16. A
wet dress rehearsal (WDR) was conducted on May 20. On May 28, SpaceX performed a second wet dress rehearsal of S29 and B11, and on May 30, SpaceX installed the
flight termination system (FTS or AFSS) on B11 and S29. On June 5, S29 was stacked on top of B11 for the fourth and final time. SpaceX intentionally omitted two
TPS (Thermal Protection System) tiles and replaced one with a thinner tile to test how the loss of tiles would affect the ship.
Changes from the previous flight During Starship's third test flight, the booster was destroyed just before splashdown due to engine failures caused by filter blockage of liquid oxygen to the engines. The ship was destroyed during reentry, due to excessive roll rates caused by clogged roll control valves. As a result, modifications were made to Booster 11's oxygen tanks to improve propellant filtration capability, while hardware and software changes were implemented to improve
Raptor startup reliability. Additional roll control thrusters were added to the ship to improve attitude control redundancy. Several changes were spotted on Ship 29, including updates to the
TPS tile adhesive and layout. B11 received upgrades such as reinforcements of tanks and additions to improve rigidity and durability. The largest horizontal tanks in the orbital tank farm were made operational, supplementing the older vertical tanks that were being retired. Suborbital Pad B was decommissioned in May 2024, and vehicle testing operations were moved to
Massey's Test Site to make room for the construction of
Orbital Launch Mount B. ==Flight==