SpaceX’s colossal Starship rocket and Super Heavy booster are poised to return to action Tuesday evening after the company wrapped up its investigation into the 400-foot-tall vehicle’s eighth test flight in March. Starship exploded during both that mission and Flight 7 in January.
The FAA issued a vehicle return to flight determination for Starship on Friday, clearing the path for Flight 9 — its third in an upgraded Block 2 configuration and first to feature a previously flown Super Heavy booster. Unlike previous flights, SpaceX will not attempt to catch and return the reusable booster to the launch pad, though it will aim for a few new feats.
“Developmental testing by definition is unpredictable,” SpaceX said in a preflight update. “But by putting hardware in a flight environment as frequently as possible, we’re able to quickly learn and execute design changes as we seek to bring Starship online as a fully and rapidly reusable vehicle.”
Following the launch, SpaceX CEO Elon Musk is expected to host a talk on social media platform X called “The Road to Making Life Multiplanetary,” alluding to Musk’s ambitions to land humans on Mars.
Aiming higher
Flight 7 marked the debut of Starship’s Block 2 variant, which features larger propellant tanks, greater payload capacity, and upgraded flaps and heat shield compared to the previous iteration. If all goes to plan, Flight 9 could be the first successful test of the configuration.
The mission is expected to lift off from SpaceX’s Starbase facility in Texas at 7:30 p.m. EDT on Tuesday, with a backup window scheduled for the same time on Wednesday.
Flight 9 will feature the first reflown Super Heavy booster, caught by a pair of giant metal chopsticks at the end of Flight 7 and refurbished for this mission. Reuse is one of the key selling points for both stages of the vehicle, as it reduces launch costs and downtime. A few components have been replaced, but the “large majority” of the booster — including 29 of 33 Raptor engines — will be flight-proven.
SpaceX successfully achieved booster catches on three of Starship’s past four test flights. It will not attempt one Tuesday — rather, Super Heavy will splash down off the coast of Florida in order for SpaceX to attempt a series of experiments.
After separating from Starship, the booster will “flip” its course in a known direction. That direction was randomized on previous flights, which required extra reserve propellant. The booster will also descend at a higher angle of attack, intended to increase drag, lower speed, and burn less propellant. During the landing burn, one of three center engines will be disabled to gauge how a backup engine could perform the maneuver.
Flight 9 will also attempt Starship’s first payload deployment on orbit: eight Starlink satellite simulators that will burn up upon reentry. Later, it will relight a single engine in space, a feat achieved on previous attempts.
It further aims to enable the eventual catch and return of Starship — a critical capability as SpaceX ramps up from five to 25 launches per year with recent FAA approval.
Engineers removed heat shield tiles to test vulnerable areas during reentry — some were replaced with alternative materials designed to better protect the vehicle. They also smoothed out the tile line to address “hot spots” encountered during Flight 6. The reentry profile is designed to stress the rear flaps and test the thermal and structural performance of catch fittings installed on the sides of the rocket.
Back-to-back mishaps have set Starship back at a time when SpaceX is trying to ramp up its launch cadence. The firm is developing a human landing system (HLS) variant of the vehicle to land NASA astronauts on the moon during the Artemis 3 mission, scheduled for mid-2027. Before then, it will need to complete several key milestones, including an uncrewed lunar landing demonstration.
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FAA approval to increase annual launches at Starbase should help. Beyond Texas, SpaceX is also building facilities at Kennedy Space Center in Florida — where it launches its prolific Falcon 9 rocket — to serve as a potential second launch site. It will need to produce an environmental impact statement before the expansion is approved.
To use its new privileges, though, SpaceX must avoid future mishaps, which can result in groundings stretching for weeks or months.
Wider berth
The launch failures of of Flights 7 and 8 disrupted air travel as debris threatened to fall through air corridors. In response, the FAA nearly doubled the aircraft hazard area (AHA) for Flight 9 to approximately 1,600 nm, extending eastward from the launch site through Florida and now including the Bahamas and Turks and Caicos Islands “due to vehicle reliability,” it said. The agency required SpaceX to schedule the launch window — which opens at 7:30 p.m. EDT — outside “peak transit periods.”
“The Starship vehicle mishaps from Flights 7 and 8 caused a greater probability of failure of the vehicle and, therefore, a larger AHA,” the FAA said in an environmental assessment noting the airspace closures. “These AHAs define the temporarily closed airspace that would be established and published through a NOTAM prior to the launch/reentry.”
The FAA warned the expanded precautions could delay more than 175 flights, nearly all on international connecting routes, by an average of 40 minutes — but they could stretch up to two hours. General aviation operations would similarly be impacted. The FAA told FLYING that 171 departures were delayed by an average of 28 minutes during Flight 8. Twenty-eight flights were diverted, and another 40 were placed in holding patterns.
Additional information on airspace closures can be found in the FAA’s current operations plan advisory.
According to SpaceX, the mishaps on Flight 7 and 8 happened around the same point in the mission timeline — but they did not have the same cause.
Both tests ended prematurely when Starship lost control and broke apart in the upper atmosphere. In its mishap report for Flight 8, SpaceX said the rocket likely fired its Autonomous Flight Safety System after its Raptor 2 engines shut down and communications were lost. The company traced the engine loss to a potential hardware failure in one of the center engines “that resulted in inadvertent propellant mixing and ignition.”
The Flight 7 mishap, by contrast, was caused by “stronger than anticipated vibrations during flight [that] led to increased stress on, and failure of, the hardware in the propulsion system.”
According to SpaceX, “the mitigations put in place after Starship’s seventh flight test to address harmonic response and flammability of the ship’s attic section worked as designed prior to the failure on Flight 8.”
After firing Raptors more than 100 times at its test facility in McGregor, Texas, the company made a few modifications for Flight 9 as well. Starship engines will receive a new nitrogen purge system, propellant drain system improvements, and “additional preload on key joints,” it said. Future missions will feature upgraded Raptor 3 engines that are designed to prevent a similar failure.
A version of this story first appeared on FLYING.
