SpaceX Starship Flight 10

SpaceX’s powerful Starship rocket is nearing a return to action following an explosion on the company’s test stand in Texas and anomalies during three consecutive test flights.

The FAA on Friday closed its mishap investigation into Starship Flight 9, during which the rocket reached orbit for the first time in 2025 but failed to hit its test objectives. That opens the door for another launch, which SpaceX is targeting for no earlier than 7:30 p.m. ET on Sunday.

The regulator suspended more than 70 air routes ahead of Flight 9 due to issues experienced during Starship’s ascent burn on Flight 7 in January and Flight 8 in March. On both occasions, the rocket exploded and disrupted air travel.

SpaceX had aimed to return to action in late June. But the vehicle for Flight 10, Ship 36, erupted into flames during an engine static fire test.

With the FAA’s green light, it appears SpaceX has a handle on these issues. The company on Friday offered an explanation of what went wrong—and how it plans to avoid a repeat mishap.

SpaceX investigates

Starship Flight 9 got off to a promising start, completing the ascent burn where previous test flights failed. But issues became evident minutes into the coast phase, when the vehicle’s payload door failed to open and release a group of Starlink satellite demonstrators. By the reentry phase, Starship had lost attitude control, ultimately tumbling into the Indian Ocean.

In a postlaunch update, SpaceX CEO Elon Musk speculated that “leaks caused loss of main tank pressure during the coast and re-entry phase,” resulting in the loss of control. As it turns out, Musk was not far off.

SpaceX traced the anomaly to a damaged pressurization system diffuser on the main fuel tank that was not caught during preflight analysis. But using Flight 9 conditions, the company managed to recreate the damage during testing at its McGregor, Texas, facility.

The damaged diffuser likely set off a chain of events that derailed the mission. Sensors in Starship’s nosecone detected rising methane levels about three minutes into the ascent burn, increasing pressure in the nosecone. This caused an attitude error during nosecone venting, which was cut off by an automatic fault system after the pressure rose to an unstable level.

The added pressure indirectly prevented Starship’s payload door from opening, causing it to abandon the Starlink deployment. Later, reaction control system (RCS) thrusters restored some attitude control, allowing venting to continue. But liquid methane propellant entered the nose cone and caused temperatures to plummet, forcing the vehicle to skip an in-space engine relight and vent all propellant.

The rocket reentered the atmosphere on an “off-nominal attitude,” and communications and telemetry were lost soon after.

“There were no autonomous flight safety system mission rule violations or initiation of the flight termination system,” SpaceX said.

The company said it redesigned the faulty diffuser system to create less stress on the structure. It also put the system through a “more rigorous qualification campaign” that entailed running it for 10 times longer than its expected lifespan, with no damage.

Flight 9 called for a series of reentry experiments designed to enable the eventual catch and return of Starship. But the vehicle never made it to that phase, and telemetry and communications were lost.

The test flight featured the first reflown Super Heavy booster, which SpaceX has caught three times. However, it too failed to complete its mission, exploding about 1 kilometer above the landing platform.

In order to test its durability, Super Heavy descended at a “significantly higher angle of attack than previous flights,” SpaceX said. The booster experienced “higher than expected” loads that exceeded the capacity of its fuel transfer tube, which failed, causing propellant mixing that created the explosion.

The company said subsequent flights with this version of Super Heavy will fly at a lower angle of attack.

SpaceX also made changes following the loss of Ship 36. The rocket experienced a “sudden energetic event” on the test stand in June, resulting in “complete loss” of the vehicle and damage to the surrounding area. Engineers had been loading it with cryogenic propellant ahead of a routine test.

The company attributed the anomaly to “undetectable or under screened” damage to a pressure vessel within the ship’s payload section, which stores nitrogen gas for its environmental control system.

Future flights will place less pressure on the vessel and require more rigorous preflight inspections, SpaceX said. The company also came up with a better method to screen for damage and is installing a protective cover that will help identify faults.

Despite the setbacks, SpaceX is turning its attention to Starship’s milestone 10th flight. Musk in May predicted that “launch cadence for next 3 flights will be faster, at approximately 1 every 3 to 4 weeks,” meaning it will need to make up some ground.

Starship’s tenth test flight

Starship Flight 10 will lift off from SpaceX’s Starbase launch pad in Texas no earlier than Sunday evening. Unlike previous test flights, it will not include a booster catch attempt—rather, SpaceX said the goal is to “continue to expand the operating envelope” for Starship and Super Heavy.

The booster will attempt a controlled flip maneuver first demonstrated on Flight 9. The maneuver saves fuel, allowing more propellant to be used during the ascent to support heavier payloads. But the primary objectives are scheduled for the landing burn.

SpaceX will disable one of Super Heavy’s three main center engines to test the performance of a backup engine. For the final phase of the burn, it will ignite only two center engines, hovering in place before dropping into the ocean.

Similar experiments are planned for Starship. The rocket will once again attempt its first payload deployment. But the focus will be on gathering data that could enable its eventual catch and return, akin to Super Heavy.

Engineers removed a “significant number” of heat shield tiles to gauge the performance of vulnerable areas. Some of these were replaced with metallic tiles, which will be tested as alternative materials. SpaceX will also evaluate the thermal and structural performance of catch fittings, as well as a section of tile that was modified after being identified as a “hot spot” during Flight 6.

“Starship’s reentry profile is designed to intentionally stress the structural limits of the upper stage’s rear flaps while at the point of maximum entry dynamic pressure,” SpaceX said.

Recent delays could impact SpaceX’s timeline of lunar and Martian ambitions. The company is developing a Starship human landing system (HLS) that will deliver NASA astronauts to the moon’s south pole on the Artemis 3 mission, scheduled for mid-2027. Fulfilling those contract obligations will require several more test flights.

Before Artemis 3, Musk aims to launch an uncrewed Starship to Mars. The SpaceX CEO in May said the company hopes to take advantage of a late 2026 window that will not reopen for about two years. Subsequent missions could be crewed, Musk said, to lay the early groundwork for a Martian colony.

SpaceX and its competitors’ efforts received a boost last week with a White House executive order that directs federal agencies to relax commercial spaceflight regulations. The order calls to eliminate or streamline environmental reviews that are required for obtaining a launch license, among other industry-friendly provisions.

The directive may be significant for SpaceX, which is building a planned launch site called Gigabase at NASA’s Kennedy Space Center in Florida. So far, all Starships have launched from Texas.

SpaceX said Flight 10 will be the second-to-last flight for the current iteration of Starship and Super Heavy, Block 2. An upgraded Block 3, which could debut as early as this year, will be taller and more powerful, with a new docking system for on-orbit refueling.

Editor’s note: This story first appeared on FLYING.