STARBASE, TEXAS — SpaceX canceled the Starship Flight 13 launch attempt on Thursday after the countdown clock reached zero. The launch had been scheduled for 5:45 pm local time (6:45 pm EDT; 22:45 UTC) from Starbase in South Texas.

Flight computers triggered an automatic abort during the Super Heavy booster’s engine startup sequence. A graphic on SpaceX’s live video stream indicated that four of the Heavy booster's 33 engines failed to ignite. Elon Musk stated, "Some of the engines didn’t start, triggering an automatic launch abort."

More than 11.5 million pounds of liquid methane and liquid oxygen had been loaded into the rocket before the abort. Engineers began preparations to drain the rocket’s propellant tanks following the abort. Ground teams will replace two of the Raptor engines on the Heavy booster, according to Musk.

The Heavy booster is equipped with 33 methane-fueled Raptor engines. This mission is the 13th full-scale Starship launch and the second to use the Raptor 3 engine on the Starship Version 3 rocket. The Starship V3 rocket and Raptor 3 engine debuted on a test flight in May.

During the May flight, slight differences in engine startup caused the Heavy booster to flip approximately 90 degrees off course during stage separation. The Federal Aviation Administration identified heat effects on propulsion system components and erroneous engine alarm system settings as the probable root causes of the Heavy booster failure in May. SpaceX modified the engine startup sequence for Flight 13 to be more robust to timing variability and improve flip reliability.

The payload for Flight 13 includes 20 Starlink V3 satellites. Six of the Starlink V3 satellites are equipped with cameras to photograph the exterior of the Starship spacecraft. The Starlink V3 satellites are designed to connect with the larger Starlink constellation via high-capacity lasers.

Starlink V3 satellites will burn up in the atmosphere approximately 20 minutes after deployment. Engineers will attempt to establish laser communication links between the Starlink V3 satellites and other spacecraft in low-Earth orbit. Starlink satellites will attempt to connect with ground stations in South Africa during the flight.

The Heavy booster aims to perform a controlled splashdown in the Gulf of Mexico. The Starship upper stage targets a controlled splashdown northwest of Australia. SpaceX is an American spaceflight and AI company.

SpaceX was established in 2002. NASA has selected Starship as a lunar lander for future Artemis missions. Musk said the most probable launch timing is early next week.

The abort demonstrates the technical challenges associated with the complex engine startup sequence of the Heavy booster. The vehicle carries 33 engines, and the failure of four to ignite prevented the launch from proceeding. This incident follows modifications made to the startup sequence after a previous flight experienced orientation issues during stage separation.

The mission carries a payload of Starlink V3 satellites intended for technology demonstrations, including exterior photography and laser communication tests. These tests support the broader development of the Starship system, which NASA has selected for future lunar missions. The scrub delays the next opportunity to demonstrate these capabilities until engineers complete repairs and prepare for the next attempt.