Starship flight test 1 was the maiden flight of the integrated SpaceX Starship launch vehicle. SpaceX performed the flight test on April 20, 2023. The prototype vehicle was destroyed less than four minutes after lifting off from the SpaceX Starbase in Boca Chica, Texas. The vehicle became the most powerful rocket ever flown, breaking the half-century-old record held by the Soviet Union's N1 rocket. The launch was the first "integrated flight test," meaning it was the first time that the Super Heavy booster and the Starship spacecraft flew together as a fully integrated Starship launch vehicle.

The launch was part of SpaceX's Starship development program, which follows an iterative and incremental approach involving frequent, and often destructive, test flights of prototype vehicles. Before the launch, SpaceX officials said they would measure the mission's success "by how much we can learn" and that various planned mission events "are not required for a successful test". The flight was generally regarded as having furthered Starship's development, and a variety of public officials congratulated SpaceX, including NASA administrator Bill Nelson and European Space Agency Director General Josef Aschbacher.

It was planned for the Starship spacecraft to complete nearly one orbit around the Earth before reentering the atmosphere, performing a controlled descent and splashing down in the Pacific Ocean near Hawaii. The Super Heavy booster was to have performed a similar landing in the Gulf of Mexico, about 20 mi (30 km) off the Texas coast about 8 minutes after liftoff.

The rocket lifted off at 13:33 UTC (8:33 am CDT, local time at the launch site) from SpaceX's private launch site near Boca Chica, Texas. The liftoff damaged the launch pad and its surrounding infrastructure, which SpaceX said was unexpected. Some debris spread into Boca Chica State Park. Three engines did not start or aborted before liftoff, and several others failed during the flight. The vehicle passed max q and entered supersonic flight, but, due to a lack of thrust or thrust vector control, no attempt was made at stage separation. After Starship began to lose altitude and tumble, the autonomous flight termination system (AFTS) on the vehicle activated, which took 40 seconds to destroy the vehicle, nearly 4 minutes into the flight.

After the test, the Federal Aviation Administration (FAA) grounded the launch program pending results of a standard “mishap investigation” overseen by the agency and performed by SpaceX. The FAA said that a return to flight would depend on the agency's determination that future launches would not affect public safety. In August 2023, SpaceX submitted to the FAA the 63 "corrective actions" that it would need to take before another Starship launch would be allowed. Dust scattered by the launch initially caused some health concerns, but was later found by a laboratory to be ordinary beach sand, not posing a health hazard.

A second flight test of the Starship vehicle occurred on November 18, 2023, seven months after its maiden flight. The launch did not repeat issues encountered on the first flight; the vehicle successfully performed stage separation using a new method, but both vehicles were lost thereafter.

Developed by SpaceX, Starship is a super heavy-lift launch vehicle, the largest and most powerful ever developed. Standing 121 m (397 ft) tall, it is projected to be able to carry 150 t (330,000 lb) of payload in a fully reusable configuration. Its 33 first-stage Raptor engines nominally generate more than 16,000,000 lbf (71 MN) of thrust. This is roughly twice that of NASA's Saturn V (7,750,000 lbf (34.5 MN)) which flew between 1967 and 1973; more than NASA's SLS, which produced 8,800,000 lbf (39 MN) of thrust at liftoff in 2022; and well above the 10,000,000 lbf (44 MN) of thrust from the 30 engines that powered the Soviet Union's N1 rocket between 1969 and 1972.

On its first orbital test flight, Starship broke the N1's half-century-old record for the most powerful rocket-stage ever launched.