The largest rocket ever built exploded over the Gulf of Mexico, minutes after its launch from a SpaceX facility on 20 April.

Starship SpaceX

Source: Twitter/SpaceX

SpaceX’s Starship heavy-lift rocket system undergoing fuelling and final tests before launch on 20 April

American manufacturer and launch provider SpaceX was conducting a test flight of its Starship system – a heavy-lift rocket and reusable flight vehicle designed to ferry crew and cargo beyond Earth’s orbit – from its base near Brownsville, Texas.

“Starship experienced a rapid, unscheduled disassembly before stage separation,” SpaceX said roughly 30min after the space vehicle’s launch. Live video of the test flight indicated the Starship assembly exploded some 4min following take-off, at an altitude of around 95,000ft.

Shortly after the incident, SpaceX chief executive Elon Musk congratulated the Starship team on an “exciting launch”.

“[We] learned a lot for the next test launch in a few months,” Musk tweeted.

The outcome was not necessarily a surprise to SpaceX or Musk, who had earlier estimated the chance of a successful mission at 50%. The goal of the flight had been to reach an altitude of 770,880ft, with the vehicle nearly circling the Earth and splashing down off the coast of Hawaii.

The privately developed heavy-lift rocket system is the most-power launch platform ever built. At 120m (394ft) in height, it towers over even the Boeing Saturn V rocket system that powered NASA’s Apollo lunar missions.

SpaceX says it designed Starship with capability to reach the moon, but also Mars and deep space beyond. The two-part launch system boasts a payload of 150,000kg (330,693lb) in its reusable configuration, and 250,000kg in expendable mode.

In November, NASA said it expanded a contract with SpaceX to develop Starship into a human landing system. The company is now scheduled to provide two crewed and one uncrewed lunar-landing demonstrations before 2027.

Those flights will occur under NASA’s Artemis III and IV missions.

“With multiple planned landers, from SpaceX and future partners, NASA will be better positioned to accomplish the missions of tomorrow: conducting more science on the surface of the Moon than ever before and preparing for crewed missions to Mars,” said NASA administrator Bill Nelson in November.

Starship SN15 High-Altitude Flight Test

Source: SpaceX

A Starship prototype without a Super Heavy rocket booster launches during a high-altitude test flight

NASA is also developing its Space Launch System, portions of which are being built by major US aerospace manufacturers including Boeing, Lockheed Martin, Northrop Grumman and Aerojet Rocketdyne. Boeing is the prime contractor.

SpaceX’s Starship system consists of two sections: the SpaceX Super Heavy first-stage rocket and the Starship vehicle itself. The 20 April test was the first test flight of the fully integrated Starship system – with both the flight vehicle and Super Heavy Rocket lifting off together.

The 20 April explosion was not the first for the Starship programme. In 2021, two Starship launch vehicle prototypes detonated catastrophically on separate flights.

In February 2021, a Starship launched without a first-stage rocket and flew under its own power for 6min. The vehicle crashed near a landing pad while attempting to descend under its own power.

A March 2021 test was more successful, with a separate Starship airframe achieving what SpaceX calls “controlled aerodynamic descent” after reaching an altitude of 33,000ft. However, an explosion from the craft’s lower section several minutes after touchdown blew that Starship off its landing pad, destroying the vessel.

In both cases, the flight vehicle launched without a Super Heavy rocket.

The Super Heavy rocket is powered by 33 SpaceX Raptor engines, which burn sub-cooled liquid methane and liquid oxygen. The reusable system delivers 16,733,085lb (74,432kN)-thrust.

The type is designed to return to Earth following separation, and to land upright at its launch site – similarly to SpaceX’s Falcon 9 and Falcon Heavy rockets, which commonly launch satellite payloads.

Falcon Heavy produces about 5,000,000lb-thrust – roughly one-third of Super Heavy’s thrust and about the same as generated by 18 Boeing 747 jets operating at full thrust.

The second portion of Starship – the Starship flight vehicle itself, which carries the system’s payload – adds an additional 3,306,700lb-thrust.

In addition to astronaut and cargo transport, SpaceX envisions its Starship system as eventually offering point-to-point transport between any locations on earth within 1h.