Starship SN1 burst
A video feed capturing SpaceX's Starship SN1 vehicle bursting during a pressurization test late Feb. 28 at Boca Chica, Texas. Credit: Space Padre Isle

Updated 7:15 a.m. Eastern March 2 with comments from Elon Musk.

WASHINGTON — A second prototype of SpaceX’s Starship launch vehicle was destroyed in a pressurization test Feb. 28 at the company’s Boca Chica, Texas, facility.

Video from several observers showed the vehicle bursting at about 11 p.m. Eastern. The vehicle, without its nose cone or with any Raptor engines yet installed, was on a test stand being loaded with liquid nitrogen. The vehicle appeared to come apart near the bottom, sending the top section flying, with a second burst after that section hit the ground.

Photos the next day showed that little of the vehicle, known as Starship SN1, survived. There were no reports by local authorities of any injuries. SpaceX did not respond to a request for comment early Feb. 29 about the test, and company founder Elon Musk, who routinely has shared details about Starship development on Twitter, was initially silent about the incident.

Musk did tweet a video of the test early March 2. “So … how was your night?” he wrote. In subsequent tweets, he said workers were now focusing on the Starship SN2 vehicle under development to prepare it for similar pressurization tests.

The destruction of Starship SN1 is similar to the loss of another prototype, called Starship Mark 1, in November. That vehicle was also undergoing a pressurization test when a bulkhead failed, sending part of the vehicle flying into the air. SpaceX said that incident took place during a test to “pressurize systems to the max” and that the failure was not unexpected, nor was it “a serious setback.”

Musk, at a September event at Boca Chica, said that Starship Mark 1 would fly in one or two months, but the company said after the test incident that was not the case. “The decision had already been made to not fly this test article and the team is focused on the Mk3 builds, which are designed for orbit,” the company said. SpaceX later renamed Starship Mark 3 to Starship SN1.

SpaceX appeared to be preparing Starship SN1 for a static-fire test with at least one Raptor engine installed. “Starship SN1 tank preparing for Raptor attachment & static fire,” Musk tweeted Feb. 25. There were also notices to airmen (NOTAMs) related to test activity at the site, but it wasn’t clear if those notices covered any planned static fire tests or only the pressurization test.

That static test was to be followed by at least one suborbital test flight of the vehicle, where it would take off, fly to an altitude of 20 kilometers, and land back at Boca Chica. In a late December tweet, Musk said that flight would likely take place in two or three months.

SpaceX had yet to receive a launch license or experimental permit from the Federal Aviation Administration’s Office of Commercial Space Transportation for a suborbital test flight, but had filed two applications with the Federal Communications Commission for licenses needed for telemetry and vehicle radar operations for that mission. Both license applications requested a six-month period of operations starting in mid-March.

There had been speculation that Starship SN1 might only have been used for static-fire tests, with another prototype under construction, Starship SN2, used for test flights. The SN2 version features improved production and welding techniques.

“Designing a rocket is trivial,” Musk said in an on-stage interview Feb. 28 at the Air Force Association’s annual winter symposium, hours before the ill-fated pressurization test, discussing his philosophy regarding innovation. By contrast, “the hard part is making it, and making lots of them, and launching frequently.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...