HOUSTON — The first prototype of SpaceX’s next-generation launch system was damaged Nov. 20 during a tanking test, a setback the company claimed would not serious affect their development plans.

Video from several observers in the vicinity of SpaceX’s test site in Boca Chica, Texas, near Brownsville, showed a white plume erupt from the top of the Starship Mark 1 vehicle undergoing a pressurization test there at about 4:30 p.m. Eastern. That eruption blew off part of the bulkhead from that section of the vehicle, which could be seen falling back to the ground several seconds later.

The vehicle, not fully assembled at the time, was undergoing a series of tests that, at the time, most believed would lead to an initial suborbital flight of the vehicle in the near future. The vehicle remained standing and the extent of the damage, beyond the ejected bulkhead, was not immediately known.

“The purpose of today’s test was to pressurize systems to the max, so the outcome was not completely unexpected,” SpaceX said in a statement about two and a half hours after the event. “There were no injuries, nor is this a serious setback.”

At an event in Boca Chica Sept. 28, SpaceX showed off this initial prototype of what will eventually be the second stage of a heavy-lift reusable launch vehicle. At the time, SpaceX planned to start suborbital flight tests of the vehicle, to an altitude of about 20 kilometers, later this year.

“This thing is going to take off, fly to 65,000 feet, about 20 kilometers, and come back and land, in about one or two months,” Elon Musk, founder and chief executive of SpaceX, said at the event, with the fully assembled Starship Mark 1 as a backdrop.

However, SpaceX said in its statement that the Mark 1 vehicle would not fly after all, even before this test incident. “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.

At the September 28 event, Musk said the team at Boca Chica would start work in about a month on a second prototype, called Mark 3, which he estimated to be completed in about three months. That vehicle, he said, would be used for orbital flight tests.

Musk, in a tweet shortly after the incident, also said the company would move on to the Mark 3 vehicle. “This had some value as a manufacturing pathfinder,” he said of the Mark 1 version of Starship, “but [the] flight design is quite different.”

A separate SpaceX team in Florida is also working on Starship vehicles, starting with a prototype called Mark 2 that appeared to be nearing completion based on images from the site. SpaceX hasn’t disclosed plans for Mark 2, which previously was set to be transported to Cape Canaveral for testing.