What Is a Rapid Unscheduled Disassembly?

It doesn’t take a degree in aerospace engineering to know that, ideally, rockets aren’t supposed to blow up.

So to those who aren’t engineers, the explosion of SpaceX’s Starship rocket on Thursday might have looked like a disaster — not the kind of result that should have prompted celebration from the SpaceX founder Elon Musk and his employees, who cheered what they considered a major success.

Casual space watchers were further amused by the company describing the result of the mission on Twitter with cosmic levels of euphemism. SpaceX called it “a rapid unscheduled disassembly” — or, put another way, an explosion.

But SpaceX wasn’t necessarily expecting the rocket — the most powerful and one of the most complex to ever fly — to actually emerge unscathed. Though it fell short of its most ambitious goal of gathering enough speed to reach orbit and then re-enter the atmosphere, it did claim other successes by flying for four minutes and getting well clear of the launchpad.

That was enough for employees at SpaceX headquarters to cheer the performance — one employee sprayed a bottle of champagne on colleagues — and for Bill Nelson, the NASA administrator, to congratulate the company.

Daniel Dumbacher, executive director of the American Institute of Aeronautics and Astronautics, said that SpaceX is accustomed to airing both its successes and failures, like it did when it first tried to land Falcon 9, the rocket that is its current workhorse. Many of those attempts ended unsuccessfully.

“They put them out there for everybody to see,” Mr. Dumbacher said. “And that’s great. In fact, I applaud them for that because it demonstrated how hard some of this stuff is.”

Big NASA programs like the Space Launch System that the government agency used for a launch to the moon in November are generally not afforded the same luxury of explode-as-you-learn. There tends to be much more testing and analysis on the ground — which slows development and increases costs — to avoid embarrassing public failures.

“Government programs are not allowed to operate that way because of that, because of the way we have all the stakeholders being able to watch over and tell you no,” Mr. Dumbacher said.

Even as SpaceX cheekily acknowledged the explosive end to the flight, it embraced it as a useful result.

“With a test like this, success comes from what we learn, and today’s test will help us improve Starship’s reliability as SpaceX seeks to make life multi-planetary,” the company wrote on Twitter.