The Long March 5B lifted off on July 24, carrying a new module toward China's under-construction Tiangong space station. Unlike the core stages of most rockets, which are steered to a safe disposal shortly after launch or land softly for future reuse, the Long March 5B reached orbit along with its payload. And it stayed up — as a big, fast-moving piece of space junk — until atmospheric drag brought it down in an unpredictable and uncontrolled fashion.

Mission managers didn't screw anything up; this end-of-life scenario is built into the Long March 5B's design, to the consternation of exploration advocates and much of the broader spaceflight community. This disposal strategy is reckless, critics say, given that the big rocket doesn't burn up completely upon reentry.

Indeed, 5.5 tons to 9.9 tons (5 to 9 metric tons) of the Long March 5B likely survived all the way to the ground today, experts with The Aerospace Corporation's Center for Orbital Reentry and Debris Studies have estimated (opens in new tab).

And it's possible that falling rocket chunks caused some injuries or infrastructure damage today, given where the Long March 5B reentered. One observer appeared to capture the rocket's breakup from Kuching, in the Malaysian state of Sarawak, for example, posting video of the dramatic event on Twitter (opens in new tab).

"The video from Kuching implies it was high in the atmosphere at that time — any debris would land hundreds of km further along track, near Sibu, Bintulu or even Brunei," astrophysicist and satellite tracker Jonathan McDowell, of the Harvard-Smithsonian Center for Astrophysics, said via Twitter today (opens in new tab). It's "unlikely but not impossible" that one or more chunks hit a population center, he added in another tweet (opens in new tab).

Chinese space officials, for their part, said (opens in new tab) the rocket body reentered at 119.0 degrees east longitude and 9.1 degrees north latitude. That location is over open ocean, just off the coast of Palawan Island, which is part of the Philippines.

We'll have to wait a while to see exactly where the rocket debris came down. But the fact that the crash occurred at all does not reflect well on China and its spaceflight program, experts say.

"What really should have happened is, there should have been some fuel left on board for this to be a controlled reentry," Darren McKnight, a senior technical fellow at the California-based tracking company LeoLabs, said Thursday (July 28) during a Long March 5B reentry discussion that The Aerospace Corporation livestreamed on Twitter. "That would be the responsible thing to do."

NASA Administrator Bill Nelson voiced similar sentiments, calling out China in a statement issued today (opens in new tab) shortly after the reentry.

"The People’s Republic of China (PRC) did not share specific trajectory information as their Long March 5B rocket fell back to Earth," Nelson said.

"All spacefaring nations should follow established best practices, and do their part to share this type of information in advance to allow reliable predictions of potential debris impact risk, especially for heavy-lift vehicles, like the Long March 5B, which carry a significant risk of loss of life and property," he added. "Doing so is critical to the responsible use of space and to ensure the safety of people here on Earth."