Chinese rocket expected to crash into Earth this weekend

The Long March 5B rocket, which is about 100 feet tall and weighs 22 tons, is expected to hit the Earth’s atmosphere “around May 8,” according to a statement from Defense Department spokesman Mike Howard, who said the US space command track the missile trajectory.

The rocket’s “exact entry point into the Earth’s atmosphere” cannot be determined for hours after re-entry, Howard said, but the 18th Space Control Squadron provides daily updates on the rocket’s location through the Space Track website.

The good news is that debris falling towards Earth – while annoying – generally poses very little threat to personal safety.

“The risk of harm being done or of hitting someone is pretty small – not negligible, it could happen – but the risk that it will hit you is incredibly small. And so I wouldn’t lose a second of sleep. Jonathan McDowell, Astrophysicists at Harvard University’s Astrophysics Center, CNN told CNN this week.

The European Space Agency has predicted a “risk zone” to encompass “every part of the earth’s surface between approximately 41.5 N and 41.5 S latitude” – practically all of America south of New York, all of Africa and Australia, parts of Asia south of Japan and Europe’s Spain, Portugal, Italy and Greece.

This enormous range is due in part to the speed of the missile – even minor changes in circumstances can drastically alter its trajectory.

“We expect it to happen again sometime between May 8th and May 10th, and in that two-day period it will go around the world 30 times,” said McDowell.

“That thing travels at about 18,000 mph. So if you go an hour guessing when it’s going to come down, you’re 18,000 miles to tell where.”

Still, the ocean remains the safest bet as to where the debris will end up, he said, just because it takes up most of the earth’s surface. “If you want to bet on where on earth something will land, bet on the Pacific because the Pacific is most of the world. It’s that simple,” said McDowell.

The rocket launched a piece of the new Chinese space station into orbit on April 29, but then sped uncontrollably through space until Earth’s gravity began to pull it back to the ground.

This approach is a break with what McDowell calls “best practice” compared to what other space agencies do.

“Norms have been set,” he said. “There is no international law or rule – nothing specific – but the practice in countries around the world has been, ‘Yes, for the bigger missiles we don’t leave our junk in orbit like that.’ “”

Despite recent efforts to better regulate and mitigate space debris, Earth’s orbit is littered with hundreds of thousands of uncontrolled debris, most of which are less than four inches. Objects are constantly falling out of orbit, although most of them burn in the Earth’s atmosphere before they have any impact on the surface.

CNN’s Jackie Wattles contributed to this report.