Remnants of China’s largest rocket launched last week are expected to plunge back through the atmosphere late Saturday or early Sunday, the US federally funded space-focused research and development centre said. China’s foreign ministry said on Friday that most debris from the rocket will be burned up on re-entry and is highly unlikely to cause any harm after the US military said that what it called an uncontrolled re-entry was being tracked by US Space Command.

In a tweet sent on Friday evening in the United States, the Aerospace Corporation said that the latest prediction for the re-entry of the Long March 5B rocket body by its Centre for Orbital Re-entry and Debris Studies (CORDS) was for eight hours on either side of 0419 GMT on Sunday.

CORDS’ latest “informed prediction” of the rocket body’s re-entry location was given near the North Island of New Zealand, but it noted that re-entry was possible anywhere along paths covering large swathes of the globe.

The Long March 5B comprising one core stage and four boosters lifted off from China’s Hainan island on April 29 with the unmanned Tianhe module, which contains what will become living quarters on a permanent Chinese space station.

The Long March 5 family of rockets have been integral to China’s near-term space ambitions from the delivery of modules and crew of its planned space station to launches of exploratory probes to the moon and even Mars.

The Long March launched last week was the second deployment of the 5B variant since its maiden flight in May last year.

Harvard-based astrophysicist Jonathan McDowell previously told Reuters there is a chance that pieces of the rocket could come down over land, perhaps in a populated area, as in May 2020, when pieces from the first Long March 5B rained down on the Ivory Coast, damaging several buildings, though no injuries were reported.

Debris from Chinese rocket launches is not uncommon within China. In late April, authorities in the city of Shiyan, Hubei province, issued a notice to people in the surrounding county to prepare for evacuation as parts were expected to land in the area.

“The Long March 5B re-entry is unusual because, during launch, the first stage of the rocket reached orbital velocity instead of falling downrange as is common practice,” the Aerospace Corporation said in a blog post. “The empty rocket body is now in an elliptical orbit around Earth where it is being dragged towards an uncontrolled re-entry.

"The empty core stage has been losing altitude since last week, but the speed of its orbital decay remains uncertain due to unpredictable atmospheric variables.

It is one of the largest space debris to re-enter Earth, at 18 tonnes. The core stage of the first Long March 5B that returned to Earth last year weighed nearly 20 tonnes, surpassed only by debris from the Columbia space shuttle in 2003, the Soviet Union’s Salyut 7 space station in 1991, and NASA’s Skylab in 1979.

What is the size of the debris?
As per the reports by The Guardian, a large part of the debris that will crash back to Earth on Saturday, US time, is roughly 30 metres (100ft) long and weighs over 20,000 kg, making it one of the longest debris to ever fall on the earth.

When will the giant piece hit the earth?
One of the pieces from China’s largest rocket, the Long March 5B, is tumbling out of control in space and it is certainly something to worry about. The exact location of where this Chinese rocket will fall cannot be predicted, still, as per the media reports, the debris is expected to re-enter and crash between 1.30 PM UTC (7.30 PM IST) on 8 May and 7.30 PM UTC on 9 May (1.00 AM IST on 10 May).

Where will the Chinese rocket crash?
Determining the exact location is difficult for scientists, as of now. Although, it is expected that the crash will reportedly occur between latitudes 41.5 degrees north, which runs through North America, Southern Europe, and China, and 41.5 degrees south, which falls in S. America, Africa, Australia, and NZ, as its orbital inclination is 41.5 degrees.

What will happen when debris from this Chinese rocket hits the earth?
It"s a routine for every rocket stage to fall after a while, once its fuel is burnt and the altitude is reached. Though for most rockets it occurs immediately, some take time. Lower stages burn in the atmosphere while upper stages reach orbit, fire their engines after a while, and reenter the earth harmlessly over the ocean.

But China has been criticized for its habit of not planning the re-entry properly. In 2020 also, they launched another Long March 5B rocket which made an "out-of-control re-entry into the earth, damaging buildings in two villages that were situated in the Republic of Ivory Coast, in West Africa.

China"s first space station, Tiangong-1, crashed into the Pacific Ocean in 2016. In 2019, they performed a controlled re-entry of its second station, Tiangong-2, which ended up burning in the atmosphere over the Pacific Ocean.