Diving on land: the Chinese rocket ready to return | Space News

The remains of China’s largest rocket, launched last week, are expected to re-enter the atmosphere in the coming hours, according to tracking centers in Europe and the United States.

The 18-ton main segment of the Long March-5B rocket that launched the first module of China’s new space station into Earth orbit on April 29 is now in freefall and experts said it was hard to say precisely where and when he would leave. enter the atmosphere.

China’s Foreign Ministry said on Friday that most of the debris would burn in the re-entry and was very unlikely to cause damage.

“The probability of causing damage … on the ground is extremely low,” Chinese Foreign Ministry spokesman Wang Wenbin told reporters.

The US Space Command estimated that the re-entry would take place on Sunday at 2:11 GMT, plus or minus an hour, while the Center for Orbital Reentry and Debris Studies (CORDS) of Aerospace Corporation, an American space research and development center funded by the federal government updated its two-hour forecast on either side of 03:02 GMT with the rocket returning over the Pacific.

EU Space Surveillance and Tracking (EU SST) said its latest prediction of when the Long March 5B rocket body reentry was 139 minutes on either side of 02:32 GMT on Sunday.

EU SST said the statistical probability of a ground impact in a populated area is “low”, but noted that the uncontrolled nature of the object made predictions uncertain.

Space-Track, reporting data collected by US Space Command, estimated that the debris would reentry over the Mediterranean basin.

Visitors walk through a mock-up of China’s Tianhe space station at an exhibition on the development of Chinese space exploration last month [Tingshu Wang/Reuters]

Traveling at a speed of about 13.7 km (4.8 miles) per second, a difference of just one minute in re-entry time translates into hundreds of miles of difference on the ground.

“It’s hard to predict and not an exact measurement,” Space-Track wrote on Twitter.

The Long March 5B – including a central stage and four boosters – took off from the Chinese island of Hainan on April 29 with the Tianhe unmanned module, which contains what will become living quarters on a permanent Chinese space station.

The rocket should be followed by 10 more missions to complete the station.

Most experts believe the risk to people is low.

“Given the size of the object, there will necessarily be large pieces left,” said Florent Delefie, astronomer at the Paris-PSL Observatory.

“The chances of debris landing on an inhabited area are minimal, probably one in a million.”

In May 2020, parts of the first Long March 5B fell on Côte d’Ivoire, damaging several buildings. No injuries were reported.

Debris from Chinese rocket launches is not uncommon in China. In late April, authorities in Shiyan City, Hubei Province, sent a notice to residents of the surrounding county to prepare for the evacuation, as some parts were to land in the area.

“The re-entry of the 5B long march is unusual because upon launch, the first stage of the rocket reached orbital speed instead of falling into range as is common practice,” the aerospace company said in an article. blog.

“The empty rocket body is now in an elliptical orbit around Earth where it is dragged into an uncontrolled reentry.”

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 return to Earth, with experts estimating its dry mass at around 18 to 22 tons.

The main stage of the first Long March 5B that returned to Earth last year weighed nearly 20 tons, overtaken only by debris from Space Shuttle Columbia in 2003, from the Soviet Union’s Salyut 7 space station in 1991 and the NASA Skylab in 1979.

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