China’s Tiangong-1 Expected to Crash to Earth Within Weeks - Gateway Gazette

China’s Tiangong-1 Expected to Crash to Earth Within Weeks

By Gateway Gazette

Mar 13

 

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AeroTime Staff

China’s first space station – the Tiangong-1, also known as “Heavenly Palace 1”, – is expected to come crashing down to Earth within weeks, experts say. Agencies around the world have been monitoring the spacecraft’s descent as the space station has been out of control since September 2016. Scientist have not been able to predict exactly where and when the module will re-enter the Earth’s atmosphere, but forecasts indicate Europe, the U.S., Australia and New Zealand.

According to the March 7, 2018, estimates by the Aerospace Corporation – a federally funded research and development center in the U.S. – Tiangong-1 will re-enter the Earth’s atmosphere around April 3, 2018, give or take a week. Also, as of January 12, 2018, The European Space Agency (ESA) predicted the module will come down in the window of March 29, 2018, to April 9, 2018. All of the above predictions assume an uncontrolled re-entry.

According to the ESA, the spacecraft is now at an altitude of less than 300 km (186 miles) in an orbit that is decaying, forcing it to make an uncontrolled re-entry into the atmosphere, The Daily Mailreports. The head of ESA’s Space Debris Office, Holger Krag, was reported saying that there are large uncertainties in predicting the date, time and geographic footprint of the re-entry. “Even shortly before re-entry, only a very large time and geographical window can be estimated,” he said.

According to data provided by Aerospace, The Tiangong-1 was launched into orbit on September 30, 2011, aboard a Long March 2F/G rocket from Jiuquan Satellite Launch Center in China. It is the first space laboratory built and launched by China. With the design life of two years, the space station was set to carry out a series of docking and orbit experiments.

The Tiangong-1, with the operating life span of two years, was designed to be a manned lab and an experimental demonstration for the larger, multiple module Tiangong Station. The space station consists of two modules: a habitable experimental module and a resources module. The first Chinese orbital docking occurred between Tiangong-1 and an unmanned Shenzhou spacecraft on November 2, 2011.

There had been two manned missions to the Tiangong-1: Shenzhou 9, launched on June 16, 2012, with three astronauts, and Shenzhou 10, launched on June 11, 2013, also with three astronauts. The Shenzhou 9 had China’s first female astronaut Liu Yang aboard, and the Shenzhou 10 completed the first Chinese orbital maintenance. It was the last manned mission which departed from the Tiangong-1 in June 2013.

On March 21, 2016, the Chinese news agency Xinhuanet reported that telemetry services with the Tiangong-1 had ceased, stating that “After an operational orbit of 1,630 days, China’s first space lab Tiangong-1 terminated its data service.“ Adding that “The functions of the space laboratory and target orbiter have been disabled after an extended service period of about two and a half years.“

On September 14, 2016, Xinhuanet broke the news that the space station is set to re-enter the Earth‘s atmosphere in late 2017, despite previous reports stating that the orbiter would descend to Earth gradually over several months and eventually burn up in the atmosphere.

On December 8, 2017, China updated its forecasts for the space station’s re-entry by an announcement to the United Nation’s (UN) Committee on Peaceful Uses of Outer Space, stating that the re-entry is expected between the first 1o days of February and the last 10 days of March 2018.

On January 8, 2018, Reuters reported a top engineer at the China Aerospace Science and Technology Corporation , Zhu Congpeng, saying that the Tiangong-1 is not out of control and does not pose a safety or environmental threat.

“We have been continuously monitoring Tiangong-1 and expect to allow it to fall within the first half of this year,” Zhu was cited saying. Adding that, “It will burn up on entering the atmosphere and the remaining wreckage will fall into a designated area of the sea, without endangering the surface.”

According to Reuters, although the Tiangong-1 was originally planned to be decommissioned in 2013, the length of its mission was repeatedly extended. And, as previously mentioned, the re-entry was delayed in September 2017, apparently to ensure that the wreckage would fall into the South Pacific Ocean. This delay had led some experts to suspect the space laboratory may be out of control, although it has not yet been confirmed officially by the Chinese.

The California-based Aerospace Corporation says it is much easier to predict an accurate reentry time rather than an accurate reentry location. However, based on Tiangong-1 inclination, the non-profit organization maintains that “we can confidently say that this object will reenter somewhere between 43° North and 43° South latitudes.”

Much of the spacecraft is expected to burn up in the atmosphere upon re-entry. But Aerospace says it is expected that there will be many pieces re-entering together, due to the relatively large size of the object, some of which may survive re-entry and fall to Earth. However, it is highly unlikely that this debris will harm any person or significantly damage any property. What is of primary concern, is that “there may be a highly toxic and corrosive substance called hydrazine on board the spacecraft that could survive the re-entry.”

Jonathan McDowell, an astrophysicist from Harvard University, said fragments from a similar-sized rocket re-entered the atmosphere and landed in Peru in January, 2018. “Every couple of years something like this happens, but Tiangong-1 is big and dense so we need to keep an eye on it,” he told The Guardian.

According to McDowell, Tiangong-1’s descent had been speeding up in recent months and it was now falling by about 6 km (3.7 miles) a week, compared with 1.5 km (0.9 miles) in October, 2017. Another reason why it is difficult to predict when the spacecraft will land, he says, is its speed which was affected by the constantly changing “weather” in space. “It is only in the final week or so that we are going to be able to start speaking about it with more confidence,” McDowell said.

Whatever the outcome, this will not be the largest man made object to ever re-enter from space. As Aerospace writes, the largest orbject to re-enter the Earth’s atmosphere was the Mir space station at 120 tons (compared to the 8.5-ton Tiangong-1). The Mir space station re-entered the atmosphere on March 23, 2001.

The Guardian also reminds of Nasa’s 77-ton Skylab space station which came down to Earth in an almost uncontrolled descent in 1979, some large pieces of it landing outside Perth in Western Australia. Over a decade later, the Soviet Union’s 20-ton Salyut 7 space station crashed to Earth while still docked to another 20-ton spacecraft called Cosmos 1686 in 1991. They broke up over Argentina, scattering debris over the town of Capitán Bermúdez.

Tiangong-1 space laboratory had originally been a symbol of China’s ambitious bid to become a space superpower. Advancing China’s space program has been a priority for President Xi Jinping, who has called the nation to become a global space power with both advanced civilian space flight and capabilities that would strengthen national security, Reuters explains.

The Chinese news agency Xinhuanet has previously praised the Tiangong-1 saying it had greatly contributed to the Chinese space program. It also stated that the aim of China’s multi-billion-dollar space program is to put a permanent manned space station into service by around 2020.

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