4 things to know about the AWOL Tiangong-1 satellite

6 Mar 2018

Image: Vadim Sadovski/Shutterstock

China’s AWOL satellite Tiangong-1 is expected to burn up in our atmosphere very soon, but what do we have to know, or even fear?

Last October, China confirmed that its ‘heavenly palace’ Tiangong-1 satellite was no longer within its control and would be crashing down to Earth in the coming months.

As this is now a matter of weeks away, according to The Guardian, a number of questions need to be answered as space agencies ponder what the ramifications might be from a giant piece of space debris falling to Earth.

Future Human

When will it re-enter?

While the window of re-entry has been scaled down to just a few weeks, it’s still hard to predict when exactly it will reach Earth’s atmosphere.

The Aerospace Corporation in the US predicts that it could come down during either side of the first week of April, while the European Space Agency (ESA) predicts a wider and earlier range from 24 March to 19 April.

The new estimates come after readings of Tiangong-1’s descent showed it had been speeding up in recent months at a rate of 6km a week, compared with 1.5km back in October.

“It is only in the final week or so that we are going to be able to start speaking about it with more confidence,” said Jonathan McDowell, an astrophysicist from Harvard University.

Where will it re-enter?

Again, this is a tricky question, as estimates so far suggest the space station will re-enter somewhere between the latitudes of 43 degrees north and south.

This puts many areas of the world in its path, including the northern part of its native China, central Italy, the northern US and even parts of South America and Africa.

Despite its increased falling speed towards Earth, the speed could change again if other variables are to enter in the meantime, such as major space weather events.

Will fragments fall on Earth?

Questions have been asked as to whether fragments of the space station could make it through Earth’s atmosphere.

The space station, launched in 2011, weighed up to 8.5 tonnes when in operation and, with some of the largest components weighing as many as 100kg, there is a chance some could fall to Earth.

The Aerospace Corporation said there is “a chance that a small amount of debris” could make it through, and that if this were to happen, it would be limited to a region a few hundred kilometres across.

McDowell, however, said it is more than likely that we’ll only know that pieces survived re-entry afterwards.

Is there anything we should be worried about?

Fears of a potential disaster caused by the wreckage of Tiangong-1 have been dampened by those following the craft, with The Aerospace Corporation describing it as highly unlikely.

“When considering the worst-case location … the probability that a specific person (ie you) will be struck by Tiangong-1 debris is about 1m times smaller than the odds of winning the Powerball jackpot,” the company said.

“In the history of spaceflight, no known person has ever been harmed by re-entering space debris. Only one person has ever been recorded as being hit by a piece of space debris and, fortunately, she was not injured.”

However, it did warn that the space station might be carrying a dangerous substance.

“Potentially, there may be a highly toxic and corrosive substance called hydrazine on board the spacecraft that could survive re-entry,” it said.

“For your safety, do not touch any debris you may find on the ground nor inhale vapours it may emit.”

Colm Gorey was a senior journalist with Silicon Republic