How much of a threat to humanity is falling space junk

Over the weekend, debris from an out-of-control Chinese rocket crashed to Earth over the Indian and Pacific oceans.

There had been fears that pieces of the 23-tonne Long March 5B booster could come down over a populated area, but experts had said the probability of this was extremely low.

Nevertheless, NASA hit out at China by accusing Beijing of not sharing the ‘specific trajectory information’ needed to calculate where possible debris might fall. 

Elsewhere at the weekend, a 10ft (3m) piece of space junk – thought to be from one of Elon Musk’s spacecrafts – crashed into a farmer’s property in Australia at around 15,500mph (25,000km/h).

The object, believed to be part of the SpaceX Crew-1 craft, was found in a sheep paddock by a farmer living on a large property in the Snowy Mountains in New South Wales.

These events have sparked further questions about the threat of space debris to people on the ground, although experts insist it is still a very remote possibility that anyone would be hurt.

A recent study by scientists at the University of British Columbia in Vancouver warned there was a 10 per cent chance that an out-of-control rocket or spacecraft could kill someone within the next decade.  

Meanwhile, Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, told MailOnline that despite the increase in space debris in low-Earth orbit, this does not equate to more risk for humans.

The remnants of the Chinese rocket were caught on video as it disintegrated over Malaysia, before landing in the Indian Ocean on Saturday night

The video, taken by a Twitter user who initially thought it was a meteor, shows the craft racing across the sky before it burns in the atmosphere upon its re-entry

The video, taken by a Twitter user who initially thought it was a meteor, shows the craft racing across the sky before it burns in the atmosphere upon its re-entry

The 23-tonne core stage of China's Long March 5B-Y3 rocket plunged to Earth over the Indian Ocean on Saturday

The 23-tonne core stage of China’s Long March 5B-Y3 rocket plunged to Earth over the Indian Ocean on Saturday

‘Not especially,’ McDowell said, when asked whether there was an increased risk, ‘because most countries are being better about disposing of the larger debris safely.’

He added: ‘The Long March 5B is the most worrying one because it is so large. But there is a (lower) risk from the debris from all countries.’

McDowell believes that instead of being an increasing risk, it is instead one ‘we are becoming more aware of’. 

‘All space agencies have taken measures to reduce the amount of falling space debris but the current norms are still not strict enough, as the Australian incident shows,’ he added.

McDowell has kept a list of the biggest uncontrolled reentries, dating back to the Sputnik rocket in 1958. 

China’s Long March 5B is the latest to be added to that list.

It blasted off from Hainan Island at 2:22pm local time on July 24, before delivering a new module to China’s Tiangong space station.

It then began an uncontrolled descent toward Earth’s atmosphere, leading to China being accused for a third time of not properly handling space debris from its rocket stage.

Yet another out-of-control Chinese rocket sparked concern — a year after one of Beijing's spacecrafts showered debris over the Indian Ocean

Yet another out-of-control Chinese rocket sparked concern — a year after one of Beijing’s spacecrafts showered debris over the Indian Ocean 

HOW MANY ITEMS ARE THERE IN ORBIT? 

  • Rocket launches since 1957:  6,200
  • Number of satellites in orbit: 13,100 
  • Number still in space: 8,410 
  • Number still functioning: 5,800
  • Number of debris objects: 31,500
  • Break-ups, explosions etc: 630 
  • Mass of objects in orbit: 9,900 tonnes 
  • Prediction of the amount of debris in orbit using statistical models 
  • Over 10cm: 36,500 
  • 1cm to 10cm: 1,000,000 
  • 1mm to 1cm: 130 million 

Source: European Space Agency 

SpaceX is yet to acknowledge the Australian debris as its own, but experts say its re-entry path matches that of the Crew-1 Trunk, which is the unpressurised bottom part of the capsule.

Launched in 2020, SpaceX Crew-1 was the first operational crewed flight of a Crew Dragon spacecraft.

Last month, scientists at the University of British Columbia in Vancouver analysed the risk to human life of objects plummeting to the ground after re-entering the Earth’s atmosphere.

Under current practices, the researchers found that, if a typical rocket re-entry spreads debris across a 10 square metre (108 sq ft) area, then there is roughly a 1 in 10 chance that one or more casualties will occur over the next 10 years.

They also said there was a higher risk to those living in the global south, with errant parts three times more likely to land at the latitudes of Jakarta, Dhaka and Lagos than those of New York, Beijing or Moscow. 

However, despite 80 per cent of the world’s people living in what is known as a ‘risk zone’, just 0.1 per cent of it is considered populated.

‘Everything else is ocean, forest or agricultural land,’ said Dr Shane Walsh, a research fellow at the International Centre for Radio Astronomy Research. 

‘It’s extremely unlikely to cause damage or loss of life.’

The problem with China’s rockets is rooted in the risky design of the country’s launch process.

Usually, discarded rocket stages re-enter the atmosphere soon after liftoff, normally over water, and don’t go into orbit.

However, the Long March 5B rocket does.

There have been calls by NASA for the Chinese space agency to design rockets to disintegrate into smaller pieces upon re-entry, as is the international norm. 

But China has previously rejected accusations of irresponsibility, with the Chinese Foreign Ministry saying the likelihood of damage to anything or anyone on the ground is ‘extremely low’.

US Space Command confirmed that the debris re-entered the atmosphere at approximately 12.45pm ET on Saturday, referring all questions about the precise location of re-entry and debris dispersal to the Chinese government.

NASA said Beijing had not shared the ‘specific trajectory information’ needed to calculate where possible debris might fall.

It had been feared that the debris could land in Mexico, but it ultimately landed in the ocean, without causing any injuries or damage.

‘All spacefaring nations should follow established best practices and do their part to share this type of information in advance to allow reliable predictions of potential debris impact risk,’ NASA Administrator Bill Nelson said. 

‘Doing so is critical to the responsible use of space and to ensure the safety of people here on Earth.’

A recent study claimed there was a higher risk to those living in the global south, with errant parts three times more likely to land at the latitudes of Jakarta, Dhaka and Lagos than those of New York, Beijing or Moscow. Some major and high-risk cities are labelled: 1, Moscow; 2, Washington, DC; 3, Beijing; 4, Dhaka; 5, Mexico City; 6, Lagos; 7, Bogotá; 8, Jakarta

A recent study claimed there was a higher risk to those living in the global south, with errant parts three times more likely to land at the latitudes of Jakarta, Dhaka and Lagos than those of New York, Beijing or Moscow. Some major and high-risk cities are labelled: 1, Moscow; 2, Washington, DC; 3, Beijing; 4, Dhaka; 5, Mexico City; 6, Lagos; 7, Bogotá; 8, Jakarta

This pie chart shows the proportion of the global casualty expectation contributed by each state

This pie chart shows the proportion of the global casualty expectation contributed by each state

WHAT IS TIANGONG? 

China’s space station is called ‘Tiangong‘, meaning ‘Heavenly Palace’.

Tiangong is comprised of several different modules that are launching one by one.

In April 2021, the core module, called ‘Tianhe‘, was launched. The first crew arrived at Tianhe two months later. 

In July 2022, Wentian, a smaller module where research experiments will take place, attached to Tianhe. 

In October 2022, a second research lab module, Mengtian, will also attach to Tianhe. When it does, the Tiangong space station will be complete. 

Another two spacecraft that can dock at the station – Shenzhou and Tianzhou – respectively transport crew and cargo, and aren’t considered part of the station itself. 

China also plans to launch Xuntian, a space telescope that would co-orbit with the space station, in 2024.

Last May, one of the country’s Long March rockets broke up on re-entry above the Indian Ocean, north of the Maldives, leading to concerns that it could smash into a populated area on land.

It ultimately fell into the ocean, but Nelson still issued a strongly-worded statement which said: ‘Spacefaring nations must minimise the risks to people and property on Earth of re-entries of space objects and maximise transparency regarding those operations.’

In 2020, pieces from the first Long March 5B fell on Ivory Coast, damaging several buildings but not causing any injuries. 

Although rocket launches vary, boosters and other sizeable parts from rockets fall back to Earth or are abandoned in orbit. 

In most cases, the abandoned rocket parts re-enter the atmosphere in an uncontrolled fashion and debris may land anywhere along the flight path.

An estimated 13,100 satellites have been launched into orbit since 1957, according to the European Space Agency, with 8,410 remaining in space and 5,800 still functioning.

The total mass of all objects in orbit is said to equate to around 9,900 tonnes, while statistical models suggests there are 130 million pieces of debris from 1mm to 1cm in size.

In June, the UK government announced plans for an ‘RAC for space’ as part of its vision to tackle millions of shards of debris clogging up near-Earth orbit

It also wants to improve the sustainability of future space missions, with Science Minister George Freeman issuing a stern warning to the likes of Russia and China that ‘the days of putting up whatever they want have got to be over’.

He said a ‘Wild West’ space race without effective regulation would only serve to increase the growing threat of debris in orbit, including hundreds of old satellites.

Farmer Mick Miners (pictured) discovered the huge piece of space junk from SpaceX stuck in his property in the Snowy Mountains, south of Jindabyne

Farmer Mick Miners (pictured) discovered the huge piece of space junk from SpaceX stuck in his property in the Snowy Mountains, south of Jindabyne 

Australian National University space expert Brad Tucker confirmed it was part of Elon Musk's SpaceX Crew-1 (pictured)

Australian National University space expert Brad Tucker confirmed it was part of Elon Musk’s SpaceX Crew-1 (pictured)  

Mr Freeman also told MailOnline that he expected Elon Musk to fall in line with Britain’s push for space sustainability, adding that the need for action was not something the US billionaire could ignore.

Critics of Musk say his Starlink constellation is hogging space, with both China and the European Space Agency taking aim at his satellite-internet system, but the Tesla founder has rubbished these fears.

The UK government’s raft of new measures includes regulating commercial satellite launches, rewarding companies that minimise their footprint on the Earth’s orbit, and dishing out an additional £5 million for technologies to clean up space junk.

WHAT IS SPACE JUNK? MORE THAN 170 MILLION PIECES OF DEAD SATELLITES, SPENT ROCKETS AND FLAKES OF PAINT POSE ‘THREAT’ TO SPACE INDUSTRY

There are an estimated 170 million pieces of so-called ‘space junk’ – left behind after missions that can be as big as spent rocket stages or as small as paint flakes – in orbit alongside some US$700 billion (£555bn) of space infrastructure.

But only 27,000 are tracked, and with the fragments able to travel at speeds above 16,777 mph (27,000kmh), even tiny pieces could seriously damage or destroy satellites.

However, traditional gripping methods don’t work in space, as suction cups do not function in a vacuum and temperatures are too cold for substances like tape and glue.

Grippers based around magnets are useless because most of the debris in orbit around Earth is not magnetic.

Around 500,000 pieces of human-made debris (artist’s impression) currently orbit our planet, made up of disused satellites, bits of spacecraft and spent rockets

Most proposed solutions, including debris harpoons, either require or cause forceful interaction with the debris, which could push those objects in unintended, unpredictable directions.

Scientists point to two events that have badly worsened the problem of space junk.

The first was in February 2009, when an Iridium telecoms satellite and Kosmos-2251, a Russian military satellite, accidentally collided.

The second was in January 2007, when China tested an anti-satellite weapon on an old Fengyun weather satellite.

Experts also pointed to two sites that have become worryingly cluttered.

One is low Earth orbit which is used by satnav satellites, the ISS, China’s manned missions and the Hubble telescope, among others.

The other is in geostationary orbit, and is used by communications, weather and surveillance satellites that must maintain a fixed position relative to Earth.