Viw Magazine

  • Written by Gregory Cohen, Associate Professor, Western Sydney University
The now defunct Infrared Astronomical Telescope was one of the satellites involved in the near-collision. NASA/JPL

It appears we have missed another close call between two satellites – but how close did we really come to a catastrophic event in space?

It all began with a series of tweets from LeoLabs, a company that uses radar to track satellites and debris in space. It predicted that two obsolete satellites orbiting Earth had a 1 in 100 chance of an almost direct head-on collision at 9:39am AEST on 30 January, with potentially devastating consequences.

LeoLabs estimated that the satellites could pass within 15-30m of one another. Neither satellite could be controlled or moved. All we could do was watch whatever unfolded above us.

Collisions in space can be disastrous and can send high-speed debris in all directions. This endangers other satellites, future launches, and especially crewed space missions.

As a point of reference, NASA often moves the International Space Station when the risk of collision is just 1 in 100,000. Last year the European Space Agency moved one of its satellites when the likelihood of collision with a SpaceX satellite was estimated at 1 in 50,000. However, this increased to 1 in 1,000 when the US Air Force, which maintains perhaps the most comprehensive catalogue of satellites, provided more detailed information.

Read more: You, me and debris: Australia should help clear 'space junk'

Following LeoLabs’ warning, other organisations such as the Aerospace Corporation began to provide similarly worrying predictions. In contrast, calculations based on publicly available data were far more optimistic. Neither the US Air Force nor NASA issued any warning.

This was notable, as the United States had a role in the launch of both satellites involved in the near-miss. The first is the Infrared Astronomical Satellite (IRAS), a large space telescope weighing around a tonne and launched in 1983. It successfully completed its mission later that year and has floated dormant ever since.

The second satellite has a slightly more intriguing story. Known as GGSE-4, it is a formerly secret government satellite launched in 1967. It was part of a much larger project to capture radar emissions from the Soviet Union. This particular satellite also contained an experiment to explore ways to stabilise satellites using gravity.

Weighing in at 83kg, it is much smaller than IRAS, but it has a very unusual and unfortunate shape. It has an 18m protruding arm with a weight on the end, thus making it a much larger target.

Almost 24 hours later, LeoLabs tweeted again. It downgraded the chance of a collision to 1 in 1,000, and revised the predicted passing distance between the satellites to 13-87m. Although still closer than usual, this was a decidedly smaller risk. But less than 15 hours after that, the company tweeted yet again, raising the probability of collision back to 1 in 100, and then to a very alarming 1 in 20 after learning about the shape of GGSE-4.

The good news is that the two satellites appear to have missed one another. Although there were a handful of eyewitness accounts of the IRAS satellite appearing to pass unharmed through the predicted point of impact, it can still take a few hours for scientists to confirm that a collision did not take place. LeoLabs has since confirmed it has not detected any new space debris.

But why did the predictions change so dramatically and so often? What happened?

Tricky situation

The real problem is that we don’t really know precisely where these satellites are. That requires us to be extremely conservative, especially given the cost and importance of most active satellites, and the dramatic consequences of high-speed collisions.

The tracking of objects in space is often called Space Situational Awareness, and it is a very difficult task. One of the best methods is radar, which is expensive to build and operate. Visual observation with telescopes is much cheaper but comes with other complications, such as weather and lots of moving parts that can break down.

Another difficulty is that our models for predicting satellites’ orbits don’t work well in lower orbits, where drag from Earth’s atmosphere can become a factor.

There is yet another problem. Whereas it is in the best interest of commercial satellites for everyone to know exactly where they are, this is not the case for military and spy satellites. Defence organisations do not share the full list of objects they are tracking.

This potential collision involved an ancient spy satellite from 1967. It is at least one that we can see. Given the difficulty of just tracking the satellites that we know about, how will we avoid satellites that are trying their hardest not to be seen?

Read more: Trash or treasure? A lot of space debris is junk, but some is precious heritage

In fact, much research has gone into building stealth satellites that are invisible from Earth. Even commercial industry is considering making satellites that are harder to see, partly in response to astronomers’ own concerns about objects blotting out their view of the heavens. SpaceX is considering building “dark satellites” the reflect less light into telescopes on Earth, which will only make them harder to track.

What should we do?

The solution starts with developing better ways to track satellites and space debris. Removing the junk is an important next step, but we can only do that if we know exactly where it is.

Western Sydney University is developing biology-inspired cameras that can see satellites during the day, allowing them to work when other telescopes cannot. These sensors can also see satellites when they move in front of bright objects like the Moon.

There is also no clear international space law or policy, but a strong need for one. Unfortunately, such laws will be impossible to enforce if we cannot do a better job of figuring out what is happening in orbit around our planet.

Gregory Cohen receives funding for space applications of neuormorphic imaging from the Royal Australian Air Force (RAAF), the United States Air Force Office of Scientific Research (AFOSR), and the Defense Innovation Hub (DIH).

Authors: Gregory Cohen, Associate Professor, Western Sydney University

Read more

How to Tell If a Power Surge Has Occurred

Power surges are notorious for causing damage to electronic devices. It can be inconvenient to lose valuable data on your computer or re... - avatar

How to keep your family safe with a smoke detector

An out-of-control fire in your home is not a usual event, however, the risk of fire is around every single day. There are plenty of ways... - avatar

What is an IoT?

The Internet of Things (IoT) refers to our increasingly networked physical world, where everyday objects and devices are connected t...

Viw Magazine - avatar Viw Magazine

How to Become a Marine Mechanic – Tips You'll Need to Know

Marine mechanics are the most important people in a ship's crew. They are responsible for maintaining and repairing the ship's engines, ...

Viw Magazine - avatar Viw Magazine

What Are Modern Rugs And Their Types?

What Are Modern Rugs? As the term suggests, these contemporary rugs will usually feature bold colours and free-form styling elements. T... - avatar

Popular ways to make money on online platforms in Australia

Making money online in most countries is not too big of a difference, the minimum condition we need is the development of the online bus... - avatar

Just make it simple: why you should definitely enlist a tax agent

We totally get it: tax time is everyone’s least favourite time of the year. If it’s not the moment when you realise your financial f... - avatar

Benefits of Cognitive Behaviour Therapy

Do you want the good news, or the bad news first? That was a trick question, there is no such thing as good or bad, everything that happen... - avatar

Pre-Purchase And Pest Inspection: Everything To Know About

Buying a dream house involves a larger financial investment. Finding a magnificent property takes a lot of money and time, and the last ... - avatar

How to Keep Your Home Safe: An Overview of Safety Switches

Homeowners are responsible for electrical and appliance safety in the home. This includes understanding the security measures necessary ... - avatar

Go Long: Hair Extensions 101

Hair pieces and wigs have been around since C.2700 BCE, when Egyptians used a combination of sheep’s wool and human hair to create the...

Viw Magazine - avatar Viw Magazine

Common Toilet Repairs and How to Fix Them

There are some toilet repairs that require you to call Ryan Old Plumbing Services in Brisbane, but there are quite a few that you can ha... - avatar

Best Christmas Decorating Tips For Small Spaces

Christmas is one of the most exciting times of the year because everyone gets the opportunity to creatively express their festivity throug...

Viw Magazine - avatar Viw Magazine

How to organise your bedroom for better sleep

Could your bedroom be the culprit for your lack of sleep?   There are a myriad of factors contributing to insomnia or sleeplessness, ... - avatar

9 Awesome Reasons to Live in Nowra

Nowra is a vibrant town, popular as Shoalhaven city’s commercial hub. It lies along the glorious banks of the Shoalhaven River, stretchi... - avatar

Signs and Indicators That You Need Duct Cleaning Services in Your Home or Office

If you live in an older home with forced-air air heating and cooling, you’ll likely need to have your ducts cleaned eventually. Howeve... - avatar

7 Reasons to Install Fly Screens At Home

Fly screens are designed to keep insects from your space, but they also have other benefits. They keep bugs, debris, and pests out while... - avatar

How MBA Helps in Business? 8 Reasons Why Business Owners Should Get An MBA

Business owners have a lot of responsibilities. They have to take care of the day-to-day operations of their business, as well as the lo... - avatar

Know More on Double Sink Bathroom Vanities, Styles, Installation & Tips

Double sink bathroom vanities are popular because they provide a lot of storage and counter space. They are also great for couples becau...

Viw Magazine - avatar Viw Magazine

Hosted VoIP Business Phone Systems - Pros and Cons

A hosted VoIP business phone system Australia is a cloud-based phone system that delivers calls over the internet rather than through a trad... - avatar

Writers Wanted

Content & Technology Connecting Global Audiences

More Information - Less Opinion