The Times Australia
The Times World News

.

Space is getting crowded with satellites and space junk. How do we avoid collisions?

  • Written by Sara Webb, Postdoctoral Research Fellow, Centre for Astrophysics and Supercomputing, Swinburne University of Technology
Space is getting crowded with satellites and space junk. How do we avoid collisions?

Reports this week suggest a near-collision[1] between an Australian satellite and a suspected Chinese military satellite.

Meanwhile, earlier this month, the US government issued the first ever space junk fine. The Federal Communications Commission handed a US$150,000 penalty[2] to the DISH Network, a publicly traded company providing satellite TV services.

It came as a surprise to many in the space industry, as the fine didn’t relate to any recent debris – it was issued for a communications satellite that has been in space for more than 21 years. It was EchoStar-7[3], which failed to meet the orbit requirements outlined in a previously agreed debris mitigation plan.

The EchoStar-7 fine might be a US first, but it probably won’t be the last. We are entering an unprecedented era of space use and can expect the number of active satellites in space[4] to increase by 700% by the end of the decade.

As our local space gets more crowded, keeping an eye on tens of thousands of satellites and bits of space junk will only become more important. So researchers have a new field for this: space domain awareness.

Three types of orbit, plus junk

Humans have been launching satellites into space since 1957 and in the past 66 years have become rather good at it. There are currently more than 8,700 active satellites[5] in various orbits around Earth.

Satellites tend to be in three main orbits, and understanding these is key to understanding the complex nature of space debris.

An image of Earth with circles around it to indicate the distance of standard satellite orbits
Types of orbits around Earth classified by altitude (not to scale). Pexels/The Conversation, CC BY-SA[6]

The most common orbit for satellites is low Earth orbit[7], with at least 5,900 active satellites[8]. Objects in low Earth orbit tend to reside up to 1,000km above Earth’s surface and are constantly on the move. The International Space Station is an example of a low Earth orbit object, travelling around Earth 16 times every day.

Higher up is the medium Earth orbit[9], where satellites sit between 10,000 and 20,000km above Earth. It’s not a particularly busy place, but is home to some of the most important satellites ever launched – they provide us with the global positioning system[10] or GPS.

Finally, we have very high altitude satellites in geosynchronous orbit[11]. In this orbit, satellites are upwards of 35,000km above Earth, in orbits that match the rate of Earth’s rotation. One special type of this orbit is a geostationary Earth orbit. It lies on the same plane as Earth’s equator, making the satellites appear stationary from the ground.

Visualisation of The European Space Agency’s Space Debris Office statistics on space debris orbiting Earth (as of January 8 2021).

As you can tell, Earth’s surrounds are buzzing with satellite activity. It only gets more chaotic when we factor in space junk[12], defined as disused artificial debris in orbit around Earth.

Space junk can range from entire satellites that are no longer in use or working, down to millimetre-wide bits of spacecraft and launch vehicles left in orbit. Latest estimates[13] suggest there are more than 130 million pieces of space debris, with only 35,000 of those large enough (greater than 10cm) to be routinely tracked from the ground.

Read more: Space junk in Earth orbit and on the Moon will increase with future missions − but nobody's in charge of cleaning it up[14]

How do we track them all?

This is where space domain awareness comes in. It is the field of detecting, tracking and monitoring objects in Earth’s orbit, including active satellites and space debris.

We do much of this with ground-based tracking, either through radar or optical systems like telescopes. While radar can easily track objects in low Earth orbit, higher up we need optical sensors. Objects in medium Earth orbit and geostationary orbit can be tracked using sunlight reflected towards Earth.

For reliable and continuous space domain awareness, we need multiple sensors contributing to this around the globe.

Below you can see what high-altitude satellites can look like to telescopes on Earth, appearing to stay still as the stars move by.

Tracking two Optus satellites 16km apart, using EOS’ 0.7m deep space telescope at Learmonth, Western Australia. Source: EOS - Electro Optic Systems.

Australia’s role in space awareness

Thanks to our position on Earth, Australia has a unique opportunity to contribute to space domain awareness. The US already houses several facilities on the west coast of Australia as part of the Space Surveillance Network[15]. That’s because on the west coast, telescopes can work in dark night skies with minimal light pollution from large cities.

Furthermore, we are currently working on a space domain awareness technology demonstrator[16] (a proof of concept), funded by SmartSat CRC[17]. This is a government-funded consortium of universities and other research organisations, along with industry partners such as the IT firm CGI.

We are combining our expertise in observational astrophysics, advanced data visualisation, artificial intelligence and space weather. Our goal is to have technology that understands what is happening in space minute-by-minute. Then, we can line up follow-up observations and monitor the objects in orbit. Our team is currently working on geosynchronous orbit objects, which includes active and inactive satellites.

EchoStar-7 was just one example of the fate of a retired spacecraft – the FCC is sending a strong warning to all other companies to ensure their debris mitigation plans are met.

Inactive objects in orbit could pose a collision risk to each other, leading to a rapid increase in space debris. If we want to use Earth’s space domain for as long as possible, we need to keep it safe for all.

Read more: Harpoons, robots and lasers: how to capture defunct satellites and other space junk and bring it back to Earth[18]

Acknowledgment: The authors would like to thank Sholto Forbes-Spyratos, military space lead at CGI Space, Defence and Intelligence Australia, for his contribution to this article.

References

  1. ^ a near-collision (theconversation.com)
  2. ^ handed a US$150,000 penalty (www.fcc.gov)
  3. ^ EchoStar-7 (nssdc.gsfc.nasa.gov)
  4. ^ satellites in space (time.com)
  5. ^ more than 8,700 active satellites (orbit.ing-now.com)
  6. ^ CC BY-SA (creativecommons.org)
  7. ^ low Earth orbit (www.esa.int)
  8. ^ 5,900 active satellites (www.ucsusa.org)
  9. ^ medium Earth orbit (www.esa.int)
  10. ^ global positioning system (www.gps.gov)
  11. ^ geosynchronous orbit (www.esa.int)
  12. ^ space junk (www.nhm.ac.uk)
  13. ^ Latest estimates (www.esa.int)
  14. ^ Space junk in Earth orbit and on the Moon will increase with future missions − but nobody's in charge of cleaning it up (theconversation.com)
  15. ^ Space Surveillance Network (nsarchive.gwu.edu)
  16. ^ space domain awareness technology demonstrator (www.cgi.com)
  17. ^ SmartSat CRC (smartsatcrc.com)
  18. ^ Harpoons, robots and lasers: how to capture defunct satellites and other space junk and bring it back to Earth (theconversation.com)

Read more https://theconversation.com/space-is-getting-crowded-with-satellites-and-space-junk-how-do-we-avoid-collisions-215545

Times Magazine

Building a Strong Online Presence with Katoomba Web Design

Katoomba web design is more than just creating a website that looks good—it’s about building an online presence that reflects your brand, engages your audience, and drives results. For local businesses in the Blue Mountains, a well-designed website a...

September Sunset Polo

International Polo Tour To Bridge Historic Sport, Life-Changing Philanthropy, and Breath-Taking Beauty On Saturday, September 6th, history will be made as the International Polo Tour (IPT), a sports leader headquartered here in South Florida...

5 Ways Microsoft Fabric Simplifies Your Data Analytics Workflow

In today's data-driven world, businesses are constantly seeking ways to streamline their data analytics processes. The sheer volume and complexity of data can be overwhelming, often leading to bottlenecks and inefficiencies. Enter the innovative da...

7 Questions to Ask Before You Sign IT Support Companies in Sydney

Choosing an IT partner can feel like buying an insurance policy you hope you never need. The right choice keeps your team productive, your data safe, and your budget predictable. The wrong choice shows up as slow tickets, surprise bills, and risky sh...

Choosing the Right Legal Aid Lawyer in Sutherland Shire: Key Considerations

Legal aid services play an essential role in ensuring access to justice for all. For people in the Sutherland Shire who may not have the financial means to pay for private legal assistance, legal aid ensures that everyone has access to representa...

Watercolor vs. Oil vs. Digital: Which Medium Fits Your Pet's Personality?

When it comes to immortalizing your pet’s unique personality in art, choosing the right medium is essential. Each artistic medium, whether watercolor, oil, or digital, has distinct qualities that can bring out the spirit of your furry friend in dif...

The Times Features

How much money do you need to be happy? Here’s what the research says

Over the next decade, Elon Musk could become the world’s first trillionaire[1]. The Tesla board recently proposed a US$1 trillion (A$1.5 trillion) compensation plan, if Musk ca...

NSW has a new fashion sector strategy – but a sustainable industry needs a federally legislated response

The New South Wales government recently announced the launch of the NSW Fashion Sector Strategy, 2025–28[1]. The strategy, developed in partnership with the Australian Fashion ...

From Garden to Gift: Why Roses Make the Perfect Present

Think back to the last time you gave or received flowers. Chances are, roses were part of the bunch, or maybe they were the whole bunch.   Roses tend to leave an impression. Even ...

Do I have insomnia? 5 reasons why you might not

Even a single night of sleep trouble can feel distressing and lonely. You toss and turn, stare at the ceiling, and wonder how you’ll cope tomorrow. No wonder many people star...

Wedding Photography Trends You Need to Know (Before You Regret Your Album)

Your wedding album should be a timeless keepsake, not something you cringe at years later. Trends may come and go, but choosing the right wedding photography approach ensures your ...

Can you say no to your doctor using an AI scribe?

Doctors’ offices were once private. But increasingly, artificial intelligence (AI) scribes (also known as digital scribes) are listening in. These tools can record and trans...