Menu Close
Unless something is done about space junk, it might become too unsafe to have satellites in Low-Earth Orbit. ESA

You, me and debris: Australia should help clear ‘space junk’

At some point in the next few months, Australia will get its first ever national space policy.

The release of the report, following consultation by experts in the space industry, will be a defining moment in Australia’s contribution to space-related endeavours.

Importantly, it will signal to observers, both domestically and internationally, that Australia, in future, will likely play a greater role in tackling the space-related challenges facing the international community.

Space junk

One of the most immediate challenges is that of so-called “space junk”, especially in Low-Earth Orbits (LEO) between 300 and 1,000km above the earth.

Most of these pieces of space junk are of human origin, such as decommissioned satellites and the debris that results from collisions between these satellites. It is estimated there are as many as 20,000 pieces of “trackable” space junk in orbit with possibly millions of smaller objects also in LEO.

So, why is this a problem?

As you read this, hundreds of working satellites are circling the earth in LEO. Most Earth-observation satellites operate in LEO, as does the International Space Station (ISS) and other orbital missions with humans on board.

With satellites in LEO typically travelling at roughly 17,000km/h, any collision with space junk is likely to be catastrophic. Additionally, such a collision will almost certainly create further space junk.

The chain reaction effect of collisions, unless reversed, may see LEO space simply denied to satellite operators because the collision risks are too high.

Australia’s reliance

Although Australia confines its participation in human space missions to the hosting of mission-support ground stations, the nation is heavily dependent on data from Earth-observation satellites to support numerous national security, civil, research and commercial applications which provide vital information for policy development and decision-making.

Australia has a vested interest in ensuring space remains a domain to which all nations can enjoy assured and secure access long into the future.

To realise this ambition, there is an emerging international consensus, reflected in current space Code of Conduct discussions, that space junk doesn’t only need to be tracked with great accuracy, but that some larger pieces may need to be brought back to Earth or at least brought into the earth’s atmosphere where they will burn up.

The difficulty is that a space garbage truck to one nation may be characterised as a space weapon by another. Such is the dual-use nature of all aspects of space operations that the global community, especially the spacefaring nations, will need to move with great care and caution as they nudge towards agreements to clean up space.

Space monitoring

Australia is becoming increasingly involved in the future of space regulation at the heart of which is the question of space debris monitoring and mitigation.

In January 2012, the government announced support for a European Union initiative to develop a Code of Conduct to regulate the activities of spacefaring nations in the future.

The key driver is that space, especially in LEO, is becoming increasingly congested. The vastness of the space domain is no longer a guarantee that collisions will not occur.

The situation is not dissimilar to that on the roads at the end of the 19th century. When cars were first invented there were so few of them that regulations were not needed. As cars became more common, rules were developed – keep left, or right as the case may be – greater attention was paid to safety standards and, more recently, to rules about the disposal of old vehicles.

Eyes on the sky

Space Situational Awareness (SSA) is the phrase used to describe our understanding of where objects are in space, in absolute and relative terms.

The US has the most comprehensive and reliable system for tracking space objects, called the Space Surveillance Network (SSN). Presently, the SSN monitors in the order of 25,000 separate space objects, mostly “space junk” in LEO.

And while the US’s SSN is the most comprehensive space-junk monitoring program in the world, it has no ground-based sensors in the southern hemisphere. The same is true of other space surveillance networks, including those of China and Russia.

Radar relocation

Australia is seeking to redress this situation through a recently announced Defence project, known as Joint Project 3029, which aims to relocate a ground-based space surveillance radar from the US to Australia, possibly to North West Cape. Data from this radar is proposed to feed into the US SSN.

The 2012 edition of the Defence Capability Plan describes the radar relocation project as a vital capability. It also points to the importance of having a sensor based in the southern hemisphere.

Most importantly, the plan states Australia, through investment in this project, is seeking to both gain understanding of the space environment and also to contribute to its better characterisation.

Space environmental management

A separate initiative is being led by a Canberra-based company, Electro-Optic Systems (EOS). This company is leading an application to form, in collaboration with ANU and RMIT, a Cooperative Research Centre (CRC) in Space Environmental Management.

NASA has expressed interest in joining the consortium, should the application proceed. The CRC, which has a strong technology focus has four main objectives:

  1. to develop more accurate ways of calculating and predicting the future orbits of space debris so satellite operators have plenty of time to move satellites to avoid collisions

  2. to develop and test techniques to use ground-based lasers (the pressure of photons) to nudge objects in orbit in order to avoid collisions

  3. to develop advanced optics, which also have direct application in next-generation telescopes, to support the laser technologies

  4. to develop and test techniques to use ground-based lasers to oblate (roughen the surface) of selected items of space debris in order to increase the amount of drag they experience thus bringing them back to Earth more quickly.

A seat at the table

Hand-in-glove with technology development, there must be an international discussion involving spacefaring nations – including the US, Russia, China, India and Japan – and space-dependent nations, including Australia.

This discussion must give nations confidence that space debris mitigation and not space weaponisation is the fundamental purpose of the technologies being developed and, hopefully, applied.

Australia is well-placed geographically and politically to not only lead these discussions and research but also to apply the results operationally.

The forthcoming national space policy, together with the diplomatic and technological initiatives described above may yet lead to a golden age for Australian space endeavours. Not least in debris management and mitigation, to the benefit of many nations and the global economy more generally.

This is the final of three articles by Brett Biddington about the past, present and future of Australia’s efforts in space:

Want to write?

Write an article and join a growing community of more than 174,800 academics and researchers from 4,812 institutions.

Register now