"Space…The final frontier.” When we first heard these words spoken by the ‘Star Trek’ actor William Shatner as Captain James Tiberius Kirk of USS Enterprise on television in 1966, space was indeed thought of as humankind’s final frontier. Several years before, the USSR had taken humanity’s radio technology into this frontier with Sputnik-1. In 1965, the first commercial communications satellite had been launched, and a few years later American scientists, technicians, and astronauts pushed humanity’s frontier by landing on the surface of the Moon.
Final Frontiers!
Nowadays, thanks to incredible satellite technologies, and orbiting and deep space instrument-based findings and observations supporting equally incredible theoretical advances, we know more about the outer space that is very far away from us than we do about the inner space of Earth’s deep oceans. It is the deep oceans that are today’s real “final frontier”. Interestingly, and central to the thoughts presented here, space and the oceans, as frontiers, unfortunately have something in common… Human activity is compromising them both, in different ways, of course, but potentially with parallel, or equivalent, catastrophic results.
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| From 17-18 May for The Satexpo Sumit at CABSAT in Dubai will be tacking the issues discussed in this article in pnaels sucha s ‘Stakes and Solutions in Responsibly Managing Space’ and for ‘Disruptive Evolution in the Satellite Ground Segment’ and ‘Driving a New Space Innovation Paradigm with Artificial Intelligence and Machine Learning’. |
As the oceans of the CO2-emission and methane-emission saturated anthropocene epoch get warmer, become increasingly acidified, and are filled with plastic waste, we observe just one facet of the human-vectored threat to Earth’s interconnected ecosystems. Of course it is by using space, at least that part of it that lies within the low earth orbit (LEO) range of the planet’s overall useful orbital assets – between the Karmen line (altitude approx 100km) and the geostationary arc (altitude approx 36,000km) – that we are able to most effectively measure the magnitude of these threats with remote sensing satellites. It would be extremely damaging to the potential of our efforts to monitor the various inputs and outputs of Earth’s shifting climate trends if we lost the ability to do so from orbit; and yet our anthropocene activities are extending and impacting beyond the limits of Earth’s immediate ecosphere. There is a deep synergy between ensuring humanity’s continuing climate security on the surface of the planet, and ensuring that Earth’s LEO is kept safe and secure – is kept for ongoing sustainable use.
Our Orbital Space
Of course, it is not only LEO – whether used for the remote sensing noted above, or used increasingly for broadband communications – that is vitally important to us here on Earth. GEO has long been, and remains, vital too. The potential of geostationary orbit was, of course, first identified as important by a man who (as I have previously written) is synonymous with humankind’s exploration of the extreme frontiers of space, albeit usually within the realms of science fiction. Arthur C. Clarke’s ‘Wireless World’ article prompted the following decades-long journey of using the geostationary arc above the Earth’s equator to locate communications satellites which throughout these decades have become increasingly powerful and capable. GEOs are a technological resource without which the planet’s communications networks would simply not function. As the satellite population of the geostationary arc has grown, there have been problems to be resolved… but development of solutions has followed.
For example, there is a legal obligation on bodies like the US Federal Communications Commission at the national level, and the International Telecommunication Union internationally, to ensure that the activities of satellite operators do not interfere with each other. In another example, good practice in the installation of satellite ground terminals to avoid adjacent satellite interference (ASI) has been encouraged and facilitated through accessible (i.e., online) training such as that developed by GVF Training which has successfully reached over 20,000 students worldwide. In yet another example, GEO satellites at end-of-life after 15, or perhaps, 17 years, must have a sufficient remaining station-keeping fuel supply to be maneuvered to a graveyard orbit. The GEO orbital arc is very busy with just two degree spacing between slots, but good husbandry of this orbit ensures that navigation to a graveyard slot means it will take many many thousands of years for the planet’s gravitational attraction to decay their orbit to a plasma-engulfed end in the atmosphere.
Most recently, we have gone further to enhance the good management of GEO space. The Mission Extension Vehicle (MEV-1) successfully performed an automated rendezvous with a non-transmitting satellite which required an in-orbit service check and re-fueling in February 2020. Later, MEV-2 successfully docked with and refueled a still fully functional satellite but which was running low on propellant.
How Many is a Crowd?
Our usable orbital space is getting more and more crowded: [a] In the commercial sphere (i.e., in satellite communications and Earth observation); [b] In the government sphere (e.g., in activity by increasing numbers of national space agencies); [c] In the military sphere (e.g., including the increased potential for various types of anti-satellite – A-sat – technology); [d] In the research and technology sphere (e.g., in satellite future technology demonstrator projects, orbit-based industrial product development and manufacturing in pharmaceuticals and other sectors); [e] In the space resources management sphere (e.g., orbital debris removal and other debris mitigations, mission extension missions and automated satellite repair, orbital tow trucking); and not forgetting, [f] In the entertainment sphere (e.g., multi-million-dollar-ticket sub-orbital joyrides and space hotels).
With [a] satellite communications in all orbital planes will continue to get busier and more competitive as even more powerful examples of high-throughput GEOs are launched, as a new generation of MEOs are orbited, as existing LEO constellations grow, and the building of more LEO constellations begins; in Earth observation, particularly with satellites scaled as multi-unit cubesats. With [b] more and more countries, including some in the low GDP range, have founded a national space agency as both a mechanism to promote bilateral or multilateral cooperation with other countries’ agencies and to promote national space-related capabilities in aspects of satcoms (e.g., Internet of Things – IoT) and Earth observation/remote sensing (e.g., deforestation monitoring, agricultural monitoring, climate change monitoring, ocean monitoring). With [c] A-sat technology can include missile systems, kinetic anti-satellite weapons, etc. With [d] space and satellite technology development which may be the means to other ends, such as S.T.E.M. development. With [e] the consequences of increased volumes of orbital activity and numbers of spacecraft requiring servicing, as per [a], means that further satellite-based technology will be needed to manage an increasingly populated orbital environment.
Good Practice in Our Orbital Space Management
The international policy discussion and regulatory environment is likely to become more “heated” during the next years as nations, international agencies and organizations, and commercial entities become further embroiled in dialogue about not only long-standing issues concerning spectrum access rights and radio frequency interference issues, but also regulation on orbital debris and mitigating the potential of the “Kessler Syndrome”, as well as attempts to prevent A-sat activity.
An orbiting population of 100,000 or more satellites is likely by the end of this decade, and already an estimated 170 million man-made objects are in space. These objects comprise active satellites, derelict satellites, launcher stages, and ‘debris’ resulting from fragmentations, explosions and collisions which, when more than 10cm in size, can be tracked (there are over 22,000 objects in ‘The General Catalog of Artificial Space Objects’), with anything smaller being untrackable.
This density of “junk”, however it arises, and even when objects are quite small (but traveling at high velocity), threatens humanity’s essential access to useful space, potentially rendering impractical many space activities and the use of satellites in LEO for generations to come.
More and more satellites being launched means having effective measures to deal with de-orbiting them at the end of their useful life, otherwise even more debris will be a natural consequence of such measures being inadequate and of the consequential likelihood of collisions. Various debris mitigation mission demonstrators have already been tested but need large-scale commercial development. The need for such missions in tackling inceasing volumes of debris should be offset as LEO constellation operators are building-in de-orbiting protocols and technologies to their spacecraft. Hopefully, this means that LEO will be a resource that is well-managed with long-term good husbandry in mind, albeit that with the LEO satellite lifespan being about five years constellation operators will continuously need to replace satellites, requiring frequent launches and deliberate de-orbiting, leading to a constant turnover within LEO, and the risk of more derelicts from failed satellites.
Rules of the Road
There are non-binding guidelines which try to minimize the proliferation of debris:
- The Inter-Agency Space Debris Coordination Committee (IADC) Space Debris Mitigation Guidelines
- The UN Committee on the Peaceful Uses of Outer Space (COPUOS)/UN Office for Outer Space Affairs (OOSA) Long-Term Sustainability guidelines
- NASA guidelines
Broadly, these state that during the active life of satellites, operators should maneuvre them to avoid collision, and at the end of spacecraft life, it is expected that a spacecraft will either be moved to a graveyard orbit (see above), or left in a lower orbit where it will decay due to atmospheric drag within 25 years. The open question regarding the latter provision is, “Is this sufficient?”
The ‘Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies’ (the “Outer Space Treaty”) recognizes that the activities of each satellite operator have potential consequences for other operators. It also provides that “States shall be responsible for national space activities whether carried out by governmental or non-governmental entities.” Indeed, there is a growing momentum behind the view that we should be explicitly considering orbital space as an “environment” just as we recognize the “environment” of the planet’s surface and in the ocean depths. This momentum is evidenced in the G7 Summit statement on space sustainability in 2021; the World Economic Forum, European Space Agency, Massachusetts Institute of Technology, University of Texas, and the analytics consutancy, BryceTech, development of a ‘Space Sustainability Rating’.
Concrete and Coordinated Action
Space activity subject to environmental law is proposed as a necessary key step in translating international good intentions into concrete action, with each sovereign state recognizing its global responsibility just as with other environmental issues such as climate change and plastics in the ocean. Naturally, it is better for the satellite industry if the LEO satellite opertors, in acting upon the recognition that their operations have potential consequences for other operators, maintain the usable orbital environment in good order based on rational commercial self-interest, as has been evident in the historical good husbandry of GEO.
The presence of more, and seemingly ever-larger, LEO constellations will put extreme pressure on conjunction threat asessment good practice, and place under increasingly severe stress collision avoidance maneuvring systems. Orbital space has a finite traffic-carrying capacity, an upper limit which will guarantee our usable orbital resource for the safe conduct of our satellite operations. The question is one of exactly when may we expect to see a universally acknowledged definition of this limit, and even if and when recognized, we have a jointly managed system for the long-term strategic prevention of the “Kessler Syndrome”.
This lengthy article has been prompted by one of GVF’s panel sessions during the forthcoming CABSAT SatExpo Summit. I introduced all three of the GVF sessions in my column here last month, so please join us over 17-18 May for ‘Stakes and Solutions in Responsibly Managing Space’ and for ‘Disruptive Evolution in the Satellite Ground Segment’ and ‘Driving a New Space Innovation Paradigm with Artificial Intelligence and Machine Learning’.
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Martin Jarrold is Vice-President of International Program Development of GVF. He can be reached at: martin.jarold@gvf.org
