SPACE LAW
Australia’s Essential Contribution to ‘Space Domain Awareness’ DUNCAN BLAKE, SPECIAL COUNSEL, SPACE LAW, INTERNATIONAL AEROSPACE LAW & POLICY GROUP
“S
pace Domain Awareness” (SDA) is knowledge of what space objects are in orbit and what they’re doing, as well as what is happening in the space environment itself.1 SDA is essential to the safe, secure, sustainable and responsible use of space by all space operators. In spite of several legal uncertainties that arise from SDA activities, Australia is making an increasing contribution to the collection, global sharing and use of SDA data. As at January, 2020, somewhere between 9000 and 10000 satellites have been placed in orbit since the beginning of the space age in 1957.2 Yet, within the next decade, governments, commercial entities and universities plan to add 20,000 to 50,000 new satellites, some of which are independent satellites, but most of which are parts of ‘mega-constellations’ of satellites acting cooperatively.3 Some of these are Australian.4 This is in addition to the approximately 22,000 pieces of space debris currently in orbit and big enough to be tracked, the approximately 1 million pieces of space debris currently in orbit that are not big enough to be tracked but still big enough to destroy a satellite on impact, or least render it inoperative, and the approximately 128 million even smaller pieces of space debris, that would still at least damage a satellite on impact, if not render it inoperative.5 Collisions between satellites and space debris happen regularly. The International Space Station (ISS), for example, is pitted with impacts from pieces of space debris, and although it has not (yet)
14 THE BULLETIN March 2020
been hit with debris big enough to do significant damage, the crew have been directed to begin evacuation drills with increasing frequency, and the ISS has been manoeuvred, at enormous cost, around 1.5 times each year to avoid space debris.6 On average, a satellite operator somewhere receives a warning of a possible collision close to 2,000 times each day.7 Such warnings can only provide a probability of collision, usually in the order of 1/10000 – the sensors and the data they provide are simply not accurate enough to assert a certainty of collision.8 So, satellite operators only occasionally respond to such warnings. Many satellites lack propulsion, so they can’t move anyway, and other satellite operators do not wish to waste precious fuel to manoeuvre a satellite in response to something that has only a small chance of happening. The fuel would otherwise be used to do “station-keeping”, to make sure that the satellite maintains an orbit and an altitude that enables it to provide the services for which its customers are paying. Thus, when the operators of an Iridium satellite (part of a constellation that provides global satellite communications, particularly for the maritime market) were given a warning of a collision with a defunct Russian military satellite (Kosmos 2251) on 10 February, 2009, with an anticipated miss distance of 584 metres based on probabilistic calculations, they made a commercial decision not to move the satellite. The two satellites “beat” the
odds and actually collided, producing a cloud of around 2000 extra pieces of debris, each of which could subsequently go on to collide with other satellites or pieces of debris.9 (The phenomenon whereby one collision produces debris that goes on to collide with other things, creating more debris, and so on, in a never-ending “cascade”, is known as the “Kessler Syndrome”, and some experts believe we are already at the point where this is inevitable). The addition of 20,000 to 50,000 new satellites exacerbates the problem. The biggest of the prospective megaconstellations is the Starlink constellation. Elon Musk – one of the founders of PayPal, the Tesla motor vehicle company and battery producer (including for South Australia), and the SpaceX rocket company – has already launched 180 of an eventual constellation of up to 12,000 satellites and his company recently sought permission to use frequency for 30,000 additional satellites.10 One of the first batch of Starlink satellites that are already in orbit was recently the subject of a collision warning with a scientific satellite from the European Space Agency (ESA). The warning was given to both organisations in anticipation that they would liaise in order to determine who should move. They had begun liaison, but apparently the Starlink operators were unable to communicate with ESA during the crucial moments, and so ESA made an independent decision to move their satellite, thereby diminishing the future utility of the ESA satellite.11
